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[InstCombine] Add canonicalization of sitofp -> uitofp nneg #88299

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[InstCombine] Add canonicalization of sitofp -> uitofp nneg #88299

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This is essentially the same as #82404 but has the nneg flag which
allows the backend to reliably undo the transform.

@goldsteinn
[InstCombine] Add canonicalization of sitofp -> uitofp nneg
46f7665 
This is essentially the same as llvm#82404 but has the `nneg` flag which
allows the backend to reliably undo the transform.
@goldsteinn goldsteinn requested a review from nikic as a code owner April 10, 2024 17:16
@llvmbot llvmbot added clang Clang issues not falling into any other category llvm:transforms labels Apr 10, 2024
@goldsteinn goldsteinn requested a review from dtcxzyw April 10, 2024 17:17
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llvmbot commented Apr 10, 2024

@llvm/pr-subscribers-clang

Author: None (goldsteinn)

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This is essentially the same as #82404 but has the nneg flag which
allows the backend to reliably undo the transform.

Patch is 61.71 KiB, truncated to 20.00 KiB below, full version: https://github.com/llvm/llvm-project/pull/88299.diff

12 Files Affected:

  • (modified) clang/test/Headers/__clang_hip_math.hip (+12-12)
  • (modified) llvm/lib/Transforms/InstCombine/InstCombineCasts.cpp (+16-2)
  • (modified) llvm/test/Transforms/InstCombine/add-sitofp.ll (+10-10)
  • (modified) llvm/test/Transforms/InstCombine/binop-itofp.ll (+33-33)
  • (modified) llvm/test/Transforms/InstCombine/clamp-to-minmax.ll (+5-5)
  • (modified) llvm/test/Transforms/InstCombine/fpcast.ll (+12-12)
  • (modified) llvm/test/Transforms/InstCombine/minmax-fold.ll (+5-5)
  • (modified) llvm/test/Transforms/InstCombine/minmax-fp.ll (+1-1)
  • (modified) llvm/test/Transforms/InstCombine/pr27236.ll (+1-1)
  • (modified) llvm/test/Transforms/InstCombine/sitofp.ll (+1-1)
  • (modified) llvm/test/Transforms/LoopVectorize/X86/float-induction-x86.ll (+3-3)
  • (modified) llvm/test/Transforms/LoopVectorize/float-induction.ll (+28-28)
diff --git a/clang/test/Headers/__clang_hip_math.hip b/clang/test/Headers/__clang_hip_math.hip
index 37099de74fb8ec..bff1708120604b 100644
--- a/clang/test/Headers/__clang_hip_math.hip
+++ b/clang/test/Headers/__clang_hip_math.hip
@@ -1685,7 +1685,7 @@ extern "C" __device__ double test_j1(double x) {
 // DEFAULT-NEXT:    [[__X1_0_I3:%.*]] = phi float [ [[SUB_I:%.*]], [[FOR_BODY_I]] ], [ [[CALL_I21_I]], [[IF_END4_I]] ]
 // DEFAULT-NEXT:    [[__X0_0_I2:%.*]] = phi float [ [[__X1_0_I3]], [[FOR_BODY_I]] ], [ [[CALL_I_I]], [[IF_END4_I]] ]
 // DEFAULT-NEXT:    [[MUL_I:%.*]] = shl nuw nsw i32 [[__I_0_I4]], 1
-// DEFAULT-NEXT:    [[CONV_I:%.*]] = sitofp i32 [[MUL_I]] to float
+// DEFAULT-NEXT:    [[CONV_I:%.*]] = uitofp nneg i32 [[MUL_I]] to float
 // DEFAULT-NEXT:    [[DIV_I:%.*]] = fdiv contract float [[CONV_I]], [[Y]]
 // DEFAULT-NEXT:    [[MUL8_I:%.*]] = fmul contract float [[__X1_0_I3]], [[DIV_I]]
 // DEFAULT-NEXT:    [[SUB_I]] = fsub contract float [[MUL8_I]], [[__X0_0_I2]]
@@ -1718,7 +1718,7 @@ extern "C" __device__ double test_j1(double x) {
 // FINITEONLY-NEXT:    [[__X1_0_I3:%.*]] = phi float [ [[SUB_I:%.*]], [[FOR_BODY_I]] ], [ [[CALL_I21_I]], [[IF_END4_I]] ]
 // FINITEONLY-NEXT:    [[__X0_0_I2:%.*]] = phi float [ [[__X1_0_I3]], [[FOR_BODY_I]] ], [ [[CALL_I_I]], [[IF_END4_I]] ]
 // FINITEONLY-NEXT:    [[MUL_I:%.*]] = shl nuw nsw i32 [[__I_0_I4]], 1
-// FINITEONLY-NEXT:    [[CONV_I:%.*]] = sitofp i32 [[MUL_I]] to float
+// FINITEONLY-NEXT:    [[CONV_I:%.*]] = uitofp nneg i32 [[MUL_I]] to float
 // FINITEONLY-NEXT:    [[DIV_I:%.*]] = fdiv nnan ninf contract float [[CONV_I]], [[Y]]
 // FINITEONLY-NEXT:    [[MUL8_I:%.*]] = fmul nnan ninf contract float [[__X1_0_I3]], [[DIV_I]]
 // FINITEONLY-NEXT:    [[SUB_I]] = fsub nnan ninf contract float [[MUL8_I]], [[__X0_0_I2]]
@@ -1751,7 +1751,7 @@ extern "C" __device__ double test_j1(double x) {
