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[CostModel][X86] Attempt to match cheap v4f32 shuffles that map to SHUFPS instruction #121778

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Merged
merged 1 commit into from
Jan 6, 2025
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[CostModel][X86] Attempt to match cheap v4f32 shuffles that map to SHUFPS instruction #121778

merged 1 commit into from
Jan 6, 2025

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@RKSimon RKSimon commented Jan 6, 2025

Avoid always assuming the worst for v4f32 2 input shuffles, and match the SHUFPS pattern where possible - each pair of output elements must come from the same source register.

@RKSimon
[CostModel][X86] Attempt to match cheap v4f32 shuffles that map to SH…
5bf964e 
…UFPS instruction

Avoid always assuming the worst for v4f32 2 input shuffles, and match the SHUFPS pattern where possible - each pair of output elements must come from the same source register.
@llvmbot llvmbot added backend:X86 llvm:analysis Includes value tracking, cost tables and constant folding llvm:transforms labels Jan 6, 2025
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llvmbot commented Jan 6, 2025

@llvm/pr-subscribers-llvm-transforms

Author: Simon Pilgrim (RKSimon)

Changes

Avoid always assuming the worst for v4f32 2 input shuffles, and match the SHUFPS pattern where possible - each pair of output elements must come from the same source register.

Patch is 159.92 KiB, truncated to 20.00 KiB below, full version: https://github.com/llvm/llvm-project/pull/121778.diff

14 Files Affected:

  • (modified) llvm/lib/Target/X86/X86TargetTransformInfo.cpp (+10-1)
  • (modified) llvm/test/Analysis/CostModel/X86/alternate-shuffle-cost.ll (+3-15)
  • (modified) llvm/test/Analysis/CostModel/X86/reduction.ll (+8-8)
  • (modified) llvm/test/Analysis/CostModel/X86/shuffle-insert_subvector-codesize.ll (+32-94)
  • (modified) llvm/test/Analysis/CostModel/X86/shuffle-insert_subvector-latency.ll (+32-94)
  • (modified) llvm/test/Analysis/CostModel/X86/shuffle-insert_subvector-sizelatency.ll (+32-94)
  • (modified) llvm/test/Analysis/CostModel/X86/shuffle-insert_subvector.ll (+32-94)
  • (modified) llvm/test/Analysis/CostModel/X86/shuffle-splice-codesize.ll (+1-1)
  • (modified) llvm/test/Analysis/CostModel/X86/shuffle-splice-latency.ll (+1-1)
  • (modified) llvm/test/Analysis/CostModel/X86/shuffle-splice-sizelatency.ll (+1-1)
  • (modified) llvm/test/Analysis/CostModel/X86/shuffle-splice.ll (+1-1)
  • (modified) llvm/test/Transforms/PhaseOrdering/X86/hadd.ll (+13-31)
  • (modified) llvm/test/Transforms/PhaseOrdering/X86/hsub.ll (+13-31)
  • (modified) llvm/test/Transforms/VectorCombine/X86/shuffle-of-cmps.ll (+7-23)
diff --git a/llvm/lib/Target/X86/X86TargetTransformInfo.cpp b/llvm/lib/Target/X86/X86TargetTransformInfo.cpp
index 5d07507457eec5..7a7554cdb99088 100644
--- a/llvm/lib/Target/X86/X86TargetTransformInfo.cpp
+++ b/llvm/lib/Target/X86/X86TargetTransformInfo.cpp
@@ -2226,9 +2226,18 @@ InstructionCost X86TTIImpl::getShuffleCost(
     { TTI::SK_PermuteTwoSrc,    MVT::v4f32, 2 }, // 2*shufps
   };
 
-  if (ST->hasSSE1())
+  if (ST->hasSSE1()) {
+    if (LT.first == 1 && LT.second == MVT::v4f32 && Mask.size() == 4) {
+      // SHUFPS: both pairs must come from the same source register.
+      auto MatchSHUFPS = [](int X, int Y) {
+        return X < 0 || Y < 0 || ((X & 4) == (Y & 4));
+      };
+      if (MatchSHUFPS(Mask[0], Mask[1]) && MatchSHUFPS(Mask[2], Mask[3]))
+        return 1;
+    }
     if (const auto *Entry = CostTableLookup(SSE1ShuffleTbl, Kind, LT.second))
       return LT.first * Entry->Cost;
+  }
 
   return BaseT::getShuffleCost(Kind, BaseTp, Mask, CostKind, Index, SubTp);
 }
diff --git a/llvm/test/Analysis/CostModel/X86/alternate-shuffle-cost.ll b/llvm/test/Analysis/CostModel/X86/alternate-shuffle-cost.ll
index 21a92c45591718..033537d93bf777 100644
--- a/llvm/test/Analysis/CostModel/X86/alternate-shuffle-cost.ll
+++ b/llvm/test/Analysis/CostModel/X86/alternate-shuffle-cost.ll
@@ -247,21 +247,9 @@ define <4 x float> @test_v4f32_2(<4 x float> %a, <4 x float> %b) {
 }
 
 define <4 x float> @test_v4f32_3(<4 x float> %a, <4 x float> %b) {
-; SSE2-LABEL: 'test_v4f32_3'
-; SSE2-NEXT:  Cost Model: Found an estimated cost of 2 for instruction: %1 = shufflevector <4 x float> %a, <4 x float> %b, <4 x i32> <i32 4, i32 5, i32 2, i32 3>
-; SSE2-NEXT:  Cost Model: Found an estimated cost of 0 for instruction: ret <4 x float> %1
-;
-; SSSE3-LABEL: 'test_v4f32_3'
-; SSSE3-NEXT:  Cost Model: Found an estimated cost of 2 for instruction: %1 = shufflevector <4 x float> %a, <4 x float> %b, <4 x i32> <i32 4, i32 5, i32 2, i32 3>
-; SSSE3-NEXT:  Cost Model: Found an estimated cost of 0 for instruction: ret <4 x float> %1
-;
-; SSE42-LABEL: 'test_v4f32_3'
-; SSE42-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %1 = shufflevector <4 x float> %a, <4 x float> %b, <4 x i32> <i32 4, i32 5, i32 2, i32 3>
-; SSE42-NEXT:  Cost Model: Found an estimated cost of 0 for instruction: ret <4 x float> %1
-;
-; AVX-LABEL: 'test_v4f32_3'
-; AVX-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %1 = shufflevector <4 x float> %a, <4 x float> %b, <4 x i32> <i32 4, i32 5, i32 2, i32 3>
-; AVX-NEXT:  Cost Model: Found an estimated cost of 0 for instruction: ret <4 x float> %1
+; CHECK-LABEL: 'test_v4f32_3'
+; CHECK-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %1 = shufflevector <4 x float> %a, <4 x float> %b, <4 x i32> <i32 4, i32 5, i32 2, i32 3>
+; CHECK-NEXT:  Cost Model: Found an estimated cost of 0 for instruction: ret <4 x float> %1
 ;
   %1 = shufflevector <4 x float> %a, <4 x float> %b, <4 x i32> <i32 4, i32 5, i32 2, i32 3>
   ret <4 x float> %1
diff --git a/llvm/test/Analysis/CostModel/X86/reduction.ll b/llvm/test/Analysis/CostModel/X86/reduction.ll
index c55545998d57f6..d7cf8e6cb8905b 100644
--- a/llvm/test/Analysis/CostModel/X86/reduction.ll
+++ b/llvm/test/Analysis/CostModel/X86/reduction.ll
@@ -926,8 +926,8 @@ define fastcc double @pairwise_reduction4double(<4 x double> %rdx, double %f1) {
 