 // APPROX-NEXT:    [[__X1_0_I3:%.*]] = phi float [ [[SUB_I:%.*]], [[FOR_BODY_I]] ], [ [[CALL_I21_I]], [[IF_END4_I]] ]
 // APPROX-NEXT:    [[__X0_0_I2:%.*]] = phi float [ [[__X1_0_I3]], [[FOR_BODY_I]] ], [ [[CALL_I_I]], [[IF_END4_I]] ]
 // APPROX-NEXT:    [[MUL_I:%.*]] = shl nuw nsw i32 [[__I_0_I4]], 1
-// APPROX-NEXT:    [[CONV_I:%.*]] = sitofp i32 [[MUL_I]] to float
+// APPROX-NEXT:    [[CONV_I:%.*]] = uitofp nneg i32 [[MUL_I]] to float
 // APPROX-NEXT:    [[DIV_I:%.*]] = fdiv contract float [[CONV_I]], [[Y]]
 // APPROX-NEXT:    [[MUL8_I:%.*]] = fmul contract float [[__X1_0_I3]], [[DIV_I]]
 // APPROX-NEXT:    [[SUB_I]] = fsub contract float [[MUL8_I]], [[__X0_0_I2]]
@@ -1788,7 +1788,7 @@ extern "C" __device__ float test_jnf(int x, float y) {
 // DEFAULT-NEXT:    [[__X1_0_I3:%.*]] = phi double [ [[SUB_I:%.*]], [[FOR_BODY_I]] ], [ [[CALL_I21_I]], [[IF_END4_I]] ]
 // DEFAULT-NEXT:    [[__X0_0_I2:%.*]] = phi double [ [[__X1_0_I3]], [[FOR_BODY_I]] ], [ [[CALL_I_I]], [[IF_END4_I]] ]
 // DEFAULT-NEXT:    [[MUL_I:%.*]] = shl nuw nsw i32 [[__I_0_I4]], 1
-// DEFAULT-NEXT:    [[CONV_I:%.*]] = sitofp i32 [[MUL_I]] to double
+// DEFAULT-NEXT:    [[CONV_I:%.*]] = uitofp nneg i32 [[MUL_I]] to double
 // DEFAULT-NEXT:    [[DIV_I:%.*]] = fdiv contract double [[CONV_I]], [[Y]]
 // DEFAULT-NEXT:    [[MUL8_I:%.*]] = fmul contract double [[__X1_0_I3]], [[DIV_I]]
 // DEFAULT-NEXT:    [[SUB_I]] = fsub contract double [[MUL8_I]], [[__X0_0_I2]]
@@ -1821,7 +1821,7 @@ extern "C" __device__ float test_jnf(int x, float y) {
 // FINITEONLY-NEXT:    [[__X1_0_I3:%.*]] = phi double [ [[SUB_I:%.*]], [[FOR_BODY_I]] ], [ [[CALL_I21_I]], [[IF_END4_I]] ]
 // FINITEONLY-NEXT:    [[__X0_0_I2:%.*]] = phi double [ [[__X1_0_I3]], [[FOR_BODY_I]] ], [ [[CALL_I_I]], [[IF_END4_I]] ]
 // FINITEONLY-NEXT:    [[MUL_I:%.*]] = shl nuw nsw i32 [[__I_0_I4]], 1
-// FINITEONLY-NEXT:    [[CONV_I:%.*]] = sitofp i32 [[MUL_I]] to double
+// FINITEONLY-NEXT:    [[CONV_I:%.*]] = uitofp nneg i32 [[MUL_I]] to double
 // FINITEONLY-NEXT:    [[DIV_I:%.*]] = fdiv nnan ninf contract double [[CONV_I]], [[Y]]
 // FINITEONLY-NEXT:    [[MUL8_I:%.*]] = fmul nnan ninf contract double [[__X1_0_I3]], [[DIV_I]]
 // FINITEONLY-NEXT:    [[SUB_I]] = fsub nnan ninf contract double [[MUL8_I]], [[__X0_0_I2]]
@@ -1854,7 +1854,7 @@ extern "C" __device__ float test_jnf(int x, float y) {
 // APPROX-NEXT:    [[__X1_0_I3:%.*]] = phi double [ [[SUB_I:%.*]], [[FOR_BODY_I]] ], [ [[CALL_I21_I]], [[IF_END4_I]] ]
 // APPROX-NEXT:    [[__X0_0_I2:%.*]] = phi double [ [[__X1_0_I3]], [[FOR_BODY_I]] ], [ [[CALL_I_I]], [[IF_END4_I]] ]
 // APPROX-NEXT:    [[MUL_I:%.*]] = shl nuw nsw i32 [[__I_0_I4]], 1
-// APPROX-NEXT:    [[CONV_I:%.*]] = sitofp i32 [[MUL_I]] to double
+// APPROX-NEXT:    [[CONV_I:%.*]] = uitofp nneg i32 [[MUL_I]] to double
 // APPROX-NEXT:    [[DIV_I:%.*]] = fdiv contract double [[CONV_I]], [[Y]]
 // APPROX-NEXT:    [[MUL8_I:%.*]] = fmul contract double [[__X1_0_I3]], [[DIV_I]]
 // APPROX-NEXT:    [[SUB_I]] = fsub contract double [[MUL8_I]], [[__X0_0_I2]]
@@ -4222,7 +4222,7 @@ extern "C" __device__ double test_y1(double x) {
 // DEFAULT-NEXT:    [[__X1_0_I3:%.*]] = phi float [ [[SUB_I:%.*]], [[FOR_BODY_I]] ], [ [[CALL_I21_I]], [[IF_END4_I]] ]
 // DEFAULT-NEXT:    [[__X0_0_I2:%.*]] = phi float [ [[__X1_0_I3]], [[FOR_BODY_I]] ], [ [[CALL_I_I]], [[IF_END4_I]] ]
 // DEFAULT-NEXT:    [[MUL_I:%.*]] = shl nuw nsw i32 [[__I_0_I4]], 1
-// DEFAULT-NEXT:    [[CONV_I:%.*]] = sitofp i32 [[MUL_I]] to float
+// DEFAULT-NEXT:    [[CONV_I:%.*]] = uitofp nneg i32 [[MUL_I]] to float
 // DEFAULT-NEXT:    [[DIV_I:%.*]] = fdiv contract float [[CONV_I]], [[Y]]
 // DEFAULT-NEXT:    [[MUL8_I:%.*]] = fmul contract float [[__X1_0_I3]], [[DIV_I]]
 // DEFAULT-NEXT:    [[SUB_I]] = fsub contract float [[MUL8_I]], [[__X0_0_I2]]
@@ -4255,7 +4255,7 @@ extern "C" __device__ double test_y1(double x) {
 // FINITEONLY-NEXT:    [[__X1_0_I3:%.*]] = phi float [ [[SUB_I:%.*]], [[FOR_BODY_I]] ], [ [[CALL_I21_I]], [[IF_END4_I]] ]