 define fastcc float @pairwise_reduction8float(<8 x float> %rdx, float %f1) {
 ; SSE2-LABEL: 'pairwise_reduction8float'
-; SSE2-NEXT:  Cost Model: Found an estimated cost of 2 for instruction: %rdx.shuf.0.0 = shufflevector <8 x float> %rdx, <8 x float> undef, <8 x i32> <i32 0, i32 2, i32 4, i32 6, i32 poison, i32 poison, i32 poison, i32 poison>
-; SSE2-NEXT:  Cost Model: Found an estimated cost of 2 for instruction: %rdx.shuf.0.1 = shufflevector <8 x float> %rdx, <8 x float> undef, <8 x i32> <i32 1, i32 3, i32 5, i32 7, i32 poison, i32 poison, i32 poison, i32 poison>
+; SSE2-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %rdx.shuf.0.0 = shufflevector <8 x float> %rdx, <8 x float> undef, <8 x i32> <i32 0, i32 2, i32 4, i32 6, i32 poison, i32 poison, i32 poison, i32 poison>
+; SSE2-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %rdx.shuf.0.1 = shufflevector <8 x float> %rdx, <8 x float> undef, <8 x i32> <i32 1, i32 3, i32 5, i32 7, i32 poison, i32 poison, i32 poison, i32 poison>
 ; SSE2-NEXT:  Cost Model: Found an estimated cost of 4 for instruction: %bin.rdx = fadd <8 x float> %rdx.shuf.0.0, %rdx.shuf.0.1
 ; SSE2-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %rdx.shuf.1.0 = shufflevector <8 x float> %bin.rdx, <8 x float> undef, <8 x i32> <i32 0, i32 2, i32 poison, i32 poison, i32 poison, i32 poison, i32 poison, i32 poison>
 ; SSE2-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %rdx.shuf.1.1 = shufflevector <8 x float> %bin.rdx, <8 x float> undef, <8 x i32> <i32 1, i32 3, i32 poison, i32 poison, i32 poison, i32 poison, i32 poison, i32 poison>
@@ -939,8 +939,8 @@ define fastcc float @pairwise_reduction8float(<8 x float> %rdx, float %f1) {
 ; SSE2-NEXT:  Cost Model: Found an estimated cost of 0 for instruction: ret float %r
 ;
 ; SSSE3-LABEL: 'pairwise_reduction8float'
-; SSSE3-NEXT:  Cost Model: Found an estimated cost of 2 for instruction: %rdx.shuf.0.0 = shufflevector <8 x float> %rdx, <8 x float> undef, <8 x i32> <i32 0, i32 2, i32 4, i32 6, i32 poison, i32 poison, i32 poison, i32 poison>
-; SSSE3-NEXT:  Cost Model: Found an estimated cost of 2 for instruction: %rdx.shuf.0.1 = shufflevector <8 x float> %rdx, <8 x float> undef, <8 x i32> <i32 1, i32 3, i32 5, i32 7, i32 poison, i32 poison, i32 poison, i32 poison>
+; SSSE3-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %rdx.shuf.0.0 = shufflevector <8 x float> %rdx, <8 x float> undef, <8 x i32> <i32 0, i32 2, i32 4, i32 6, i32 poison, i32 poison, i32 poison, i32 poison>
+; SSSE3-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %rdx.shuf.0.1 = shufflevector <8 x float> %rdx, <8 x float> undef, <8 x i32> <i32 1, i32 3, i32 5, i32 7, i32 poison, i32 poison, i32 poison, i32 poison>
 ; SSSE3-NEXT:  Cost Model: Found an estimated cost of 4 for instruction: %bin.rdx = fadd <8 x float> %rdx.shuf.0.0, %rdx.shuf.0.1
 ; SSSE3-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %rdx.shuf.1.0 = shufflevector <8 x float> %bin.rdx, <8 x float> undef, <8 x i32> <i32 0, i32 2, i32 poison, i32 poison, i32 poison, i32 poison, i32 poison, i32 poison>
 ; SSSE3-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %rdx.shuf.1.1 = shufflevector <8 x float> %bin.rdx, <8 x float> undef, <8 x i32> <i32 1, i32 3, i32 poison, i32 poison, i32 poison, i32 poison, i32 poison, i32 poison>
@@ -952,8 +952,8 @@ define fastcc float @pairwise_reduction8float(<8 x float> %rdx, float %f1) {
 ; SSSE3-NEXT:  Cost Model: Found an estimated cost of 0 for instruction: ret float %r
 ;
 ; SSE42-LABEL: 'pairwise_reduction8float'
-; SSE42-NEXT:  Cost Model: Found an estimated cost of 2 for instruction: %rdx.shuf.0.0 = shufflevector <8 x float> %rdx, <8 x float> undef, <8 x i32> <i32 0, i32 2, i32 4, i32 6, i32 poison, i32 poison, i32 poison, i32 poison>
-; SSE42-NEXT:  Cost Model: Found an estimated cost of 2 for instruction: %rdx.shuf.0.1 = shufflevector <8 x float> %rdx, <8 x float> undef, <8 x i32> <i32 1, i32 3, i32 5, i32 7, i32 poison, i32 poison, i32 poison, i32 poison>
+; SSE42-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %rdx.shuf.0.0 = shufflevector <8 x float> %rdx, <8 x float> undef, <8 x i32> <i32 0, i32 2, i32 4, i32 6, i32 poison, i32 poison, i32 poison, i32 poison>
+; SSE42-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %rdx.shuf.0.1 = shufflevector <8 x float> %rdx, <8 x float> undef, <8 x i32> <i32 1, i32 3, i32 5, i32 7, i32 poison, i32 poison, i32 poison, i32 poison>
 ; SSE42-NEXT:  Cost Model: Found an estimated cost of 2 for instruction: %bin.rdx = fadd <8 x float> %rdx.shuf.0.0, %rdx.shuf.0.1
 ; SSE42-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %rdx.shuf.1.0 = shufflevector <8 x float> %bin.rdx, <8 x float> undef, <8 x i32> <i32 0, i32 2, i32 poison, i32 poison, i32 poison, i32 poison, i32 poison, i32 poison>
 ; SSE42-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %rdx.shuf.1.1 = shufflevector <8 x float> %bin.rdx, <8 x float> undef, <8 x i32> <i32 1, i32 3, i32 poison, i32 poison, i32 poison, i32 poison, i32 poison, i32 poison>
@@ -991,8 +991,8 @@ define fastcc float @pairwise_reduction8float(<8 x float> %rdx, float %f1) {
 ; AVX2-NEXT:  Cost Model: Found an estimated cost of 0 for instruction: ret float %r
 ;
 ; SLM-LABEL: 'pairwise_reduction8float'
-; SLM-NEXT:  Cost Model: Found an estimated cost of 2 for instruction: %rdx.shuf.0.0 = shufflevector <8 x float> %rdx, <8 x float> undef, <8 x i32> <i32 0, i32 2, i32 4, i32 6, i32 poison, i32 poison, i32 poison, i32 poison>
-; SLM-NEXT:  Cost Model: Found an estimated cost of 2 for instruction: %rdx.shuf.0.1 = shufflevector <8 x float> %rdx, <8 x float> undef, <8 x i32> <i32 1, i32 3, i32 5, i32 7, i32 poison, i32 poison, i32 poison, i32 poison>
+; SLM-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %rdx.shuf.0.0 = shufflevector <8 x float> %rdx, <8 x float> undef, <8 x i32> <i32 0, i32 2, i32 4, i32 6, i32 poison, i32 poison, i32 poison, i32 poison>
+; SLM-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %rdx.shuf.0.1 = shufflevector <8 x float> %rdx, <8 x float> undef, <8 x i32> <i32 1, i32 3, i32 5, i32 7, i32 poison, i32 poison, i32 poison, i32 poison>
 ; SLM-NEXT:  Cost Model: Found an estimated cost of 2 for instruction: %bin.rdx = fadd <8 x float> %rdx.shuf.0.0, %rdx.shuf.0.1
 ; SLM-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %rdx.shuf.1.0 = shufflevector <8 x float> %bin.rdx, <8 x float> undef, <8 x i32> <i32 0, i32 2, i32 poison, i32 poison, i32 poison, i32 poison, i32 poison, i32 poison>
 ; SLM-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %rdx.shuf.1.1 = shufflevector <8 x float> %bin.rdx, <8 x float> undef, <8 x i32> <i32 1, i32 3, i32 poison, i32 poison, i32 poison, i32 poison, i32 poison, i32 poison>
diff --git a/llvm/test/Analysis/CostModel/X86/shuffle-insert_subvector-codesize.ll b/llvm/test/Analysis/CostModel/X86/shuffle-insert_subvector-codesize.ll
index bcba890867ed21..11ee433cae26c2 100644
--- a/llvm/test/Analysis/CostModel/X86/shuffle-insert_subvector-codesize.ll
+++ b/llvm/test/Analysis/CostModel/X86/shuffle-insert_subvector-codesize.ll
@@ -133,98 +133,36 @@ define void @test_vXi64(<2 x i64> %src128, <4 x i64> %src256, <8 x i64> %src512)
 }
 