 // FINITEONLY-NEXT:    [[__X0_0_I2:%.*]] = phi float [ [[__X1_0_I3]], [[FOR_BODY_I]] ], [ [[CALL_I_I]], [[IF_END4_I]] ]
 // FINITEONLY-NEXT:    [[MUL_I:%.*]] = shl nuw nsw i32 [[__I_0_I4]], 1
-// FINITEONLY-NEXT:    [[CONV_I:%.*]] = sitofp i32 [[MUL_I]] to float
+// FINITEONLY-NEXT:    [[CONV_I:%.*]] = uitofp nneg i32 [[MUL_I]] to float
 // FINITEONLY-NEXT:    [[DIV_I:%.*]] = fdiv nnan ninf contract float [[CONV_I]], [[Y]]
 // FINITEONLY-NEXT:    [[MUL8_I:%.*]] = fmul nnan ninf contract float [[__X1_0_I3]], [[DIV_I]]
 // FINITEONLY-NEXT:    [[SUB_I]] = fsub nnan ninf contract float [[MUL8_I]], [[__X0_0_I2]]
@@ -4288,7 +4288,7 @@ extern "C" __device__ double test_y1(double x) {
 // APPROX-NEXT:    [[__X1_0_I3:%.*]] = phi float [ [[SUB_I:%.*]], [[FOR_BODY_I]] ], [ [[CALL_I21_I]], [[IF_END4_I]] ]
 // APPROX-NEXT:    [[__X0_0_I2:%.*]] = phi float [ [[__X1_0_I3]], [[FOR_BODY_I]] ], [ [[CALL_I_I]], [[IF_END4_I]] ]
 // APPROX-NEXT:    [[MUL_I:%.*]] = shl nuw nsw i32 [[__I_0_I4]], 1
-// APPROX-NEXT:    [[CONV_I:%.*]] = sitofp i32 [[MUL_I]] to float
+// APPROX-NEXT:    [[CONV_I:%.*]] = uitofp nneg i32 [[MUL_I]] to float
 // APPROX-NEXT:    [[DIV_I:%.*]] = fdiv contract float [[CONV_I]], [[Y]]
 // APPROX-NEXT:    [[MUL8_I:%.*]] = fmul contract float [[__X1_0_I3]], [[DIV_I]]
 // APPROX-NEXT:    [[SUB_I]] = fsub contract float [[MUL8_I]], [[__X0_0_I2]]
@@ -4325,7 +4325,7 @@ extern "C" __device__ float test_ynf(int x, float y) {
 // DEFAULT-NEXT:    [[__X1_0_I3:%.*]] = phi double [ [[SUB_I:%.*]], [[FOR_BODY_I]] ], [ [[CALL_I21_I]], [[IF_END4_I]] ]
 // DEFAULT-NEXT:    [[__X0_0_I2:%.*]] = phi double [ [[__X1_0_I3]], [[FOR_BODY_I]] ], [ [[CALL_I_I]], [[IF_END4_I]] ]
 // DEFAULT-NEXT:    [[MUL_I:%.*]] = shl nuw nsw i32 [[__I_0_I4]], 1
-// DEFAULT-NEXT:    [[CONV_I:%.*]] = sitofp i32 [[MUL_I]] to double
+// DEFAULT-NEXT:    [[CONV_I:%.*]] = uitofp nneg i32 [[MUL_I]] to double
 // DEFAULT-NEXT:    [[DIV_I:%.*]] = fdiv contract double [[CONV_I]], [[Y]]
 // DEFAULT-NEXT:    [[MUL8_I:%.*]] = fmul contract double [[__X1_0_I3]], [[DIV_I]]
 // DEFAULT-NEXT:    [[SUB_I]] = fsub contract double [[MUL8_I]], [[__X0_0_I2]]
@@ -4358,7 +4358,7 @@ extern "C" __device__ float test_ynf(int x, float y) {
 // FINITEONLY-NEXT:    [[__X1_0_I3:%.*]] = phi double [ [[SUB_I:%.*]], [[FOR_BODY_I]] ], [ [[CALL_I21_I]], [[IF_END4_I]] ]
 // FINITEONLY-NEXT:    [[__X0_0_I2:%.*]] = phi double [ [[__X1_0_I3]], [[FOR_BODY_I]] ], [ [[CALL_I_I]], [[IF_END4_I]] ]
 // FINITEONLY-NEXT:    [[MUL_I:%.*]] = shl nuw nsw i32 [[__I_0_I4]], 1
-// FINITEONLY-NEXT:    [[CONV_I:%.*]] = sitofp i32 [[MUL_I]] to double
+// FINITEONLY-NEXT:    [[CONV_I:%.*]] = uitofp nneg i32 [[MUL_I]] to double
 // FINITEONLY-NEXT:    [[DIV_I:%.*]] = fdiv nnan ninf contract double [[CONV_I]], [[Y]]
 // FINITEONLY-NEXT:    [[MUL8_I:%.*]] = fmul nnan ninf contract double [[__X1_0_I3]], [[DIV_I]]
 // FINITEONLY-NEXT:    [[SUB_I]] = fsub nnan ninf contract double [[MUL8_I]], [[__X0_0_I2]]
@@ -4391,7 +4391,7 @@ extern "C" __device__ float test_ynf(int x, float y) {
 // APPROX-NEXT:    [[__X1_0_I3:%.*]] = phi double [ [[SUB_I:%.*]], [[FOR_BODY_I]] ], [ [[CALL_I21_I]], [[IF_END4_I]] ]
 // APPROX-NEXT:    [[__X0_0_I2:%.*]] = phi double [ [[__X1_0_I3]], [[FOR_BODY_I]] ], [ [[CALL_I_I]], [[IF_END4_I]] ]
 // APPROX-NEXT:    [[MUL_I:%.*]] = shl nuw nsw i32 [[__I_0_I4]], 1
-// APPROX-NEXT:    [[CONV_I:%.*]] = sitofp i32 [[MUL_I]] to double
+// APPROX-NEXT:    [[CONV_I:%.*]] = uitofp nneg i32 [[MUL_I]] to double
 // APPROX-NEXT:    [[DIV_I:%.*]] = fdiv contract double [[CONV_I]], [[Y]]
 // APPROX-NEXT:    [[MUL8_I:%.*]] = fmul contract double [[__X1_0_I3]], [[DIV_I]]
 // APPROX-NEXT:    [[SUB_I]] = fsub contract double [[MUL8_I]], [[__X0_0_I2]]
diff --git a/llvm/lib/Transforms/InstCombine/InstCombineCasts.cpp b/llvm/lib/Transforms/InstCombine/InstCombineCasts.cpp
index 0652a8ba80b3fe..0a95a9224db025 100644
--- a/llvm/lib/Transforms/InstCombine/InstCombineCasts.cpp
+++ b/llvm/lib/Transforms/InstCombine/InstCombineCasts.cpp
@@ -1964,11 +1964,25 @@ Instruction *InstCombinerImpl::visitFPToSI(FPToSIInst &FI) {
 }
 