 define void @test_vXf32(<2 x float> %src64, <4 x float> %src128, <8 x float> %src256, <16 x float> %src512) {
-; SSE2-LABEL: 'test_vXf32'
-; SSE2-NEXT:  Cost Model: Found an estimated cost of 0 for instruction: %src64_128 = shufflevector <2 x float> %src64, <2 x float> undef, <4 x i32> <i32 0, i32 1, i32 poison, i32 poison>
-; SSE2-NEXT:  Cost Model: Found an estimated cost of 0 for instruction: %src64_256 = shufflevector <2 x float> %src64, <2 x float> undef, <8 x i32> <i32 0, i32 1, i32 poison, i32 poison, i32 poison, i32 poison, i32 poison, i32 poison>
-; SSE2-NEXT:  Cost Model: Found an estimated cost of 0 for instruction: %src64_512 = shufflevector <2 x float> %src64, <2 x float> undef, <16 x i32> <i32 0, i32 1, i32 poison, i32 poison, i32 poison, i32 poison, i32 poison, i32 poison, i32 poison, i32 poison, i32 poison, i32 poison, i32 poison, i32 poison, i32 poison, i32 poison>
-; SSE2-NEXT:  Cost Model: Found an estimated cost of 0 for instruction: %src128_256 = shufflevector <4 x float> %src128, <4 x float> undef, <8 x i32> <i32 0, i32 1, i32 2, i32 3, i32 poison, i32 poison, i32 poison, i32 poison>
-; SSE2-NEXT:  Cost Model: Found an estimated cost of 0 for instruction: %src128_512 = shufflevector <4 x float> %src128, <4 x float> undef, <16 x i32> <i32 0, i32 1, i32 2, i32 3, i32 poison, i32 poison, i32 poison, i32 poison, i32 poison, i32 poison, i32 poison, i32 poison, i32 poison, i32 poison, i32 poison, i32 poison>
-; SSE2-NEXT:  Cost Model: Found an estimated cost of 0 for instruction: %src256_512 = shufflevector <8 x float> %src256, <8 x float> undef, <16 x i32> <i32 0, i32 1, i32 2, i32 3, i32 4, i32 5, i32 6, i32 7, i32 poison, i32 poison, i32 poison, i32 poison, i32 poison, i32 poison, i32 poison, i32 poison>
-; SSE2-NEXT:  Cost Model: Found an estimated cost of 2 for instruction: %V128_01 = shufflevector <4 x float> %src128, <4 x float> %src64_128, <4 x i32> <i32 4, i32 5, i32 2, i32 3>
-; SSE2-NEXT:  Cost Model: Found an estimated cost of 2 for instruction: %V128_23 = shufflevector <4 x float> %src128, <4 x float> %src64_128, <4 x i32> <i32 0, i32 1, i32 4, i32 5>
-; SSE2-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %V256_01 = shufflevector <8 x float> %src256, <8 x float> %src64_256, <8 x i32> <i32 8, i32 9, i32 2, i32 3, i32 4, i32 5, i32 6, i32 7>
-; SSE2-NEXT:  Cost Model: Found an estimated cost of 2 for instruction: %V256_23 = shufflevector <8 x float> %src256, <8 x float> %src64_256, <8 x i32> <i32 0, i32 1, i32 8, i32 9, i32 4, i32 5, i32 6, i32 7>
-; SSE2-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %V256_45 = shufflevector <8 x float> %src256, <8 x float> %src64_256, <8 x i32> <i32 0, i32 1, i32 2, i32 3, i32 8, i32 9, i32 6, i32 7>
-; SSE2-NEXT:  Cost Model: Found an estimated cost of 2 for instruction: %V256_67 = shufflevector <8 x float> %src256, <8 x float> %src64_256, <8 x i32> <i32 0, i32 1, i32 2, i32 3, i32 4, i32 5, i32 8, i32 9>
-; SSE2-NEXT:  Cost Model: Found an estimated cost of 0 for instruction: %V256_0123 = shufflevector <8 x float> %src256, <8 x float> %src128_256, <8 x i32> <i32 8, i32 9, i32 10, i32 11, i32 4, i32 5, i32 6, i32 7>
-; SSE2-NEXT:  Cost Model: Found an estimated cost of 0 for instruction: %V256_4567 = shufflevector <8 x float> %src256, <8 x float> %src128_256, <8 x i32> <i32 0, i32 1, i32 2, i32 3, i32 8, i32 9, i32 10, i32 11>
-; SSE2-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %V512_01 = shufflevector <16 x float> %src512, <16 x float> %src64_512, <16 x i32> <i32 16, i32 17, i32 2, i32 3, i32 4, i32 5, i32 6, i32 7, i32 8, i32 9, i32 10, i32 11, i32 12, i32 13, i32 14, i32 15>
-; SSE2-NEXT:  Cost Model: Found an estimated cost of 2 for instruction: %V512_23 = shufflevector <16 x float> %src512, <16 x float> %src64_512, <16 x i32> <i32 0, i32 1, i32 16, i32 17, i32 4, i32 5, i32 6, i32 7, i32 8, i32 9, i32 10, i32 11, i32 12, i32 13, i32 14, i32 15>
-; SSE2-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %V512_45 = shufflevector <16 x float> %src512, <16 x float> %src64_512, <16 x i32> <i32 0, i32 1, i32 2, i32 3, i32 16, i32 17, i32 6, i32 7, i32 8, i32 9, i32 10, i32 11, i32 12, i32 13, i32 14, i32 15>
-; SSE2-NEXT:  Cost Model: Found an estimated cost of 2 for instruction: %V512_67 = shufflevector <16 x float> %src512, <16 x float> %src64_512, <16 x i32> <i32 0, i32 1, i32 2, i32 3, i32 4, i32 5, i32 16, i32 17, i32 8, i32 9, i32 10, i32 11, i32 12, i32 13, i32 14, i32 15>
-; SSE2-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %V512_89 = shufflevector <16 x float> %src512, <16 x float> %src64_512, <16 x i32> <i32 0, i32 1, i32 2, i32 3, i32 4, i32 5, i32 6, i32 7, i32 16, i32 17, i32 10, i32 11, i32 12, i32 13, i32 14, i32 15>
-; SSE2-NEXT:  Cost Model: Found an estimated cost of 2 for instruction: %V512_AB = shufflevector <16 x float> %src512, <16 x float> %src64_512, <16 x i32> <i32 0, i32 1, i32 2, i32 3, i32 4, i32 5, i32 6, i32 7, i32 8, i32 9, i32 16, i32 17, i32 12, i32 13, i32 14, i32 15>
-; SSE2-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %V512_CD = shufflevector <16 x float> %src512, <16 x float> %src64_512, <16 x i32> <i32 0, i32 1, i32 2, i32 3, i32 4, i32 5, i32 6, i32 7, i32 8, i32 9, i32 10, i32 11, i32 16, i32 17, i32 14, i32 15>
-; SSE2-NEXT:  Cost Model: Found an estimated cost of 2 for instruction: %V512_EF = shufflevector <16 x float> %src512, <16 x float> %src64_512, <16 x i32> <i32 0, i32 1, i32 2, i32 3, i32 4, i32 5, i32 6, i32 7, i32 8, i32 9, i32 10, i32 11, i32 12, i32 13, i32 16, i32 17>
-; SSE2-NEXT:  Cost Model: Found an estimated cost of 0 for instruction: %V512_0123 = shufflevector <16 x float> %src512, <16 x float> %src128_512, <16 x i32> <i32 16, i32 17, i32 18, i32 19, i32 4, i32 5, i32 6, i32 7, i32 8, i32 9, i32 10, i32 11, i32 12, i32 13, i32 14, i32 15>
-; SSE2-NEXT:  Cost Model: Found an estimated cost of 0 for instruction: %V512_4567 = shufflevector <16 x float> %src512, <16 x float> %src128_512, <16 x i32> <i32 0, i32 1, i32 2, i32 3, i32 16, i32 17, i32 18, i32 19, i32 8, i32 9, i32 10, i32 11, i32 12, i32 13, i32 14, i32 15>
-; SSE2-NEXT:  Cost Model: Found an estimated cost of 0 for instruction: %V512_89AB = shufflevector <16 x float> %src512, <16 x float> %src128_512, <16 x i32> <i32 0, i32 1, i32 2, i32 3, i32 4, i32 5, i32 6, i32 7, i32 16, i32 17, i32 18, i32 19, i32 12, i32 13, i32 14, i32 15>
-; SSE2-NEXT:  Cost Model: Found an estimated cost of 0 for instruction: %V512_CDEF = shufflevector <16 x float> %src512, <16 x float> %src128_512, <16 x i32> <i32 0, i32 1, i32 2, i32 3, i32 4, i32 5, i32 6, i32 7, i32 8, i32 9, i32 10, i32 11, i32 16, i32 17, i32 18, i32 19>
-; SSE2-NEXT:  Cost Model: Found an estimated cost of 0 for instruction: %V512_01234567 = shufflevector <16 x float> %src512, <16 x float> %src128_512, <16 x i32> <i32 16, i32 17, i32 18, i32 19, i32 20, i32 21, i32 22, i32 23, i32 8, i32 9, i32 10, i32 11, i32 12, i32 13, i32 14, i32 15>
-; SSE2-NEXT:  Cost Model: Found an estimated cost of 0 for instruction: %V512_89ABCDEF = shufflevector <16 x float> %src512, <16 x float> %src128_512, <16 x i32> <i32 0, i32 1, i32 2, i32 3, i32 4, i32 5, i32 6, i32 7, i32 16, i32 17, i32 18, i32 19, i32 20, i32 21, i32 22, i32 23>
-; SSE2-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: ret void
-;
-; SSSE3-LABEL: 'test_vXf32'
-; SSSE3-NEXT:  Cost Model: Found an estimated cost of 0 for instruction: %src64_128 = shufflevector <2 x float> %src64, <2 x float> undef, <4 x i32> <i32 0, i32 1, i32 poison, i32 poison>
-; SSSE3-NEXT:  Cost Model: Found an estimated cost of 0 for instruction: %src64_256 = shufflevector <2 x float> %src64, <2 x float> undef, <8 x i32> <i32 0, i32 1, i32 poison, i32 poison, i32 poison, i32 poison, i32 poison, i32 poison>
-; SSSE3-NEXT:  Cost Model: Found an estimated cost of 0 for instruction: %src64_512 = shufflevector <2 x float> %src64, <2 x float> undef, <16 x i32> <i32 0, i32 1, i32 poison, i32 poison, i32 poison, i32 poison, i32 poison, i32 poison, i32 poison, i32 poison, i32 poison, i32 poison, i32 poison, i32 poison, i32 poison, i32 poison>
-; SSSE3-NEXT:  Cost Model: Found an estimated cost of 0 for instruction: %src128_256 = shufflevector <4 x float> %src128, <4 x float> undef, <8 x i32> <i32 0, i32 1, i32 2, i32 3, i32 poison, i32 poison, i32 poison, i32 poison>
-; SSSE3-NEXT:  Cost Model: Found an estimated cost of 0 for instruction: %src128_512 = shufflevector <4 x float> %src128, <4 x float> undef, <16 x i32> <i32 0, i32 1, i32 2, i32 3, i32 poison, i32 poison, i32 poison, i32 poison, i32 poison, i32 poison, i32 poison, i32 poison, i32 poison, i32 poison, i32 poison, i32 poison>
-; SSSE3-NEXT:  Cost Model: Found an estimated cost of 0 for instruction: %src256_512 = shufflevector <8 x float> %src256, <8 x float> undef, <16 x i32> <i32 0, i32 1, i32 2, i32 3, i32 4, i32 5, i32 6, i32 7, i32 poison, i32 poison, i32 poison, i32 poison, i32 poison, i32 poison, i32 poison, i32 poison>
-; SSSE3-NEXT:  Cost Model: Found an estimated cost of 2 for instruction: %V128_01 = shufflevector <4 x float> %src128, <4 x float> %src64_128, <4 x i32> <i32 4, i32 5, i32 2, i32 3>
-; SSSE3-NEXT:  Cost Model: Found an estimated cost of 2 for instruction: %V128_23 = shufflevector <4 x float> %src128, <4 x float> %src64_128, <4 x i32> <i32 0, i32 1, i32 4, i32 5>
-; SSSE3-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %V256_01 = shufflevector <8 x float> %src256, <8 x float> %src64_256, <8 x i32> <i32 8, i32 9, i32 2, i32 3, i32 4, i32 5, i32 6, i32 7>
-; SSSE3-NEXT:  Cost Model: Found an estimated cost of 2 for instruction: %V256_23 = shufflevector <8 x float> %src256, <8 x float> %src6...
[truncated]

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llvmbot commented Jan 6, 2025

@llvm/pr-subscribers-llvm-analysis

Author: Simon Pilgrim (RKSimon)

Changes

Avoid always assuming the worst for v4f32 2 input shuffles, and match the SHUFPS pattern where possible - each pair of output elements must come from the same source register.

Patch is 159.92 KiB, truncated to 20.00 KiB below, full version: https://github.com/llvm/llvm-project/pull/121778.diff

14 Files Affected:

  • (modified) llvm/lib/Target/X86/X86TargetTransformInfo.cpp (+10-1)
  • (modified) llvm/test/Analysis/CostModel/X86/alternate-shuffle-cost.ll (+3-15)
  • (modified) llvm/test/Analysis/CostModel/X86/reduction.ll (+8-8)
  • (modified) llvm/test/Analysis/CostModel/X86/shuffle-insert_subvector-codesize.ll (+32-94)
  • (modified) llvm/test/Analysis/CostModel/X86/shuffle-insert_subvector-latency.ll (+32-94)
  • (modified) llvm/test/Analysis/CostModel/X86/shuffle-insert_subvector-sizelatency.ll (+32-94)
  • (modified) llvm/test/Analysis/CostModel/X86/shuffle-insert_subvector.ll (+32-94)
  • (modified) llvm/test/Analysis/CostModel/X86/shuffle-splice-codesize.ll (+1-1)
  • (modified) llvm/test/Analysis/CostModel/X86/shuffle-splice-latency.ll (+1-1)
  • (modified) llvm/test/Analysis/CostModel/X86/shuffle-splice-sizelatency.ll (+1-1)
  • (modified) llvm/test/Analysis/CostModel/X86/shuffle-splice.ll (+1-1)
  • (modified) llvm/test/Transforms/PhaseOrdering/X86/hadd.ll (+13-31)
  • (modified) llvm/test/Transforms/PhaseOrdering/X86/hsub.ll (+13-31)
  • (modified) llvm/test/Transforms/VectorCombine/X86/shuffle-of-cmps.ll (+7-23)
diff --git a/llvm/lib/Target/X86/X86TargetTransformInfo.cpp b/llvm/lib/Target/X86/X86TargetTransformInfo.cpp
index 5d07507457eec5..7a7554cdb99088 100644
--- a/llvm/lib/Target/X86/X86TargetTransformInfo.cpp
+++ b/llvm/lib/Target/X86/X86TargetTransformInfo.cpp
@@ -2226,9 +2226,18 @@ InstructionCost X86TTIImpl::getShuffleCost(
     { TTI::SK_PermuteTwoSrc,    MVT::v4f32, 2 }, // 2*shufps
   };
 
-  if (ST->hasSSE1())
+  if (ST->hasSSE1()) {
+    if (LT.first == 1 && LT.second == MVT::v4f32 && Mask.size() == 4) {
+      // SHUFPS: both pairs must come from the same source register.
+      auto MatchSHUFPS = [](int X, int Y) {
+        return X < 0 || Y < 0 || ((X & 4) == (Y & 4));
+      };
+      if (MatchSHUFPS(Mask[0], Mask[1]) && MatchSHUFPS(Mask[2], Mask[3]))
+        return 1;
+    }
     if (const auto *Entry = CostTableLookup(SSE1ShuffleTbl, Kind, LT.second))
       return LT.first * Entry->Cost;
+  }
 
   return BaseT::getShuffleCost(Kind, BaseTp, Mask, CostKind, Index, SubTp);
 }
diff --git a/llvm/test/Analysis/CostModel/X86/alternate-shuffle-cost.ll b/llvm/test/Analysis/CostModel/X86/alternate-shuffle-cost.ll
index 21a92c45591718..033537d93bf777 100644
--- a/llvm/test/Analysis/CostModel/X86/alternate-shuffle-cost.ll
+++ b/llvm/test/Analysis/CostModel/X86/alternate-shuffle-cost.ll
@@ -247,21 +247,9 @@ define <4 x float> @test_v4f32_2(<4 x float> %a, <4 x float> %b) {
 }
 
 define <4 x float> @test_v4f32_3(<4 x float> %a, <4 x float> %b) {
-; SSE2-LABEL: 'test_v4f32_3'
-; SSE2-NEXT:  Cost Model: Found an estimated cost of 2 for instruction: %1 = shufflevector <4 x float> %a, <4 x float> %b, <4 x i32> <i32 4, i32 5, i32 2, i32 3>
-; SSE2-NEXT:  Cost Model: Found an estimated cost of 0 for instruction: ret <4 x float> %1
-;
-; SSSE3-LABEL: 'test_v4f32_3'
-; SSSE3-NEXT:  Cost Model: Found an estimated cost of 2 for instruction: %1 = shufflevector <4 x float> %a, <4 x float> %b, <4 x i32> <i32 4, i32 5, i32 2, i32 3>
-; SSSE3-NEXT:  Cost Model: Found an estimated cost of 0 for instruction: ret <4 x float> %1
-;
-; SSE42-LABEL: 'test_v4f32_3'
-; SSE42-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %1 = shufflevector <4 x float> %a, <4 x float> %b, <4 x i32> <i32 4, i32 5, i32 2, i32 3>
-; SSE42-NEXT:  Cost Model: Found an estimated cost of 0 for instruction: ret <4 x float> %1
-;
-; AVX-LABEL: 'test_v4f32_3'
-; AVX-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %1 = shufflevector <4 x float> %a, <4 x float> %b, <4 x i32> <i32 4, i32 5, i32 2, i32 3>
-; AVX-NEXT:  Cost Model: Found an estimated cost of 0 for instruction: ret <4 x float> %1
+; CHECK-LABEL: 'test_v4f32_3'
+; CHECK-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %1 = shufflevector <4 x float> %a, <4 x float> %b, <4 x i32> <i32 4, i32 5, i32 2, i32 3>
+; CHECK-NEXT:  Cost Model: Found an estimated cost of 0 for instruction: ret <4 x float> %1
 ;
   %1 = shufflevector <4 x float> %a, <4 x float> %b, <4 x i32> <i32 4, i32 5, i32 2, i32 3>
   ret <4 x float> %1
diff --git a/llvm/test/Analysis/CostModel/X86/reduction.ll b/llvm/test/Analysis/CostModel/X86/reduction.ll
index c55545998d57f6..d7cf8e6cb8905b 100644
--- a/llvm/test/Analysis/CostModel/X86/reduction.ll
+++ b/llvm/test/Analysis/CostModel/X86/reduction.ll
@@ -926,8 +926,8 @@ define fastcc double @pairwise_reduction4double(<4 x double> %rdx, double %f1) {
 
 define fastcc float @pairwise_reduction8float(<8 x float> %rdx, float %f1) {
 ; SSE2-LABEL: 'pairwise_reduction8float'
-; SSE2-NEXT:  Cost Model: Found an estimated cost of 2 for instruction: %rdx.shuf.0.0 = shufflevector <8 x float> %rdx, <8 x float> undef, <8 x i32> <i32 0, i32 2, i32 4, i32 6, i32 poison, i32 poison, i32 poison, i32 poison>
-; SSE2-NEXT:  Cost Model: Found an estimated cost of 2 for instruction: %rdx.shuf.0.1 = shufflevector <8 x float> %rdx, <8 x float> undef, <8 x i32> <i32 1, i32 3, i32 5, i32 7, i32 poison, i32 poison, i32 poison, i32 poison>
+; SSE2-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %rdx.shuf.0.0 = shufflevector <8 x float> %rdx, <8 x float> undef, <8 x i32> <i32 0, i32 2, i32 4, i32 6, i32 poison, i32 poison, i32 poison, i32 poison>
+; SSE2-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %rdx.shuf.0.1 = shufflevector <8 x float> %rdx, <8 x float> undef, <8 x i32> <i32 1, i32 3, i32 5, i32 7, i32 poison, i32 poison, i32 poison, i32 poison>
 ; SSE2-NEXT:  Cost Model: Found an estimated cost of 4 for instruction: %bin.rdx = fadd <8 x float> %rdx.shuf.0.0, %rdx.shuf.0.1
 ; SSE2-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %rdx.shuf.1.0 = shufflevector <8 x float> %bin.rdx, <8 x float> undef, <8 x i32> <i32 0, i32 2, i32 poison, i32 poison, i32 poison, i32 poison, i32 poison, i32 poison>
 ; SSE2-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %rdx.shuf.1.1 = shufflevector <8 x float> %bin.rdx, <8 x float> undef, <8 x i32> <i32 1, i32 3, i32 poison, i32 poison, i32 poison, i32 poison, i32 poison, i32 poison>
@@ -939,8 +939,8 @@ define fastcc float @pairwise_reduction8float(<8 x float> %rdx, float %f1) {
 ; SSE2-NEXT:  Cost Model: Found an estimated cost of 0 for instruction: ret float %r
 ;
 ; SSSE3-LABEL: 'pairwise_reduction8float'
-; SSSE3-NEXT:  Cost Model: Found an estimated cost of 2 for instruction: %rdx.shuf.0.0 = shufflevector <8 x float> %rdx, <8 x float> undef, <8 x i32> <i32 0, i32 2, i32 4, i32 6, i32 poison, i32 poison, i32 poison, i32 poison>
-; SSSE3-NEXT:  Cost Model: Found an estimated cost of 2 for instruction: %rdx.shuf.0.1 = shufflevector <8 x float> %rdx, <8 x float> undef, <8 x i32> <i32 1, i32 3, i32 5, i32 7, i32 poison, i32 poison, i32 poison, i32 poison>
+; SSSE3-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %rdx.shuf.0.0 = shufflevector <8 x float> %rdx, <8 x float> undef, <8 x i32> <i32 0, i32 2, i32 4, i32 6, i32 poison, i32 poison, i32 poison, i32 poison>
+; SSSE3-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %rdx.shuf.0.1 = shufflevector <8 x float> %rdx, <8 x float> undef, <8 x i32> <i32 1, i32 3, i32 5, i32 7, i32 poison, i32 poison, i32 poison, i32 poison>
 ; SSSE3-NEXT:  Cost Model: Found an estimated cost of 4 for instruction: %bin.rdx = fadd <8 x float> %rdx.shuf.0.0, %rdx.shuf.0.1
 ; SSSE3-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %rdx.shuf.1.0 = shufflevector <8 x float> %bin.rdx, <8 x float> undef, <8 x i32> <i32 0, i32 2, i32 poison, i32 poison, i32 poison, i32 poison, i32 poison, i32 poison>
 ; SSSE3-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %rdx.shuf.1.1 = shufflevector <8 x float> %bin.rdx, <8 x float> undef, <8 x i32> <i32 1, i32 3, i32 poison, i32 poison, i32 poison, i32 poison, i32 poison, i32 poison>
@@ -952,8 +952,8 @@ define fastcc float @pairwise_reduction8float(<8 x float> %rdx, float %f1) {
 ; SSSE3-NEXT:  Cost Model: Found an estimated cost of 0 for instruction: ret float %r
 ;
 ; SSE42-LABEL: 'pairwise_reduction8float'
-; SSE42-NEXT:  Cost Model: Found an estimated cost of 2 for instruction: %rdx.shuf.0.0 = shufflevector <8 x float> %rdx, <8 x float> undef, <8 x i32> <i32 0, i32 2, i32 4, i32 6, i32 poison, i32 poison, i32 poison, i32 poison>
-; SSE42-NEXT:  Cost Model: Found an estimated cost of 2 for instruction: %rdx.shuf.0.1 = shufflevector <8 x float> %rdx, <8 x float> undef, <8 x i32> <i32 1, i32 3, i32 5, i32 7, i32 poison, i32 poison, i32 poison, i32 poison>
+; SSE42-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %rdx.shuf.0.0 = shufflevector <8 x float> %rdx, <8 x float> undef, <8 x i32> <i32 0, i32 2, i32 4, i32 6, i32 poison, i32 poison, i32 poison, i32 poison>
+; SSE42-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %rdx.shuf.0.1 = shufflevector <8 x float> %rdx, <8 x float> undef, <8 x i32> <i32 1, i32 3, i32 5, i32 7, i32 poison, i32 poison, i32 poison, i32 poison>
 ; SSE42-NEXT:  Cost Model: Found an estimated cost of 2 for instruction: %bin.rdx = fadd <8 x float> %rdx.shuf.0.0, %rdx.shuf.0.1
 ; SSE42-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %rdx.shuf.1.0 = shufflevector <8 x float> %bin.rdx, <8 x float> undef, <8 x i32> <i32 0, i32 2, i32 poison, i32 poison, i32 poison, i32 poison, i32 poison, i32 poison>
 ; SSE42-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %rdx.shuf.1.1 = shufflevector <8 x float> %bin.rdx, <8 x float> undef, <8 x i32> <i32 1, i32 3, i32 poison, i32 poison, i32 poison, i32 poison, i32 poison, i32 poison>
@@ -991,8 +991,8 @@ define fastcc float @pairwise_reduction8float(<8 x float> %rdx, float %f1) {
 ; AVX2-NEXT:  Cost Model: Found an estimated cost of 0 for instruction: ret float %r
 ;
 ; SLM-LABEL: 'pairwise_reduction8float'
-; SLM-NEXT:  Cost Model: Found an estimated cost of 2 for instruction: %rdx.shuf.0.0 = shufflevector <8 x float> %rdx, <8 x float> undef, <8 x i32> <i32 0, i32 2, i32 4, i32 6, i32 poison, i32 poison, i32 poison, i32 poison>
-; SLM-NEXT:  Cost Model: Found an estimated cost of 2 for instruction: %rdx.shuf.0.1 = shufflevector <8 x float> %rdx, <8 x float> undef, <8 x i32> <i32 1, i32 3, i32 5, i32 7, i32 poison, i32 poison, i32 poison, i32 poison>
+; SLM-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %rdx.shuf.0.0 = shufflevector <8 x float> %rdx, <8 x float> undef, <8 x i32> <i32 0, i32 2, i32 4, i32 6, i32 poison, i32 poison, i32 poison, i32 poison>
+; SLM-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %rdx.shuf.0.1 = shufflevector <8 x float> %rdx, <8 x float> undef, <8 x i32> <i32 1, i32 3, i32 5, i32 7, i32 poison, i32 poison, i32 poison, i32 poison>
 ; SLM-NEXT:  Cost Model: Found an estimated cost of 2 for instruction: %bin.rdx = fadd <8 x float> %rdx.shuf.0.0, %rdx.shuf.0.1
 ; SLM-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %rdx.shuf.1.0 = shufflevector <8 x float> %bin.rdx, <8 x float> undef, <8 x i32> <i32 0, i32 2, i32 poison, i32 poison, i32 poison, i32 poison, i32 poison, i32 poison>
 ; SLM-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %rdx.shuf.1.1 = shufflevector <8 x float> %bin.rdx, <8 x float> undef, <8 x i32> <i32 1, i32 3, i32 poison, i32 poison, i32 poison, i32 poison, i32 poison, i32 poison>
diff --git a/llvm/test/Analysis/CostModel/X86/shuffle-insert_subvector-codesize.ll b/llvm/test/Analysis/CostModel/X86/shuffle-insert_subvector-codesize.ll
index bcba890867ed21..11ee433cae26c2 100644
--- a/llvm/test/Analysis/CostModel/X86/shuffle-insert_subvector-codesize.ll
+++ b/llvm/test/Analysis/CostModel/X86/shuffle-insert_subvector-codesize.ll
@@ -133,98 +133,36 @@ define void @test_vXi64(<2 x i64> %src128, <4 x i64> %src256, <8 x i64> %src512)
 }
 