 Instruction *InstCombinerImpl::visitUIToFP(CastInst &CI) {
-  return commonCastTransforms(CI);
+  if (Instruction *R = commonCastTransforms(CI))
+    return R;
+  if (!CI.hasNonNeg() && isKnownNonNegative(CI.getOperand(0), SQ)) {
+    CI.setNonNeg();
+    return &CI;
+  }
+  return nullptr;
 }
 
 Instruction *InstCombinerImpl::visitSIToFP(CastInst &CI) {
-  return commonCastTransforms(CI);
+  if (Instruction *R = commonCastTransforms(CI))
+    return R;
+  if (isKnownNonNegative(CI.getOperand(0), SQ)) {
+    auto UI =
+        CastInst::Create(Instruction::UIToFP, CI.getOperand(0), CI.getType());
+    UI->setNonNeg(true);
+    return UI;
+  }
+  return nullptr;
 }
 
 Instruction *InstCombinerImpl::visitIntToPtr(IntToPtrInst &CI) {
diff --git a/llvm/test/Transforms/InstCombine/add-sitofp.ll b/llvm/test/Transforms/InstCombine/add-sitofp.ll
index 2bdc808d9771c4..f1afcaf5f85d2a 100644
--- a/llvm/test/Transforms/InstCombine/add-sitofp.ll
+++ b/llvm/test/Transforms/InstCombine/add-sitofp.ll
@@ -6,7 +6,7 @@ define double @x(i32 %a, i32 %b) {
 ; CHECK-NEXT:    [[M:%.*]] = lshr i32 [[A:%.*]], 24
 ; CHECK-NEXT:    [[N:%.*]] = and i32 [[M]], [[B:%.*]]
 ; CHECK-NEXT:    [[TMP1:%.*]] = add nuw nsw i32 [[N]], 1
-; CHECK-NEXT:    [[P:%.*]] = uitofp i32 [[TMP1]] to double
+; CHECK-NEXT:    [[P:%.*]] = uitofp nneg i32 [[TMP1]] to double
 ; CHECK-NEXT:    ret double [[P]]
 ;
   %m = lshr i32 %a, 24
@@ -20,7 +20,7 @@ define double @test(i32 %a) {
 ; CHECK-LABEL: @test(
 ; CHECK-NEXT:    [[A_AND:%.*]] = and i32 [[A:%.*]], 1073741823
 ; CHECK-NEXT:    [[TMP1:%.*]] = add nuw nsw i32 [[A_AND]], 1
-; CHECK-NEXT:    [[RES:%.*]] = uitofp i32 [[TMP1]] to double
+; CHECK-NEXT:    [[RES:%.*]] = uitofp nneg i32 [[TMP1]] to double
 ; CHECK-NEXT:    ret double [[RES]]
 ;
   ; Drop two highest bits to guarantee that %a + 1 doesn't overflow
@@ -33,7 +33,7 @@ define double @test(i32 %a) {
 define float @test_neg(i32 %a) {
 ; CHECK-LABEL: @test_neg(
 ; CHECK-NEXT:    [[A_AND:%.*]] = and i32 [[A:%.*]], 1073741823
-; CHECK-NEXT:    [[A_AND_FP:%.*]] = sitofp i32 [[A_AND]] to float
+; CHECK-NEXT:    [[A_AND_FP:%.*]] = uitofp nneg i32 [[A_AND]] to float
 ; CHECK-NEXT:    [[RES:%.*]] = fadd float [[A_AND_FP]], 1.000000e+00
 ; CHECK-NEXT:    ret float [[RES]]
 ;
@@ -49,7 +49,7 @@ define double @test_2(i32 %a, i32 %b) {
 ; CHECK-NEXT:    [[A_AND:%.*]] = and i32 [[A:%.*]], 1073741823
 ; CHECK-NEXT:    [[B_AND:%.*]] = and i32 [[B:%.*]], 1073741823
 ; CHECK-NEXT:    [[TMP1:%.*]] = add nuw nsw i32 [[A_AND]], [[B_AND]]
-; CHECK-NEXT:    [[RES:%.*]] = uitofp i32 [[TMP1]] to double
+; CHECK-NEXT:    [[RES:%.*]] = uitofp nneg i32 [[TMP1]] to double
 ; CHECK-NEXT:    ret double [[RES]]
 ;
   ; Drop two highest bits to guarantee that %a + %b doesn't overflow
@@ -67,8 +67,8 @@ define float @test_2_neg(i32 %a, i32 %b) {
 ; CHECK-LABEL: @test_2_neg(
 ; CHECK-NEXT:    [[A_AND:%.*]] = and i32 [[A:%.*]], 1073741823
 ; CHECK-NEXT:    [[B_AND:%.*]] = and i32 [[B:%.*]], 1073741823
-; CHECK-NEXT:    [[A_AND_FP:%.*]] = sitofp i32 [[A_AND]] to float
-; CHECK-NEXT:    [[B_AND_FP:%.*]] = sitofp i32 [[B_AND]] to float
+; CHECK-NEXT:    [[A_AND_FP:%.*]] = uitofp nneg i32 [[A_AND]] to float
+; CHECK-NEXT:    [[B_AND_FP:%.*]] = uitofp nneg i32 [[B_AND]] to float
 ; CHECK-NEXT:    [[RES:%.*]] = fadd float [[A_AND_FP]], [[B_AND_FP]]
 ; CHECK-NEXT:    ret float [[RES]]
 ;
@@ -89,7 +89,7 @@ define float @test_3(i32 %a, i32 %b) {
 ; CHECK-NEXT:    [[M:%.*]] = lshr i32 [[A:%.*]], 24
 ; CHECK-NEXT:    [[N:%.*]] = and i32 [[M]], [[B:%.*]]
 ; CHECK-NEXT:    [[TMP1:%.*]] = add nuw nsw i32 [[N]], 1
-; CHECK-NEXT:    [[P:%.*]] = uitofp i32 [[TMP1]] to float
+; CHECK-NEXT:    [[P:%.*]] = uitofp nneg i32 [[TMP1]] to float
 ; CHECK-NEXT:    ret float [[P]]
 ;
   %m = lshr i32 %a, 24
@@ -104,7 +104,7 @@ define <4 x double> @test_4(<4 x i32> %a, <4 x i32> %b) {
 ; CHECK-NEXT:    [[A_AND:%.*]] = and <4 x i32> [[A:%.*]], <i32 1073741823, i32 1073741823, i32 1073741823, i32 1073741823>
 ; CHECK-NEXT:    [[B_AND:%.*]] = and <4 x i32> [[B:%.*]], <i32 1073741823, i32 1073741823, i32 1073741823, i32 1073741823>
 ; CHECK-NEXT:    [[TMP1:%.*]] = add nuw nsw <4 x i32> [[A_AND]], [[B_AND]]
-; CHECK-NEXT:    [[RES:%.*]] = uitofp <4 x i32> [[TMP1]] to <4 x double>
+; CHECK-NEXT:    [[RES:%.*]] = uitofp nneg <4 x i32> [[TMP1]] to <4 x double>
 ; CHECK-NEXT:    ret <4 x double> [[RES]]
 ;
   ; Drop two highest bits to guarantee that %a + %b doesn't overflow
@@ -122,8 +122,8 @@ define <4 x float> @test_4_neg(<4 x i32> %a, <4 x i32> %b) {
 ; CHECK-LABEL: @test_4_neg(
 ; CHECK-NEXT:    [[A_AND:%.*]] = and <4 x i32> [[A:%.*]], <i32 1073741823, i32 1073741823, i32 1073741823, i32 1073741823>
 ; CHECK-NEXT:    [[B_AND:%.*]] = and <4 x i32> [[B:%.*]], <i32 1073741823, i32 1073741823, i32 1073741823, i32 1073741823>
-; CHECK-NEXT:    [[A_AND_FP:%.*]] = sitofp <4 x i32> [[A_AND]] to <4 x float>
-; CHECK-NEXT:    [[B_AND_FP:%.*]] = sitofp <4 x i32> [[B_AND]] to <4 x float>
+; CHECK-NEXT:    [[A_AND_FP:%.*]] = uitofp nneg <4 x i32> [[A_AND]] to <4 x float>
+; CHECK-NEXT:    [[B_AND_FP:%.*]] = uitofp nneg <4 x i32> [[B_AND]] to <4 x float>
 ; CHECK-NEXT:    [[RES:%.*]] = fadd <4 x float> [[A_AND_FP]], [[B_AND_FP]]
 ; CHECK-NEXT:    ret <4 x float> [[RES]]
 ;