 define void @test_vXf32(<2 x float> %src64, <4 x float> %src128, <8 x float> %src256, <16 x float> %src512) {
-; SSE2-LABEL: 'test_vXf32'
-; SSE2-NEXT:  Cost Model: Found an estimated cost of 0 for instruction: %src64_128 = shufflevector <2 x float> %src64, <2 x float> undef, <4 x i32> <i32 0, i32 1, i32 poison, i32 poison>
-; SSE2-NEXT:  Cost Model: Found an estimated cost of 0 for instruction: %src64_256 = shufflevector <2 x float> %src64, <2 x float> undef, <8 x i32> <i32 0, i32 1, i32 poison, i32 poison, i32 poison, i32 poison, i32 poison, i32 poison>
-; SSE2-NEXT:  Cost Model: Found an estimated cost of 0 for instruction: %src64_512 = shufflevector <2 x float> %src64, <2 x float> undef, <16 x i32> <i32 0, i32 1, i32 poison, i32 poison, i32 poison, i32 poison, i32 poison, i32 poison, i32 poison, i32 poison, i32 poison, i32 poison, i32 poison, i32 poison, i32 poison, i32 poison>
-; SSE2-NEXT:  Cost Model: Found an estimated cost of 0 for instruction: %src128_256 = shufflevector <4 x float> %src128, <4 x float> undef, <8 x i32> <i32 0, i32 1, i32 2, i32 3, i32 poison, i32 poison, i32 poison, i32 poison>
-; SSE2-NEXT:  Cost Model: Found an estimated cost of 0 for instruction: %src128_512 = shufflevector <4 x float> %src128, <4 x float> undef, <16 x i32> <i32 0, i32 1, i32 2, i32 3, i32 poison, i32 poison, i32 poison, i32 poison, i32 poison, i32 poison, i32 poison, i32 poison, i32 poison, i32 poison, i32 poison, i32 poison>
-; SSE2-NEXT:  Cost Model: Found an estimated cost of 0 for instruction: %src256_512 = shufflevector <8 x float> %src256, <8 x float> undef, <16 x i32> <i32 0, i32 1, i32 2, i32 3, i32 4, i32 5, i32 6, i32 7, i32 poison, i32 poison, i32 poison, i32 poison, i32 poison, i32 poison, i32 poison, i32 poison>
-; SSE2-NEXT:  Cost Model: Found an estimated cost of 2 for instruction: %V128_01 = shufflevector <4 x float> %src128, <4 x float> %src64_128, <4 x i32> <i32 4, i32 5, i32 2, i32 3>
-; SSE2-NEXT:  Cost Model: Found an estimated cost of 2 for instruction: %V128_23 = shufflevector <4 x float> %src128, <4 x float> %src64_128, <4 x i32> <i32 0, i32 1, i32 4, i32 5>
-; SSE2-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %V256_01 = shufflevector <8 x float> %src256, <8 x float> %src64_256, <8 x i32> <i32 8, i32 9, i32 2, i32 3, i32 4, i32 5, i32 6, i32 7>
-; SSE2-NEXT:  Cost Model: Found an estimated cost of 2 for instruction: %V256_23 = shufflevector <8 x float> %src256, <8 x float> %src64_256, <8 x i32> <i32 0, i32 1, i32 8, i32 9, i32 4, i32 5, i32 6, i32 7>
-; SSE2-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %V256_45 = shufflevector <8 x float> %src256, <8 x float> %src64_256, <8 x i32> <i32 0, i32 1, i32 2, i32 3, i32 8, i32 9, i32 6, i32 7>
-; SSE2-NEXT:  Cost Model: Found an estimated cost of 2 for instruction: %V256_67 = shufflevector <8 x float> %src256, <8 x float> %src64_256, <8 x i32> <i32 0, i32 1, i32 2, i32 3, i32 4, i32 5, i32 8, i32 9>
-; SSE2-NEXT:  Cost Model: Found an estimated cost of 0 for instruction: %V256_0123 = shufflevector <8 x float> %src256, <8 x float> %src128_256, <8 x i32> <i32 8, i32 9, i32 10, i32 11, i32 4, i32 5, i32 6, i32 7>
-; SSE2-NEXT:  Cost Model: Found an estimated cost of 0 for instruction: %V256_4567 = shufflevector <8 x float> %src256, <8 x float> %src128_256, <8 x i32> <i32 0, i32 1, i32 2, i32 3, i32 8, i32 9, i32 10, i32 11>
-; SSE2-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %V512_01 = shufflevector <16 x float> %src512, <16 x float> %src64_512, <16 x i32> <i32 16, i32 17, i32 2, i32 3, i32 4, i32 5, i32 6, i32 7, i32 8, i32 9, i32 10, i32 11, i32 12, i32 13, i32 14, i32 15>
-; SSE2-NEXT:  Cost Model: Found an estimated cost of 2 for instruction: %V512_23 = shufflevector <16 x float> %src512, <16 x float> %src64_512, <16 x i32> <i32 0, i32 1, i32 16, i32 17, i32 4, i32 5, i32 6, i32 7, i32 8, i32 9, i32 10, i32 11, i32 12, i32 13, i32 14, i32 15>
-; SSE2-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %V512_45 = shufflevector <16 x float> %src512, <16 x float> %src64_512, <16 x i32> <i32 0, i32 1, i32 2, i32 3, i32 16, i32 17, i32 6, i32 7, i32 8, i32 9, i32 10, i32 11, i32 12, i32 13, i32 14, i32 15>
-; SSE2-NEXT:  Cost Model: Found an estimated cost of 2 for instruction: %V512_67 = shufflevector <16 x float> %src512, <16 x float> %src64_512, <16 x i32> <i32 0, i32 1, i32 2, i32 3, i32 4, i32 5, i32 16, i32 17, i32 8, i32 9, i32 10, i32 11, i32 12, i32 13, i32 14, i32 15>
-; SSE2-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %V512_89 = shufflevector <16 x float> %src512, <16 x float> %src64_512, <16 x i32> <i32 0, i32 1, i32 2, i32 3, i32 4, i32 5, i32 6, i32 7, i32 16, i32 17, i32 10, i32 11, i32 12, i32 13, i32 14, i32 15>
-; SSE2-NEXT:  Cost Model: Found an estimated cost of 2 for instruction: %V512_AB = shufflevector <16 x float> %src512, <16 x float> %src64_512, <16 x i32> <i32 0, i32 1, i32 2, i32 3, i32 4, i32 5, i32 6, i32 7, i32 8, i32 9, i32 16, i32 17, i32 12, i32 13, i32 14, i32 15>
-; SSE2-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %V512_CD = shufflevector <16 x float> %src512, <16 x float> %src64_512, <16 x i32> <i32 0, i32 1, i32 2, i32 3, i32 4, i32 5, i32 6, i32 7, i32 8, i32 9, i32 10, i32 11, i32 16, i32 17, i32 14, i32 15>
-; SSE2-NEXT:  Cost Model: Found an estimated cost of 2 for instruction: %V512_EF = shufflevector <16 x float> %src512, <16 x float> %src64_512, <16 x i32> <i32 0, i32 1, i32 2, i32 3, i32 4, i32 5, i32 6, i32 7, i32 8, i32 9, i32 10, i32 11, i32 12, i32 13, i32 16, i32 17>
-; SSE2-NEXT:  Cost Model: Found an estimated cost of 0 for instruction: %V512_0123 = shufflevector <16 x float> %src512, <16 x float> %src128_512, <16 x i32> <i32 16, i32 17, i32 18, i32 19, i32 4, i32 5, i32 6, i32 7, i32 8, i32 9, i32 10, i32 11, i32 12, i32 13, i32 14, i32 15>
-; SSE2-NEXT:  Cost Model: Found an estimated cost of 0 for instruction: %V512_4567 = shufflevector <16 x float> %src512, <16 x float> %src128_512, <16 x i32> <i32 0, i32 1, i32 2, i32 3, i32 16, i32 17, i32 18, i32 19, i32 8, i32 9, i32 10, i32 11, i32 12, i32 13, i32 14, i32 15>
-; SSE2-NEXT:  Cost Model: Found an estimated cost of 0 for instruction: %V512_89AB = shufflevector <16 x float> %src512, <16 x float> %src128_512, <16 x i32> <i32 0, i32 1, i32 2, i32 3, i32 4, i32 5, i32 6, i32 7, i32 16, i32 17, i32 18, i32 19, i32 12, i32 13, i32 14, i32 15>
-; SSE2-NEXT:  Cost Model: Found an estimated cost of 0 for instruction: %V512_CDEF = shufflevector <16 x float> %src512, <16 x float> %src128_512, <16 x i32> <i32 0, i32 1, i32 2, i32 3, i32 4, i32 5, i32 6, i32 7, i32 8, i32 9, i32 10, i32 11, i32 16, i32 17, i32 18, i32 19>
-; SSE2-NEXT:  Cost Model: Found an estimated cost of 0 for instruction: %V512_01234567 = shufflevector <16 x float> %src512, <16 x float> %src128_512, <16 x i32> <i32 16, i32 17, i32 18, i32 19, i32 20, i32 21, i32 22, i32 23, i32 8, i32 9, i32 10, i32 11, i32 12, i32 13, i32 14, i32 15>
-; SSE2-NEXT:  Cost Model: Found an estimated cost of 0 for instruction: %V512_89ABCDEF = shufflevector <16 x float> %src512, <16 x float> %src128_512, <16 x i32> <i32 0, i32 1, i32 2, i32 3, i32 4, i32 5, i32 6, i32 7, i32 16, i32 17, i32 18, i32 19, i32 20, i32 21, i32 22, i32 23>
-; SSE2-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: ret void
-;
-; SSSE3-LABEL: 'test_vXf32'
-; SSSE3-NEXT:  Cost Model: Found an estimated cost of 0 for instruction: %src64_128 = shufflevector <2 x float> %src64, <2 x float> undef, <4 x i32> <i32 0, i32 1, i32 poison, i32 poison>
-; SSSE3-NEXT:  Cost Model: Found an estimated cost of 0 for instruction: %src64_256 = shufflevector <2 x float> %src64, <2 x float> undef, <8 x i32> <i32 0, i32 1, i32 poison, i32 poison, i32 poison, i32 poison, i32 poison, i32 poison>
-; SSSE3-NEXT:  Cost Model: Found an estimated cost of 0 for instruction: %src64_512 = shufflevector <2 x float> %src64, <2 x float> undef, <16 x i32> <i32 0, i32 1, i32 poison, i32 poison, i32 poison, i32 poison, i32 poison, i32 poison, i32 poison, i32 poison, i32 poison, i32 poison, i32 poison, i32 poison, i32 poison, i32 poison>
-; SSSE3-NEXT:  Cost Model: Found an estimated cost of 0 for instruction: %src128_256 = shufflevector <4 x float> %src128, <4 x float> undef, <8 x i32> <i32 0, i32 1, i32 2, i32 3, i32 poison, i32 poison, i32 poison, i32 poison>
-; SSSE3-NEXT:  Cost Model: Found an estimated cost of 0 for instruction: %src128_512 = shufflevector <4 x float> %src128, <4 x float> undef, <16 x i32> <i32 0, i32 1, i32 2, i32 3, i32 poison, i32 poison, i32 poison, i32 poison, i32 poison, i32 poison, i32 poison, i32 poison, i32 poison, i32 poison, i32 poison, i32 poison>
-; SSSE3-NEXT:  Cost Model: Found an estimated cost of 0 for instruction: %src256_512 = shufflevector <8 x float> %src256, <8 x float> undef, <16 x i32> <i32 0, i32 1, i32 2, i32 3, i32 4, i32 5, i32 6, i32 7, i32 poison, i32 poison, i32 poison, i32 poison, i32 poison, i32 poison, i32 poison, i32 poison>
-; SSSE3-NEXT:  Cost Model: Found an estimated cost of 2 for instruction: %V128_01 = shufflevector <4 x float> %src128, <4 x float> %src64_128, <4 x i32> <i32 4, i32 5, i32 2, i32 3>
-; SSSE3-NEXT:  Cost Model: Found an estimated cost of 2 for instruction: %V128_23 = shufflevector <4 x float> %src128, <4 x float> %src64_128, <4 x i32> <i32 0, i32 1, i32 4, i32 5>
-; SSSE3-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %V256_01 = shufflevector <8 x float> %src256, <8 x float> %src64_256, <8 x i32> <i32 8, i32 9, i32 2, i32 3, i32 4, i32 5, i32 6, i32 7>
-; SSSE3-NEXT:  Cost Model: Found an estimated cost of 2 for instruction: %V256_23 = shufflevector <8 x float> %src256, <8 x float> %src6...
[truncated]

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llvmbot commented Jan 6, 2025

@llvm/pr-subscribers-backend-x86

Author: Simon Pilgrim (RKSimon)

Changes

Avoid always assuming the worst for v4f32 2 input shuffles, and match the SHUFPS pattern where possible - each pair of output elements must come from the same source register.

Patch is 159.92 KiB, truncated to 20.00 KiB below, full version: https://github.com/llvm/llvm-project/pull/121778.diff

14 Files Affected:

  • (modified) llvm/lib/Target/X86/X86TargetTransformInfo.cpp (+10-1)
  • (modified) llvm/test/Analysis/CostModel/X86/alternate-shuffle-cost.ll (+3-15)
  • (modified) llvm/test/Analysis/CostModel/X86/reduction.ll (+8-8)
  • (modified) llvm/test/Analysis/CostModel/X86/shuffle-insert_subvector-codesize.ll (+32-94)
  • (modified) llvm/test/Analysis/CostModel/X86/shuffle-insert_subvector-latency.ll (+32-94)
  • (modified) llvm/test/Analysis/CostModel/X86/shuffle-insert_subvector-sizelatency.ll (+32-94)
  • (modified) llvm/test/Analysis/CostModel/X86/shuffle-insert_subvector.ll (+32-94)
  • (modified) llvm/test/Analysis/CostModel/X86/shuffle-splice-codesize.ll (+1-1)
  • (modified) llvm/test/Analysis/CostModel/X86/shuffle-splice-latency.ll (+1-1)
  • (modified) llvm/test/Analysis/CostModel/X86/shuffle-splice-sizelatency.ll (+1-1)
  • (modified) llvm/test/Analysis/CostModel/X86/shuffle-splice.ll (+1-1)
  • (modified) llvm/test/Transforms/PhaseOrdering/X86/hadd.ll (+13-31)
  • (modified) llvm/test/Transforms/PhaseOrdering/X86/hsub.ll (+13-31)
  • (modified) llvm/test/Transforms/VectorCombine/X86/shuffle-of-cmps.ll (+7-23)
diff --git a/llvm/lib/Target/X86/X86TargetTransformInfo.cpp b/llvm/lib/Target/X86/X86TargetTransformInfo.cpp
index 5d07507457eec5..7a7554cdb99088 100644
--- a/llvm/lib/Target/X86/X86TargetTransformInfo.cpp
+++ b/llvm/lib/Target/X86/X86TargetTransformInfo.cpp
@@ -2226,9 +2226,18 @@ InstructionCost X86TTIImpl::getShuffleCost(
     { TTI::SK_PermuteTwoSrc,    MVT::v4f32, 2 }, // 2*shufps
   };
 
-  if (ST->hasSSE1())
+  if (ST->hasSSE1()) {
+    if (LT.first == 1 && LT.second == MVT::v4f32 && Mask.size() == 4) {
+      // SHUFPS: both pairs must come from the same source register.
+      auto MatchSHUFPS = [](int X, int Y) {
+        return X < 0 || Y < 0 || ((X & 4) == (Y & 4));
+      };
+      if (MatchSHUFPS(Mask[0], Mask[1]) && MatchSHUFPS(Mask[2], Mask[3]))
+        return 1;
+    }
     if (const auto *Entry = CostTableLookup(SSE1ShuffleTbl, Kind, LT.second))
       return LT.first * Entry->Cost;
+  }
 
   return BaseT::getShuffleCost(Kind, BaseTp, Mask, CostKind, Index, SubTp);
 }
diff --git a/llvm/test/Analysis/CostModel/X86/alternate-shuffle-cost.ll b/llvm/test/Analysis/CostModel/X86/alternate-shuffle-cost.ll
index 21a92c45591718..033537d93bf777 100644
--- a/llvm/test/Analysis/CostModel/X86/alternate-shuffle-cost.ll
+++ b/llvm/test/Analysis/CostModel/X86/alternate-shuffle-cost.ll
@@ -247,21 +247,9 @@ define <4 x float> @test_v4f32_2(<4 x float> %a, <4 x float> %b) {
 }
 
 define <4 x float> @test_v4f32_3(<4 x float> %a, <4 x float> %b) {
-; SSE2-LABEL: 'test_v4f32_3'
-; SSE2-NEXT:  Cost Model: Found an estimated cost of 2 for instruction: %1 = shufflevector <4 x float> %a, <4 x float> %b, <4 x i32> <i32 4, i32 5, i32 2, i32 3>
-; SSE2-NEXT:  Cost Model: Found an estimated cost of 0 for instruction: ret <4 x float> %1
-;
-; SSSE3-LABEL: 'test_v4f32_3'
-; SSSE3-NEXT:  Cost Model: Found an estimated cost of 2 for instruction: %1 = shufflevector <4 x float> %a, <4 x float> %b, <4 x i32> <i32 4, i32 5, i32 2, i32 3>
-; SSSE3-NEXT:  Cost Model: Found an estimated cost of 0 for instruction: ret <4 x float> %1
-;
-; SSE42-LABEL: 'test_v4f32_3'
-; SSE42-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %1 = shufflevector <4 x float> %a, <4 x float> %b, <4 x i32> <i32 4, i32 5, i32 2, i32 3>
-; SSE42-NEXT:  Cost Model: Found an estimated cost of 0 for instruction: ret <4 x float> %1
-;
-; AVX-LABEL: 'test_v4f32_3'
-; AVX-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %1 = shufflevector <4 x float> %a, <4 x float> %b, <4 x i32> <i32 4, i32 5, i32 2, i32 3>
-; AVX-NEXT:  Cost Model: Found an estimated cost of 0 for instruction: ret <4 x float> %1
+; CHECK-LABEL: 'test_v4f32_3'
+; CHECK-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %1 = shufflevector <4 x float> %a, <4 x float> %b, <4 x i32> <i32 4, i32 5, i32 2, i32 3>
+; CHECK-NEXT:  Cost Model: Found an estimated cost of 0 for instruction: ret <4 x float> %1
 ;
   %1 = shufflevector <4 x float> %a, <4 x float> %b, <4 x i32> <i32 4, i32 5, i32 2, i32 3>
   ret <4 x float> %1
diff --git a/llvm/test/Analysis/CostModel/X86/reduction.ll b/llvm/test/Analysis/CostModel/X86/reduction.ll
index c55545998d57f6..d7cf8e6cb8905b 100644
--- a/llvm/test/Analysis/CostModel/X86/reduction.ll
+++ b/llvm/test/Analysis/CostModel/X86/reduction.ll
@@ -926,8 +926,8 @@ define fastcc double @pairwise_reduction4double(<4 x double> %rdx, double %f1) {
 