diff --git a/llvm/test/Transforms/InstCombine/binop-itofp.ll b/llvm/test/Transforms/InstCombine/binop-itofp.ll
index cd9ec1e59203ff..4f87b892e32a13 100644
--- a/llvm/test/Transforms/InstCombine/binop-itofp.ll
+++ b/llvm/test/Transforms/InstCombine/binop-itofp.ll
@@ -21,7 +21,7 @@ define half @test_ui_ui_i8_add_fail_overflow(i8 noundef %x_in, i8 noundef %y_in)
 ; CHECK-LABEL: @test_ui_ui_i8_add_fail_overflow(
 ; CHECK-NEXT:    [[X:%.*]] = and i8 [[X_IN:%.*]], 127
 ; CHECK-NEXT:    [[Y:%.*]] = and i8 [[Y_IN:%.*]], -127
-; CHECK-NEXT:    [[XF:%.*]] = uitofp i8 [[X]] to half
+; CHECK-NEXT:    [[XF:%.*]] = uitofp nneg i8 [[X]] to half
 ; CHECK-NEXT:    [[YF:%.*]] = uitofp i8 [[Y]] to half
 ; CHECK-NEXT:    [[R:%.*]] = fadd half [[XF]], [[YF]]
 ; CHECK-NEXT:    ret half [[R]]
@@ -49,7 +49,7 @@ define half @test_ui_ui_i8_add_C(i8 noundef %x_in) {
 define half @test_ui_ui_i8_add_C_fail_no_repr(i8 noundef %x_in) {
 ; CHECK-LABEL: @test_ui_ui_i8_add_C_fail_no_repr(
 ; CHECK-NEXT:    [[X:%.*]] = and i8 [[X_IN:%.*]], 127
-; CHECK-NEXT:    [[XF:%.*]] = uitofp i8 [[X]] to half
+; CHECK-NEXT:    [[XF:%.*]] = uitofp nneg i8 [[X]] to half
 ; CHECK-NEXT:    [[R:%.*]] = fadd half [[XF]], 0xH57F8
 ; CHECK-NEXT:    ret half [[R]]
 ;
@@ -62,7 +62,7 @@ define half @test_ui_ui_i8_add_C_fail_no_repr(i8 noundef %x_in) {
 define half @test_ui_ui_i8_add_C_fail_overflow(i8 noundef %x_in) {
 ; CHECK-LABEL: @test_ui_ui_i8_add_C_fail_overflow(
 ; CHECK-NEXT:    [[X:%.*]] = and i8 [[X_IN:%.*]], 127
-; CHECK-NEXT:    [[XF:%.*]] = uitofp i8 [[X]] to half
+; CHECK-NEXT:    [[XF:%.*]] = uitofp nneg i8 [[X]] to half
 ; CHECK-NEXT:    [[R:%.*]] = fadd half [[XF]], 0xH5808
 ; CHECK-NEXT:    ret half [[R]]
 ;
@@ -110,7 +110,7 @@ define half @test_ui_si_i8_add(i8 noundef %x_in, i8 noundef %y_in) {
 ; CHECK-NEXT:    [[X:%.*]] = and i8 [[X_IN:%.*]], 63
 ; CHECK-NEXT:    [[Y:%.*]] = and i8 [[Y_IN:%.*]], 63
 ; CHECK-NEXT:    [[TMP1:%.*]] = add nuw nsw i8 [[X]], [[Y]]
-; CHECK-NEXT:    [[R:%.*]] = uitofp i8 [[TMP1]] to half
+; CHECK-NEXT:    [[R:%.*]] = uitofp nneg i8 [[TMP1]] to half
 ; CHECK-NEXT:    ret half [[R]]
 ;
   %x = and i8 %x_in, 63
@@ -140,7 +140,7 @@ define half @test_ui_si_i8_add_overflow(i8 noundef %x_in, i8 noundef %y_in) {
 define half @test_ui_ui_i8_sub_C(i8 noundef %x_in) {
 ; CHECK-LABEL: @test_ui_ui_i8_sub_C(
 ; CHECK-NEXT:    [[TMP1:%.*]] = and i8 [[X_IN:%.*]], 127
-; CHECK-NEXT:    [[R:%.*]] = uitofp i8 [[TMP1]] to half
+; CHECK-NEXT:    [[R:%.*]] = uitofp nneg i8 [[TMP1]] to half
 ; CHECK-NEXT:    ret half [[R]]
 ;
   %x = or i8 %x_in, 128
@@ -166,7 +166,7 @@ define half @test_si_si_i8_sub(i8 noundef %x_in, i8 noundef %y_in) {
 ; CHECK-NEXT:    [[X:%.*]] = and i8 [[X_IN:%.*]], 63
 ; CHECK-NEXT:    [[Y:%.*]] = or i8 [[Y_IN:%.*]], -64
 ; CHECK-NEXT:    [[TMP1:%.*]] = sub nsw i8 [[X]], [[Y]]
-; CHECK-NEXT:    [[R:%.*]] = sitofp i8 [[TMP1]] to half
+; CHECK-NEXT:    [[R:%.*]] = uitofp nneg i8 [[TMP1]] to half
 ; CHECK-NEXT:    ret half [[R]]
 ;
   %x = and i8 %x_in, 63
@@ -181,7 +181,7 @@ define half @test_si_si_i8_sub_fail_overflow(i8 noundef %x_in, i8 noundef %y_in)
 ; CHECK-LABEL: @test_si_si_i8_sub_fail_overflow(
 ; CHECK-NEXT:    [[X:%.*]] = and i8 [[X_IN:%.*]], 63
 ; CHECK-NEXT:    [[Y:%.*]] = or i8 [[Y_IN:%.*]], -65
-; CHECK-NEXT:    [[XF:%.*]] = sitofp i8 [[X]] to half
+; CHECK-NEXT:    [[XF:%.*]] = uitofp nneg i8 [[X]] to half
 ; CHECK-NEXT:    [[YF:%.*]] = sitofp i8 [[Y]] to half
 ; CHECK-NEXT:    [[R:%.*]] = fsub half [[XF]], [[YF]]
 ; CHECK-NEXT:    ret half [[R]]
@@ -198,7 +198,7 @@ define half @test_si_si_i8_sub_C(i8 noundef %x_in) {
 ; CHECK-LABEL: @test_si_si_i8_sub_C(
 ; CHECK-NEXT:    [[X:%.*]] = and i8 [[X_IN:%.*]], 63
 ; CHECK-NEXT:    [[TMP1:%.*]] = or disjoint i8 [[X]], 64
-; CHECK-NEXT:    [[R:%.*]] = sitofp i8 [[TMP1]] to half
+; CHECK-NEXT:    [[R:%.*]] = uitofp nneg i8 [[TMP1]] to half
 ; CHECK-NEXT:    ret half [[R]]
 ;
   %x = and i8 %x_in, 63
@@ -283,7 +283,7 @@ define half @test_ui_ui_i8_mul_C(i8 noundef %x_in) {
 define half @test_ui_ui_i8_mul_C_fail_overlow(i8 noundef %x_in) {
 ; CHECK-LABEL: @test_ui_ui_i8_mul_C_fail_overlow(
 ; CHECK-NEXT:    [[X:%.*]] = and i8 [[X_IN:%.*]], 14
-; CHECK-NEXT:    [[XF:%.*]] = uitofp i8 [[X]] to half
+; CHECK-NEXT:    [[XF:%.*]] = uitofp nneg i8 [[X]] to half
 ; CHECK-NEXT:    [[R:%.*]] = fmul half [[XF]], 0xH4CC0
 ; CHECK-NEXT:    ret half [[R]]
 ;
@@ -315,7 +315,7 @@ define half @test_si_si_i8_mul_fail_maybe_zero(i8 noundef %x_in, i8 noundef %y_i
 ; CHECK-LABEL: @test_si_si_i8_mul_fail_maybe_zero(
 ; CHECK-NEXT:    [[X:%.*]] = and i8 [[X_IN:%.*]], 7
 ; CHECK-NEXT:    [[Y:%.*]] = or i8 [[Y_IN:%.*]], -8
-; CHECK-NEXT:    [[XF:%.*]] = sitofp i8 [[X]] to half
+; CHECK-NEXT:    [[XF:%.*]] = uitofp nneg i8 [[X]] to half
 ; CHECK-NEXT:    [[YF:%.*]] = sitofp i8 [[Y]] to half
 ; CHECK-NEXT:    [[R:%.*]] = fmul half [[XF]], [[YF]]
 ; CHECK-NEXT:    ret half [[R]]
@@ -332,7 +332,7 @@ define half @test_si_si_i8_mul_C_fail_no_repr(i8 noundef %x_in) {
 ; CHECK-LABEL: @test_si_si_i8_mul_C_fail_no_repr(
 ; CHECK-NEXT:    [[XX:%.*]] = and i8 [[X_IN:%.*]], 6
 ; CHECK-NEXT:    [[X:%.*]] = or disjoint i8 [[XX]], 1
-; CHECK-NEXT:    [[XF:%.*]] = sitofp i8 [[X]] to half
+; CHECK-NEXT:    [[XF:%.*]] = uitofp nneg i8 [[X]] to half
 ; CHECK-NEXT:    [[R:%.*]] = fmul half [[XF]], 0x...
[truncated]