 define fastcc float @pairwise_reduction8float(<8 x float> %rdx, float %f1) {
 ; SSE2-LABEL: 'pairwise_reduction8float'
-; SSE2-NEXT:  Cost Model: Found an estimated cost of 2 for instruction: %rdx.shuf.0.0 = shufflevector <8 x float> %rdx, <8 x float> undef, <8 x i32> <i32 0, i32 2, i32 4, i32 6, i32 poison, i32 poison, i32 poison, i32 poison>
-; SSE2-NEXT:  Cost Model: Found an estimated cost of 2 for instruction: %rdx.shuf.0.1 = shufflevector <8 x float> %rdx, <8 x float> undef, <8 x i32> <i32 1, i32 3, i32 5, i32 7, i32 poison, i32 poison, i32 poison, i32 poison>
+; SSE2-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %rdx.shuf.0.0 = shufflevector <8 x float> %rdx, <8 x float> undef, <8 x i32> <i32 0, i32 2, i32 4, i32 6, i32 poison, i32 poison, i32 poison, i32 poison>
+; SSE2-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %rdx.shuf.0.1 = shufflevector <8 x float> %rdx, <8 x float> undef, <8 x i32> <i32 1, i32 3, i32 5, i32 7, i32 poison, i32 poison, i32 poison, i32 poison>
 ; SSE2-NEXT:  Cost Model: Found an estimated cost of 4 for instruction: %bin.rdx = fadd <8 x float> %rdx.shuf.0.0, %rdx.shuf.0.1
 ; SSE2-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %rdx.shuf.1.0 = shufflevector <8 x float> %bin.rdx, <8 x float> undef, <8 x i32> <i32 0, i32 2, i32 poison, i32 poison, i32 poison, i32 poison, i32 poison, i32 poison>
 ; SSE2-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %rdx.shuf.1.1 = shufflevector <8 x float> %bin.rdx, <8 x float> undef, <8 x i32> <i32 1, i32 3, i32 poison, i32 poison, i32 poison, i32 poison, i32 poison, i32 poison>
@@ -939,8 +939,8 @@ define fastcc float @pairwise_reduction8float(<8 x float> %rdx, float %f1) {
 ; SSE2-NEXT:  Cost Model: Found an estimated cost of 0 for instruction: ret float %r
 ;
 ; SSSE3-LABEL: 'pairwise_reduction8float'
-; SSSE3-NEXT:  Cost Model: Found an estimated cost of 2 for instruction: %rdx.shuf.0.0 = shufflevector <8 x float> %rdx, <8 x float> undef, <8 x i32> <i32 0, i32 2, i32 4, i32 6, i32 poison, i32 poison, i32 poison, i32 poison>
-; SSSE3-NEXT:  Cost Model: Found an estimated cost of 2 for instruction: %rdx.shuf.0.1 = shufflevector <8 x float> %rdx, <8 x float> undef, <8 x i32> <i32 1, i32 3, i32 5, i32 7, i32 poison, i32 poison, i32 poison, i32 poison>
+; SSSE3-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %rdx.shuf.0.0 = shufflevector <8 x float> %rdx, <8 x float> undef, <8 x i32> <i32 0, i32 2, i32 4, i32 6, i32 poison, i32 poison, i32 poison, i32 poison>
+; SSSE3-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %rdx.shuf.0.1 = shufflevector <8 x float> %rdx, <8 x float> undef, <8 x i32> <i32 1, i32 3, i32 5, i32 7, i32 poison, i32 poison, i32 poison, i32 poison>
 ; SSSE3-NEXT:  Cost Model: Found an estimated cost of 4 for instruction: %bin.rdx = fadd <8 x float> %rdx.shuf.0.0, %rdx.shuf.0.1
 ; SSSE3-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %rdx.shuf.1.0 = shufflevector <8 x float> %bin.rdx, <8 x float> undef, <8 x i32> <i32 0, i32 2, i32 poison, i32 poison, i32 poison, i32 poison, i32 poison, i32 poison>
 ; SSSE3-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %rdx.shuf.1.1 = shufflevector <8 x float> %bin.rdx, <8 x float> undef, <8 x i32> <i32 1, i32 3, i32 poison, i32 poison, i32 poison, i32 poison, i32 poison, i32 poison>
@@ -952,8 +952,8 @@ define fastcc float @pairwise_reduction8float(<8 x float> %rdx, float %f1) {
 ; SSSE3-NEXT:  Cost Model: Found an estimated cost of 0 for instruction: ret float %r
 ;
 ; SSE42-LABEL: 'pairwise_reduction8float'
-; SSE42-NEXT:  Cost Model: Found an estimated cost of 2 for instruction: %rdx.shuf.0.0 = shufflevector <8 x float> %rdx, <8 x float> undef, <8 x i32> <i32 0, i32 2, i32 4, i32 6, i32 poison, i32 poison, i32 poison, i32 poison>
-; SSE42-NEXT:  Cost Model: Found an estimated cost of 2 for instruction: %rdx.shuf.0.1 = shufflevector <8 x float> %rdx, <8 x float> undef, <8 x i32> <i32 1, i32 3, i32 5, i32 7, i32 poison, i32 poison, i32 poison, i32 poison>
+; SSE42-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %rdx.shuf.0.0 = shufflevector <8 x float> %rdx, <8 x float> undef, <8 x i32> <i32 0, i32 2, i32 4, i32 6, i32 poison, i32 poison, i32 poison, i32 poison>
+; SSE42-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %rdx.shuf.0.1 = shufflevector <8 x float> %rdx, <8 x float> undef, <8 x i32> <i32 1, i32 3, i32 5, i32 7, i32 poison, i32 poison, i32 poison, i32 poison>
 ; SSE42-NEXT:  Cost Model: Found an estimated cost of 2 for instruction: %bin.rdx = fadd <8 x float> %rdx.shuf.0.0, %rdx.shuf.0.1
 ; SSE42-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %rdx.shuf.1.0 = shufflevector <8 x float> %bin.rdx, <8 x float> undef, <8 x i32> <i32 0, i32 2, i32 poison, i32 poison, i32 poison, i32 poison, i32 poison, i32 poison>
 ; SSE42-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %rdx.shuf.1.1 = shufflevector <8 x float> %bin.rdx, <8 x float> undef, <8 x i32> <i32 1, i32 3, i32 poison, i32 poison, i32 poison, i32 poison, i32 poison, i32 poison>
@@ -991,8 +991,8 @@ define fastcc float @pairwise_reduction8float(<8 x float> %rdx, float %f1) {
 ; AVX2-NEXT:  Cost Model: Found an estimated cost of 0 for instruction: ret float %r
 ;
 ; SLM-LABEL: 'pairwise_reduction8float'
-; SLM-NEXT:  Cost Model: Found an estimated cost of 2 for instruction: %rdx.shuf.0.0 = shufflevector <8 x float> %rdx, <8 x float> undef, <8 x i32> <i32 0, i32 2, i32 4, i32 6, i32 poison, i32 poison, i32 poison, i32 poison>
-; SLM-NEXT:  Cost Model: Found an estimated cost of 2 for instruction: %rdx.shuf.0.1 = shufflevector <8 x float> %rdx, <8 x float> undef, <8 x i32> <i32 1, i32 3, i32 5, i32 7, i32 poison, i32 poison, i32 poison, i32 poison>
+; SLM-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %rdx.shuf.0.0 = shufflevector <8 x float> %rdx, <8 x float> undef, <8 x i32> <i32 0, i32 2, i32 4, i32 6, i32 poison, i32 poison, i32 poison, i32 poison>
+; SLM-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %rdx.shuf.0.1 = shufflevector <8 x float> %rdx, <8 x float> undef, <8 x i32> <i32 1, i32 3, i32 5, i32 7, i32 poison, i32 poison, i32 poison, i32 poison>
 ; SLM-NEXT:  Cost Model: Found an estimated cost of 2 for instruction: %bin.rdx = fadd <8 x float> %rdx.shuf.0.0, %rdx.shuf.0.1
 ; SLM-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %rdx.shuf.1.0 = shufflevector <8 x float> %bin.rdx, <8 x float> undef, <8 x i32> <i32 0, i32 2, i32 poison, i32 poison, i32 poison, i32 poison, i32 poison, i32 poison>
 ; SLM-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %rdx.shuf.1.1 = shufflevector <8 x float> %bin.rdx, <8 x float> undef, <8 x i32> <i32 1, i32 3, i32 poison, i32 poison, i32 poison, i32 poison, i32 poison, i32 poison>
diff --git a/llvm/test/Analysis/CostModel/X86/shuffle-insert_subvector-codesize.ll b/llvm/test/Analysis/CostModel/X86/shuffle-insert_subvector-codesize.ll
index bcba890867ed21..11ee433cae26c2 100644
--- a/llvm/test/Analysis/CostModel/X86/shuffle-insert_subvector-codesize.ll
+++ b/llvm/test/Analysis/CostModel/X86/shuffle-insert_subvector-codesize.ll
@@ -133,98 +133,36 @@ define void @test_vXi64(<2 x i64> %src128, <4 x i64> %src256, <8 x i64> %src512)
 }
 
 define void @test_vXf32(<2 x float> %src64, <4 x float> %src128, <8 x float> %src256, <16 x float> %src512) {
-; SSE2-LABEL: 'test_vXf32'
-; SSE2-NEXT:  Cost Model: Found an estimated cost of 0 for instruction: %src64_128 = shufflevector <2 x float> %src64, <2 x float> undef, <4 x i32> <i32 0, i32 1, i32 poison, i32 poison>
-; SSE2-NEXT:  Cost Model: Found an estimated cost of 0 for instruction: %src64_256 = shufflevector <2 x float> %src64, <2 x float> undef, <8 x i32> <i32 0, i32 1, i32 poison, i32 poison, i32 poison, i32 poison, i32 poison, i32 poison>
-; SSE2-NEXT:  Cost Model: Found an estimated cost of 0 for instruction: %src64_512 = shufflevector <2 x float> %src64, <2 x float> undef, <16 x i32> <i32 0, i32 1, i32 poison, i32 poison, i32 poison, i32 poison, i32 poison, i32 poison, i32 poison, i32 poison, i32 poison, i32 poison, i32 poison, i32 poison, i32 poison, i32 poison>
-; SSE2-NEXT:  Cost Model: Found an estimated cost of 0 for instruction: %src128_256 = shufflevector <4 x float> %src128, <4 x float> undef, <8 x i32> <i32 0, i32 1, i32 2, i32 3, i32 poison, i32 poison, i32 poison, i32 poison>
-; SSE2-NEXT:  Cost Model: Found an estimated cost of 0 for instruction: %src128_512 = shufflevector <4 x float> %src128, <4 x float> undef, <16 x i32> <i32 0, i32 1, i32 2, i32 3, i32 poison, i32 poison, i32 poison, i32 poison, i32 poison, i32 poison, i32 poison, i32 poison, i32 poison, i32 poison, i32 poison, i32 poison>
-; SSE2-NEXT:  Cost Model: Found an estimated cost of 0 for instruction: %src256_512 = shufflevector <8 x float> %src256, <8 x float> undef, <16 x i32> <i32 0, i32 1, i32 2, i32 3, i32 4, i32 5, i32 6, i32 7, i32 poison, i32 poison, i32 poison, i32 poison, i32 poison, i32 poison, i32 poison, i32 poison>
-; SSE2-NEXT:  Cost Model: Found an estimated cost of 2 for instruction: %V128_01 = shufflevector <4 x float> %src128, <4 x float> %src64_128, <4 x i32> <i32 4, i32 5, i32 2, i32 3>
-; SSE2-NEXT:  Cost Model: Found an estimated cost of 2 for instruction: %V128_23 = shufflevector <4 x float> %src128, <4 x float> %src64_128, <4 x i32> <i32 0, i32 1, i32 4, i32 5>
-; SSE2-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %V256_01 = shufflevector <8 x float> %src256, <8 x float> %src64_256, <8 x i32> <i32 8, i32 9, i32 2, i32 3, i32 4, i32 5, i32 6, i32 7>
-; SSE2-NEXT:  Cost Model: Found an estimated cost of 2 for instruction: %V256_23 = shufflevector <8 x float> %src256, <8 x float> %src64_256, <8 x i32> <i32 0, i32 1, i32 8, i32 9, i32 4, i32 5, i32 6, i32 7>
-; SSE2-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %V256_45 = shufflevector <8 x float> %src256, <8 x float> %src64_256, <8 x i32> <i32 0, i32 1, i32 2, i32 3, i32 8, i32 9, i32 6, i32 7>
-; SSE2-NEXT:  Cost Model: Found an estimated cost of 2 for instruction: %V256_67 = shufflevector <8 x float> %src256, <8 x float> %src64_256, <8 x i32> <i32 0, i32 1, i32 2, i32 3, i32 4, i32 5, i32 8, i32 9>
-; SSE2-NEXT:  Cost Model: Found an estimated cost of 0 for instruction: %V256_0123 = shufflevector <8 x float> %src256, <8 x float> %src128_256, <8 x i32> <i32 8, i32 9, i32 10, i32 11, i32 4, i32 5, i32 6, i32 7>
-; SSE2-NEXT:  Cost Model: Found an estimated cost of 0 for instruction: %V256_4567 = shufflevector <8 x float> %src256, <8 x float> %src128_256, <8 x i32> <i32 0, i32 1, i32 2, i32 3, i32 8, i32 9, i32 10, i32 11>
-; SSE2-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %V512_01 = shufflevector <16 x float> %src512, <16 x float> %src64_512, <16 x i32> <i32 16, i32 17, i32 2, i32 3, i32 4, i32 5, i32 6, i32 7, i32 8, i32 9, i32 10, i32 11, i32 12, i32 13, i32 14, i32 15>
-; SSE2-NEXT:  Cost Model: Found an estimated cost of 2 for instruction: %V512_23 = shufflevector <16 x float> %src512, <16 x float> %src64_512, <16 x i32> <i32 0, i32 1, i32 16, i32 17, i32 4, i32 5, i32 6, i32 7, i32 8, i32 9, i32 10, i32 11, i32 12, i32 13, i32 14, i32 15>
-; SSE2-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %V512_45 = shufflevector <16 x float> %src512, <16 x float> %src64_512, <16 x i32> <i32 0, i32 1, i32 2, i32 3, i32 16, i32 17, i32 6, i32 7, i32 8, i32 9, i32 10, i32 11, i32 12, i32 13, i32 14, i32 15>
-; SSE2-NEXT:  Cost Model: Found an estimated cost of 2 for instruction: %V512_67 = shufflevector <16 x float> %src512, <16 x float> %src64_512, <16 x i32> <i32 0, i32 1, i32 2, i32 3, i32 4, i32 5, i32 16, i32 17, i32 8, i32 9, i32 10, i32 11, i32 12, i32 13, i32 14, i32 15>
-; SSE2-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %V512_89 = shufflevector <16 x float> %src512, <16 x float> %src64_512, <16 x i32> <i32 0, i32 1, i32 2, i32 3, i32 4, i32 5, i32 6, i32 7, i32 16, i32 17, i32 10, i32 11, i32 12, i32 13, i32 14, i32 15>
-; SSE2-NEXT:  Cost Model: Found an estimated cost of 2 for instruction: %V512_AB = shufflevector <16 x float> %src512, <16 x float> %src64_512, <16 x i32> <i32 0, i32 1, i32 2, i32 3, i32 4, i32 5, i32 6, i32 7, i32 8, i32 9, i32 16, i32 17, i32 12, i32 13, i32 14, i32 15>
-; SSE2-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %V512_CD = shufflevector <16 x float> %src512, <16 x float> %src64_512, <16 x i32> <i32 0, i32 1, i32 2, i32 3, i32 4, i32 5, i32 6, i32 7, i32 8, i32 9, i32 10, i32 11, i32 16, i32 17, i32 14, i32 15>
-; SSE2-NEXT:  Cost Model: Found an estimated cost of 2 for instruction: %V512_EF = shufflevector <16 x float> %src512, <16 x float> %src64_512, <16 x i32> <i32 0, i32 1, i32 2, i32 3, i32 4, i32 5, i32 6, i32 7, i32 8, i32 9, i32 10, i32 11, i32 12, i32 13, i32 16, i32 17>
-; SSE2-NEXT:  Cost Model: Found an estimated cost of 0 for instruction: %V512_0123 = shufflevector <16 x float> %src512, <16 x float> %src128_512, <16 x i32> <i32 16, i32 17, i32 18, i32 19, i32 4, i32 5, i32 6, i32 7, i32 8, i32 9, i32 10, i32 11, i32 12, i32 13, i32 14, i32 15>
-; SSE2-NEXT:  Cost Model: Found an estimated cost of 0 for instruction: %V512_4567 = shufflevector <16 x float> %src512, <16 x float> %src128_512, <16 x i32> <i32 0, i32 1, i32 2, i32 3, i32 16, i32 17, i32 18, i32 19, i32 8, i32 9, i32 10, i32 11, i32 12, i32 13, i32 14, i32 15>
-; SSE2-NEXT:  Cost Model: Found an estimated cost of 0 for instruction: %V512_89AB = shufflevector <16 x float> %src512, <16 x float> %src128_512, <16 x i32> <i32 0, i32 1, i32 2, i32 3, i32 4, i32 5, i32 6, i32 7, i32 16, i32 17, i32 18, i32 19, i32 12, i32 13, i32 14, i32 15>
-; SSE2-NEXT:  Cost Model: Found an estimated cost of 0 for instruction: %V512_CDEF = shufflevector <16 x float> %src512, <16 x float> %src128_512, <16 x i32> <i32 0, i32 1, i32 2, i32 3, i32 4, i32 5, i32 6, i32 7, i32 8, i32 9, i32 10, i32 11, i32 16, i32 17, i32 18, i32 19>
-; SSE2-NEXT:  Cost Model: Found an estimated cost of 0 for instruction: %V512_01234567 = shufflevector <16 x float> %src512, <16 x float> %src128_512, <16 x i32> <i32 16, i32 17, i32 18, i32 19, i32 20, i32 21, i32 22, i32 23, i32 8, i32 9, i32 10, i32 11, i32 12, i32 13, i32 14, i32 15>
-; SSE2-NEXT:  Cost Model: Found an estimated cost of 0 for instruction: %V512_89ABCDEF = shufflevector <16 x float> %src512, <16 x float> %src128_512, <16 x i32> <i32 0, i32 1, i32 2, i32 3, i32 4, i32 5, i32 6, i32 7, i32 16, i32 17, i32 18, i32 19, i32 20, i32 21, i32 22, i32 23>
-; SSE2-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: ret void
-;
-; SSSE3-LABEL: 'test_vXf32'
-; SSSE3-NEXT:  Cost Model: Found an estimated cost of 0 for instruction: %src64_128 = shufflevector <2 x float> %src64, <2 x float> undef, <4 x i32> <i32 0, i32 1, i32 poison, i32 poison>
-; SSSE3-NEXT:  Cost Model: Found an estimated cost of 0 for instruction: %src64_256 = shufflevector <2 x float> %src64, <2 x float> undef, <8 x i32> <i32 0, i32 1, i32 poison, i32 poison, i32 poison, i32 poison, i32 poison, i32 poison>
-; SSSE3-NEXT:  Cost Model: Found an estimated cost of 0 for instruction: %src64_512 = shufflevector <2 x float> %src64, <2 x float> undef, <16 x i32> <i32 0, i32 1, i32 poison, i32 poison, i32 poison, i32 poison, i32 poison, i32 poison, i32 poison, i32 poison, i32 poison, i32 poison, i32 poison, i32 poison, i32 poison, i32 poison>
-; SSSE3-NEXT:  Cost Model: Found an estimated cost of 0 for instruction: %src128_256 = shufflevector <4 x float> %src128, <4 x float> undef, <8 x i32> <i32 0, i32 1, i32 2, i32 3, i32 poison, i32 poison, i32 poison, i32 poison>
-; SSSE3-NEXT:  Cost Model: Found an estimated cost of 0 for instruction: %src128_512 = shufflevector <4 x float> %src128, <4 x float> undef, <16 x i32> <i32 0, i32 1, i32 2, i32 3, i32 poison, i32 poison, i32 poison, i32 poison, i32 poison, i32 poison, i32 poison, i32 poison, i32 poison, i32 poison, i32 poison, i32 poison>
-; SSSE3-NEXT:  Cost Model: Found an estimated cost of 0 for instruction: %src256_512 = shufflevector <8 x float> %src256, <8 x float> undef, <16 x i32> <i32 0, i32 1, i32 2, i32 3, i32 4, i32 5, i32 6, i32 7, i32 poison, i32 poison, i32 poison, i32 poison, i32 poison, i32 poison, i32 poison, i32 poison>
-; SSSE3-NEXT:  Cost Model: Found an estimated cost of 2 for instruction: %V128_01 = shufflevector <4 x float> %src128, <4 x float> %src64_128, <4 x i32> <i32 4, i32 5, i32 2, i32 3>
-; SSSE3-NEXT:  Cost Model: Found an estimated cost of 2 for instruction: %V128_23 = shufflevector <4 x float> %src128, <4 x float> %src64_128, <4 x i32> <i32 0, i32 1, i32 4, i32 5>
-; SSSE3-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %V256_01 = shufflevector <8 x float> %src256, <8 x float> %src64_256, <8 x i32> <i32 8, i32 9, i32 2, i32 3, i32 4, i32 5, i32 6, i32 7>
-; SSSE3-NEXT:  Cost Model: Found an estimated cost of 2 for instruction: %V256_23 = shufflevector <8 x float> %src256, <8 x float> %src6...
[truncated]

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github-actions bot commented Jan 6, 2025

⚠️ undef deprecator found issues in your code. ⚠️

You can test this locally with the following command: 
git diff -U0 --pickaxe-regex -S '([^a-zA-Z0-9#_-]undef[^a-zA-Z0-9_-]|UndefValue::get)' d993b11b86dcae75b582939337770eaf1c1a228b 5bf964e99ccc1766a39e4fab1118a00f875f5faa llvm/lib/Target/X86/X86TargetTransformInfo.cpp llvm/test/Analysis/CostModel/X86/alternate-shuffle-cost.ll llvm/test/Analysis/CostModel/X86/reduction.ll llvm/test/Analysis/CostModel/X86/shuffle-insert_subvector-codesize.ll llvm/test/Analysis/CostModel/X86/shuffle-insert_subvector-latency.ll llvm/test/Analysis/CostModel/X86/shuffle-insert_subvector-sizelatency.ll llvm/test/Analysis/CostModel/X86/shuffle-insert_subvector.ll llvm/test/Analysis/CostModel/X86/shuffle-splice-codesize.ll llvm/test/Analysis/CostModel/X86/shuffle-splice-latency.ll llvm/test/Analysis/CostModel/X86/shuffle-splice-sizelatency.ll llvm/test/Analysis/CostModel/X86/shuffle-splice.ll llvm/test/Transforms/PhaseOrdering/X86/hadd.ll llvm/test/Transforms/PhaseOrdering/X86/hsub.ll llvm/test/Transforms/VectorCombine/X86/shuffle-of-cmps.ll

The following files introduce new uses of undef:

  • llvm/test/Analysis/CostModel/X86/shuffle-insert_subvector-codesize.ll
  • llvm/test/Analysis/CostModel/X86/shuffle-insert_subvector-latency.ll
  • llvm/test/Analysis/CostModel/X86/shuffle-insert_subvector-sizelatency.ll
  • llvm/test/Analysis/CostModel/X86/shuffle-insert_subvector.ll

Undef is now deprecated and should only be used in the rare cases where no replacement is possible. For example, a load of uninitialized memory yields undef. You should use poison values for placeholders instead.

In tests, avoid using undef and having tests that trigger undefined behavior. If you need an operand with some unimportant value, you can add a new argument to the function and use that instead.

For example, this is considered a bad practice:

define void @fn() {
  ...
  br i1 undef, ...
}

Please use the following instead:

define void @fn(i1 %cond) {
  ...
  br i1 %cond, ...
}

Please refer to the Undefined Behavior Manual for more information.

alexey-bataev
alexey-bataev reviewed Jan 6, 2025
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llvm/lib/Target/X86/X86TargetTransformInfo.cpp
@@ -2226,9 +2226,18 @@ InstructionCost X86TTIImpl::getShuffleCost(
{ TTI::SK_PermuteTwoSrc, MVT::v4f32, 2 }, // 2*shufps
};

if (ST->hasSSE1())
if (ST->hasSSE1()) {
if (LT.first == 1 && LT.second == MVT::v4f32 && Mask.size() == 4) {
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@alexey-bataev alexey-bataev Jan 6, 2025 •
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What if BaseTp is not <4 x f32> and it is just promoted to MVT::v4f32, can it happen?

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Not for any element type other than f32, which is why I added the Mask.size check - I did consider supporting v2f32/v3f32 handling by widening the mask with PoisonMaskElem but didn't find much need for it - wdyt?

alexey-bataev
alexey-bataev approved these changes Jan 6, 2025
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LG

@RKSimon RKSimon merged commit db88071 into llvm:main Jan 6, 2025
11 of 12 checks passed
@RKSimon RKSimon deleted the x86-shufps-shuffle-cost branch January 6, 2025 17:54
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@alexey-bataev alexey-bataev alexey-bataev approved these changes

@phoebewang phoebewang Awaiting requested review from phoebewang

@KanRobert KanRobert Awaiting requested review from KanRobert

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