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llvmbot commented Apr 10, 2024

@llvm/pr-subscribers-llvm-transforms

Author: None (goldsteinn)

Changes

This is essentially the same as #82404 but has the nneg flag which
allows the backend to reliably undo the transform.

Patch is 61.71 KiB, truncated to 20.00 KiB below, full version: https://github.com/llvm/llvm-project/pull/88299.diff

12 Files Affected:

  • (modified) clang/test/Headers/__clang_hip_math.hip (+12-12)
  • (modified) llvm/lib/Transforms/InstCombine/InstCombineCasts.cpp (+16-2)
  • (modified) llvm/test/Transforms/InstCombine/add-sitofp.ll (+10-10)
  • (modified) llvm/test/Transforms/InstCombine/binop-itofp.ll (+33-33)
  • (modified) llvm/test/Transforms/InstCombine/clamp-to-minmax.ll (+5-5)
  • (modified) llvm/test/Transforms/InstCombine/fpcast.ll (+12-12)
  • (modified) llvm/test/Transforms/InstCombine/minmax-fold.ll (+5-5)
  • (modified) llvm/test/Transforms/InstCombine/minmax-fp.ll (+1-1)
  • (modified) llvm/test/Transforms/InstCombine/pr27236.ll (+1-1)
  • (modified) llvm/test/Transforms/InstCombine/sitofp.ll (+1-1)
  • (modified) llvm/test/Transforms/LoopVectorize/X86/float-induction-x86.ll (+3-3)
  • (modified) llvm/test/Transforms/LoopVectorize/float-induction.ll (+28-28)
diff --git a/clang/test/Headers/__clang_hip_math.hip b/clang/test/Headers/__clang_hip_math.hip
index 37099de74fb8ec..bff1708120604b 100644
--- a/clang/test/Headers/__clang_hip_math.hip
+++ b/clang/test/Headers/__clang_hip_math.hip
@@ -1685,7 +1685,7 @@ extern "C" __device__ double test_j1(double x) {
 // DEFAULT-NEXT:    [[__X1_0_I3:%.*]] = phi float [ [[SUB_I:%.*]], [[FOR_BODY_I]] ], [ [[CALL_I21_I]], [[IF_END4_I]] ]
 // DEFAULT-NEXT:    [[__X0_0_I2:%.*]] = phi float [ [[__X1_0_I3]], [[FOR_BODY_I]] ], [ [[CALL_I_I]], [[IF_END4_I]] ]
 // DEFAULT-NEXT:    [[MUL_I:%.*]] = shl nuw nsw i32 [[__I_0_I4]], 1
-// DEFAULT-NEXT:    [[CONV_I:%.*]] = sitofp i32 [[MUL_I]] to float
+// DEFAULT-NEXT:    [[CONV_I:%.*]] = uitofp nneg i32 [[MUL_I]] to float
 // DEFAULT-NEXT:    [[DIV_I:%.*]] = fdiv contract float [[CONV_I]], [[Y]]
 // DEFAULT-NEXT:    [[MUL8_I:%.*]] = fmul contract float [[__X1_0_I3]], [[DIV_I]]
 // DEFAULT-NEXT:    [[SUB_I]] = fsub contract float [[MUL8_I]], [[__X0_0_I2]]
@@ -1718,7 +1718,7 @@ extern "C" __device__ double test_j1(double x) {
 // FINITEONLY-NEXT:    [[__X1_0_I3:%.*]] = phi float [ [[SUB_I:%.*]], [[FOR_BODY_I]] ], [ [[CALL_I21_I]], [[IF_END4_I]] ]
 // FINITEONLY-NEXT:    [[__X0_0_I2:%.*]] = phi float [ [[__X1_0_I3]], [[FOR_BODY_I]] ], [ [[CALL_I_I]], [[IF_END4_I]] ]
 // FINITEONLY-NEXT:    [[MUL_I:%.*]] = shl nuw nsw i32 [[__I_0_I4]], 1
-// FINITEONLY-NEXT:    [[CONV_I:%.*]] = sitofp i32 [[MUL_I]] to float
+// FINITEONLY-NEXT:    [[CONV_I:%.*]] = uitofp nneg i32 [[MUL_I]] to float
 // FINITEONLY-NEXT:    [[DIV_I:%.*]] = fdiv nnan ninf contract float [[CONV_I]], [[Y]]
 // FINITEONLY-NEXT:    [[MUL8_I:%.*]] = fmul nnan ninf contract float [[__X1_0_I3]], [[DIV_I]]
 // FINITEONLY-NEXT:    [[SUB_I]] = fsub nnan ninf contract float [[MUL8_I]], [[__X0_0_I2]]
@@ -1751,7 +1751,7 @@ extern "C" __device__ double test_j1(double x) {
 // APPROX-NEXT:    [[__X1_0_I3:%.*]] = phi float [ [[SUB_I:%.*]], [[FOR_BODY_I]] ], [ [[CALL_I21_I]], [[IF_END4_I]] ]
 // APPROX-NEXT:    [[__X0_0_I2:%.*]] = phi float [ [[__X1_0_I3]], [[FOR_BODY_I]] ], [ [[CALL_I_I]], [[IF_END4_I]] ]
 // APPROX-NEXT:    [[MUL_I:%.*]] = shl nuw nsw i32 [[__I_0_I4]], 1
-// APPROX-NEXT:    [[CONV_I:%.*]] = sitofp i32 [[MUL_I]] to float
+// APPROX-NEXT:    [[CONV_I:%.*]] = uitofp nneg i32 [[MUL_I]] to float
 // APPROX-NEXT:    [[DIV_I:%.*]] = fdiv contract float [[CONV_I]], [[Y]]
 // APPROX-NEXT:    [[MUL8_I:%.*]] = fmul contract float [[__X1_0_I3]], [[DIV_I]]
 // APPROX-NEXT:    [[SUB_I]] = fsub contract float [[MUL8_I]], [[__X0_0_I2]]
@@ -1788,7 +1788,7 @@ extern "C" __device__ float test_jnf(int x, float y) {
 // DEFAULT-NEXT:    [[__X1_0_I3:%.*]] = phi double [ [[SUB_I:%.*]], [[FOR_BODY_I]] ], [ [[CALL_I21_I]], [[IF_END4_I]] ]
 // DEFAULT-NEXT:    [[__X0_0_I2:%.*]] = phi double [ [[__X1_0_I3]], [[FOR_BODY_I]] ], [ [[CALL_I_I]], [[IF_END4_I]] ]
 // DEFAULT-NEXT:    [[MUL_I:%.*]] = shl nuw nsw i32 [[__I_0_I4]], 1
-// DEFAULT-NEXT:    [[CONV_I:%.*]] = sitofp i32 [[MUL_I]] to double
+// DEFAULT-NEXT:    [[CONV_I:%.*]] = uitofp nneg i32 [[MUL_I]] to double
 // DEFAULT-NEXT:    [[DIV_I:%.*]] = fdiv contract double [[CONV_I]], [[Y]]
 // DEFAULT-NEXT:    [[MUL8_I:%.*]] = fmul contract double [[__X1_0_I3]], [[DIV_I]]
 // DEFAULT-NEXT:    [[SUB_I]] = fsub contract double [[MUL8_I]], [[__X0_0_I2]]
@@ -1821,7 +1821,7 @@ extern "C" __device__ float test_jnf(int x, float y) {
 // FINITEONLY-NEXT:    [[__X1_0_I3:%.*]] = phi double [ [[SUB_I:%.*]], [[FOR_BODY_I]] ], [ [[CALL_I21_I]], [[IF_END4_I]] ]
 // FINITEONLY-NEXT:    [[__X0_0_I2:%.*]] = phi double [ [[__X1_0_I3]], [[FOR_BODY_I]] ], [ [[CALL_I_I]], [[IF_END4_I]] ]
 // FINITEONLY-NEXT:    [[MUL_I:%.*]] = shl nuw nsw i32 [[__I_0_I4]], 1
-// FINITEONLY-NEXT:    [[CONV_I:%.*]] = sitofp i32 [[MUL_I]] to double
+// FINITEONLY-NEXT:    [[CONV_I:%.*]] = uitofp nneg i32 [[MUL_I]] to double
 // FINITEONLY-NEXT:    [[DIV_I:%.*]] = fdiv nnan ninf contract double [[CONV_I]], [[Y]]
 // FINITEONLY-NEXT:    [[MUL8_I:%.*]] = fmul nnan ninf contract double [[__X1_0_I3]], [[DIV_I]]
 // FINITEONLY-NEXT:    [[SUB_I]] = fsub nnan ninf contract double [[MUL8_I]], [[__X0_0_I2]]
@@ -1854,7 +1854,7 @@ extern "C" __device__ float test_jnf(int x, float y) {
 // APPROX-NEXT:    [[__X1_0_I3:%.*]] = phi double [ [[SUB_I:%.*]], [[FOR_BODY_I]] ], [ [[CALL_I21_I]], [[IF_END4_I]] ]
 // APPROX-NEXT:    [[__X0_0_I2:%.*]] = phi double [ [[__X1_0_I3]], [[FOR_BODY_I]] ], [ [[CALL_I_I]], [[IF_END4_I]] ]
 // APPROX-NEXT:    [[MUL_I:%.*]] = shl nuw nsw i32 [[__I_0_I4]], 1
-// APPROX-NEXT:    [[CONV_I:%.*]] = sitofp i32 [[MUL_I]] to double
+// APPROX-NEXT:    [[CONV_I:%.*]] = uitofp nneg i32 [[MUL_I]] to double
 // APPROX-NEXT:    [[DIV_I:%.*]] = fdiv contract double [[CONV_I]], [[Y]]
 // APPROX-NEXT:    [[MUL8_I:%.*]] = fmul contract double [[__X1_0_I3]], [[DIV_I]]
 // APPROX-NEXT:    [[SUB_I]] = fsub contract double [[MUL8_I]], [[__X0_0_I2]]
@@ -4222,7 +4222,7 @@ extern "C" __device__ double test_y1(double x) {
 // DEFAULT-NEXT:    [[__X1_0_I3:%.*]] = phi float [ [[SUB_I:%.*]], [[FOR_BODY_I]] ], [ [[CALL_I21_I]], [[IF_END4_I]] ]
 // DEFAULT-NEXT:    [[__X0_0_I2:%.*]] = phi float [ [[__X1_0_I3]], [[FOR_BODY_I]] ], [ [[CALL_I_I]], [[IF_END4_I]] ]
 // DEFAULT-NEXT:    [[MUL_I:%.*]] = shl nuw nsw i32 [[__I_0_I4]], 1
-// DEFAULT-NEXT:    [[CONV_I:%.*]] = sitofp i32 [[MUL_I]] to float
+// DEFAULT-NEXT:    [[CONV_I:%.*]] = uitofp nneg i32 [[MUL_I]] to float
 // DEFAULT-NEXT:    [[DIV_I:%.*]] = fdiv contract float [[CONV_I]], [[Y]]
 // DEFAULT-NEXT:    [[MUL8_I:%.*]] = fmul contract float [[__X1_0_I3]], [[DIV_I]]
 // DEFAULT-NEXT:    [[SUB_I]] = fsub contract float [[MUL8_I]], [[__X0_0_I2]]
@@ -4255,7 +4255,7 @@ extern "C" __device__ double test_y1(double x) {
 // FINITEONLY-NEXT:    [[__X1_0_I3:%.*]] = phi float [ [[SUB_I:%.*]], [[FOR_BODY_I]] ], [ [[CALL_I21_I]], [[IF_END4_I]] ]
 // FINITEONLY-NEXT:    [[__X0_0_I2:%.*]] = phi float [ [[__X1_0_I3]], [[FOR_BODY_I]] ], [ [[CALL_I_I]], [[IF_END4_I]] ]
 // FINITEONLY-NEXT:    [[MUL_I:%.*]] = shl nuw nsw i32 [[__I_0_I4]], 1
-// FINITEONLY-NEXT:    [[CONV_I:%.*]] = sitofp i32 [[MUL_I]] to float
+// FINITEONLY-NEXT:    [[CONV_I:%.*]] = uitofp nneg i32 [[MUL_I]] to float
 // FINITEONLY-NEXT:    [[DIV_I:%.*]] = fdiv nnan ninf contract float [[CONV_I]], [[Y]]
 // FINITEONLY-NEXT:    [[MUL8_I:%.*]] = fmul nnan ninf contract float [[__X1_0_I3]], [[DIV_I]]
 // FINITEONLY-NEXT:    [[SUB_I]] = fsub nnan ninf contract float [[MUL8_I]], [[__X0_0_I2]]
@@ -4288,7 +4288,7 @@ extern "C" __device__ double test_y1(double x) {
 // APPROX-NEXT:    [[__X1_0_I3:%.*]] = phi float [ [[SUB_I:%.*]], [[FOR_BODY_I]] ], [ [[CALL_I21_I]], [[IF_END4_I]] ]
 // APPROX-NEXT:    [[__X0_0_I2:%.*]] = phi float [ [[__X1_0_I3]], [[FOR_BODY_I]] ], [ [[CALL_I_I]], [[IF_END4_I]] ]
 // APPROX-NEXT:    [[MUL_I:%.*]] = shl nuw nsw i32 [[__I_0_I4]], 1
-// APPROX-NEXT:    [[CONV_I:%.*]] = sitofp i32 [[MUL_I]] to float
+// APPROX-NEXT:    [[CONV_I:%.*]] = uitofp nneg i32 [[MUL_I]] to float
 // APPROX-NEXT:    [[DIV_I:%.*]] = fdiv contract float [[CONV_I]], [[Y]]
 // APPROX-NEXT:    [[MUL8_I:%.*]] = fmul contract float [[__X1_0_I3]], [[DIV_I]]
 // APPROX-NEXT:    [[SUB_I]] = fsub contract float [[MUL8_I]], [[__X0_0_I2]]
@@ -4325,7 +4325,7 @@ extern "C" __device__ float test_ynf(int x, float y) {
 // DEFAULT-NEXT:    [[__X1_0_I3:%.*]] = phi double [ [[SUB_I:%.*]], [[FOR_BODY_I]] ], [ [[CALL_I21_I]], [[IF_END4_I]] ]
 // DEFAULT-NEXT:    [[__X0_0_I2:%.*]] = phi double [ [[__X1_0_I3]], [[FOR_BODY_I]] ], [ [[CALL_I_I]], [[IF_END4_I]] ]
 // DEFAULT-NEXT:    [[MUL_I:%.*]] = shl nuw nsw i32 [[__I_0_I4]], 1
-// DEFAULT-NEXT:    [[CONV_I:%.*]] = sitofp i32 [[MUL_I]] to double
+// DEFAULT-NEXT:    [[CONV_I:%.*]] = uitofp nneg i32 [[MUL_I]] to double
 // DEFAULT-NEXT:    [[DIV_I:%.*]] = fdiv contract double [[CONV_I]], [[Y]]
 // DEFAULT-NEXT:    [[MUL8_I:%.*]] = fmul contract double [[__X1_0_I3]], [[DIV_I]]
 // DEFAULT-NEXT:    [[SUB_I]] = fsub contract double [[MUL8_I]], [[__X0_0_I2]]
@@ -4358,7 +4358,7 @@ extern "C" __device__ float test_ynf(int x, float y) {
 // FINITEONLY-NEXT:    [[__X1_0_I3:%.*]] = phi double [ [[SUB_I:%.*]], [[FOR_BODY_I]] ], [ [[CALL_I21_I]], [[IF_END4_I]] ]
 // FINITEONLY-NEXT:    [[__X0_0_I2:%.*]] = phi double [ [[__X1_0_I3]], [[FOR_BODY_I]] ], [ [[CALL_I_I]], [[IF_END4_I]] ]
 // FINITEONLY-NEXT:    [[MUL_I:%.*]] = shl nuw nsw i32 [[__I_0_I4]], 1
-// FINITEONLY-NEXT:    [[CONV_I:%.*]] = sitofp i32 [[MUL_I]] to double
+// FINITEONLY-NEXT:    [[CONV_I:%.*]] = uitofp nneg i32 [[MUL_I]] to double
 // FINITEONLY-NEXT:    [[DIV_I:%.*]] = fdiv nnan ninf contract double [[CONV_I]], [[Y]]
 // FINITEONLY-NEXT:    [[MUL8_I:%.*]] = fmul nnan ninf contract double [[__X1_0_I3]], [[DIV_I]]
 // FINITEONLY-NEXT:    [[SUB_I]] = fsub nnan ninf contract double [[MUL8_I]], [[__X0_0_I2]]
@@ -4391,7 +4391,7 @@ extern "C" __device__ float test_ynf(int x, float y) {
 // APPROX-NEXT:    [[__X1_0_I3:%.*]] = phi double [ [[SUB_I:%.*]], [[FOR_BODY_I]] ], [ [[CALL_I21_I]], [[IF_END4_I]] ]
 // APPROX-NEXT:    [[__X0_0_I2:%.*]] = phi double [ [[__X1_0_I3]], [[FOR_BODY_I]] ], [ [[CALL_I_I]], [[IF_END4_I]] ]
 // APPROX-NEXT:    [[MUL_I:%.*]] = shl nuw nsw i32 [[__I_0_I4]], 1
-// APPROX-NEXT:    [[CONV_I:%.*]] = sitofp i32 [[MUL_I]] to double
+// APPROX-NEXT:    [[CONV_I:%.*]] = uitofp nneg i32 [[MUL_I]] to double
 // APPROX-NEXT:    [[DIV_I:%.*]] = fdiv contract double [[CONV_I]], [[Y]]
 // APPROX-NEXT:    [[MUL8_I:%.*]] = fmul contract double [[__X1_0_I3]], [[DIV_I]]
 // APPROX-NEXT:    [[SUB_I]] = fsub contract double [[MUL8_I]], [[__X0_0_I2]]
diff --git a/llvm/lib/Transforms/InstCombine/InstCombineCasts.cpp b/llvm/lib/Transforms/InstCombine/InstCombineCasts.cpp
index 0652a8ba80b3fe..0a95a9224db025 100644
--- a/llvm/lib/Transforms/InstCombine/InstCombineCasts.cpp
+++ b/llvm/lib/Transforms/InstCombine/InstCombineCasts.cpp
@@ -1964,11 +1964,25 @@ Instruction *InstCombinerImpl::visitFPToSI(FPToSIInst &FI) {
 }
 
 Instruction *InstCombinerImpl::visitUIToFP(CastInst &CI) {
-  return commonCastTransforms(CI);
+  if (Instruction *R = commonCastTransforms(CI))
+    return R;
+  if (!CI.hasNonNeg() && isKnownNonNegative(CI.getOperand(0), SQ)) {
+    CI.setNonNeg();
+    return &CI;
+  }
+  return nullptr;
 }
 
 Instruction *InstCombinerImpl::visitSIToFP(CastInst &CI) {
-  return commonCastTransforms(CI);
+  if (Instruction *R = commonCastTransforms(CI))
+    return R;
+  if (isKnownNonNegative(CI.getOperand(0), SQ)) {
+    auto UI =
+        CastInst::Create(Instruction::UIToFP, CI.getOperand(0), CI.getType());
+    UI->setNonNeg(true);
+    return UI;
+  }
+  return nullptr;
 }
 
 Instruction *InstCombinerImpl::visitIntToPtr(IntToPtrInst &CI) {
diff --git a/llvm/test/Transforms/InstCombine/add-sitofp.ll b/llvm/test/Transforms/InstCombine/add-sitofp.ll
index 2bdc808d9771c4..f1afcaf5f85d2a 100644
--- a/llvm/test/Transforms/InstCombine/add-sitofp.ll
+++ b/llvm/test/Transforms/InstCombine/add-sitofp.ll
@@ -6,7 +6,7 @@ define double @x(i32 %a, i32 %b) {
 ; CHECK-NEXT:    [[M:%.*]] = lshr i32 [[A:%.*]], 24
 ; CHECK-NEXT:    [[N:%.*]] = and i32 [[M]], [[B:%.*]]
 ; CHECK-NEXT:    [[TMP1:%.*]] = add nuw nsw i32 [[N]], 1
-; CHECK-NEXT:    [[P:%.*]] = uitofp i32 [[TMP1]] to double
+; CHECK-NEXT:    [[P:%.*]] = uitofp nneg i32 [[TMP1]] to double
 ; CHECK-NEXT:    ret double [[P]]
 ;
   %m = lshr i32 %a, 24
@@ -20,7 +20,7 @@ define double @test(i32 %a) {
 ; CHECK-LABEL: @test(
 ; CHECK-NEXT:    [[A_AND:%.*]] = and i32 [[A:%.*]], 1073741823
 ; CHECK-NEXT:    [[TMP1:%.*]] = add nuw nsw i32 [[A_AND]], 1
-; CHECK-NEXT:    [[RES:%.*]] = uitofp i32 [[TMP1]] to double
+; CHECK-NEXT:    [[RES:%.*]] = uitofp nneg i32 [[TMP1]] to double
 ; CHECK-NEXT:    ret double [[RES]]
 ;
   ; Drop two highest bits to guarantee that %a + 1 doesn't overflow
@@ -33,7 +33,7 @@ define double @test(i32 %a) {
 define float @test_neg(i32 %a) {
 ; CHECK-LABEL: @test_neg(
 ; CHECK-NEXT:    [[A_AND:%.*]] = and i32 [[A:%.*]], 1073741823
-; CHECK-NEXT:    [[A_AND_FP:%.*]] = sitofp i32 [[A_AND]] to float
+; CHECK-NEXT:    [[A_AND_FP:%.*]] = uitofp nneg i32 [[A_AND]] to float
 ; CHECK-NEXT:    [[RES:%.*]] = fadd float [[A_AND_FP]], 1.000000e+00
 ; CHECK-NEXT:    ret float [[RES]]
 ;
@@ -49,7 +49,7 @@ define double @test_2(i32 %a, i32 %b) {
 ; CHECK-NEXT:    [[A_AND:%.*]] = and i32 [[A:%.*]], 1073741823
 ; CHECK-NEXT:    [[B_AND:%.*]] = and i32 [[B:%.*]], 1073741823
 ; CHECK-NEXT:    [[TMP1:%.*]] = add nuw nsw i32 [[A_AND]], [[B_AND]]
-; CHECK-NEXT:    [[RES:%.*]] = uitofp i32 [[TMP1]] to double
+; CHECK-NEXT:    [[RES:%.*]] = uitofp nneg i32 [[TMP1]] to double
 ; CHECK-NEXT:    ret double [[RES]]
 ;
   ; Drop two highest bits to guarantee that %a + %b doesn't overflow
@@ -67,8 +67,8 @@ define float @test_2_neg(i32 %a, i32 %b) {
 ; CHECK-LABEL: @test_2_neg(
 ; CHECK-NEXT:    [[A_AND:%.*]] = and i32 [[A:%.*]], 1073741823
 ; CHECK-NEXT:    [[B_AND:%.*]] = and i32 [[B:%.*]], 1073741823
-; CHECK-NEXT:    [[A_AND_FP:%.*]] = sitofp i32 [[A_AND]] to float
-; CHECK-NEXT:    [[B_AND_FP:%.*]] = sitofp i32 [[B_AND]] to float
+; CHECK-NEXT:    [[A_AND_FP:%.*]] = uitofp nneg i32 [[A_AND]] to float
+; CHECK-NEXT:    [[B_AND_FP:%.*]] = uitofp nneg i32 [[B_AND]] to float
 ; CHECK-NEXT:    [[RES:%.*]] = fadd float [[A_AND_FP]], [[B_AND_FP]]
 ; CHECK-NEXT:    ret float [[RES]]
 ;
@@ -89,7 +89,7 @@ define float @test_3(i32 %a, i32 %b) {
 ; CHECK-NEXT:    [[M:%.*]] = lshr i32 [[A:%.*]], 24
 ; CHECK-NEXT:    [[N:%.*]] = and i32 [[M]], [[B:%.*]]
 ; CHECK-NEXT:    [[TMP1:%.*]] = add nuw nsw i32 [[N]], 1
-; CHECK-NEXT:    [[P:%.*]] = uitofp i32 [[TMP1]] to float
+; CHECK-NEXT:    [[P:%.*]] = uitofp nneg i32 [[TMP1]] to float
 ; CHECK-NEXT:    ret float [[P]]
 ;
   %m = lshr i32 %a, 24
@@ -104,7 +104,7 @@ define <4 x double> @test_4(<4 x i32> %a, <4 x i32> %b) {
 ; CHECK-NEXT:    [[A_AND:%.*]] = and <4 x i32> [[A:%.*]], <i32 1073741823, i32 1073741823, i32 1073741823, i32 1073741823>
 ; CHECK-NEXT:    [[B_AND:%.*]] = and <4 x i32> [[B:%.*]], <i32 1073741823, i32 1073741823, i32 1073741823, i32 1073741823>
 ; CHECK-NEXT:    [[TMP1:%.*]] = add nuw nsw <4 x i32> [[A_AND]], [[B_AND]]
-; CHECK-NEXT:    [[RES:%.*]] = uitofp <4 x i32> [[TMP1]] to <4 x double>
+; CHECK-NEXT:    [[RES:%.*]] = uitofp nneg <4 x i32> [[TMP1]] to <4 x double>
 ; CHECK-NEXT:    ret <4 x double> [[RES]]
 ;
   ; Drop two highest bits to guarantee that %a + %b doesn't overflow
@@ -122,8 +122,8 @@ define <4 x float> @test_4_neg(<4 x i32> %a, <4 x i32> %b) {
 ; CHECK-LABEL: @test_4_neg(
 ; CHECK-NEXT:    [[A_AND:%.*]] = and <4 x i32> [[A:%.*]], <i32 1073741823, i32 1073741823, i32 1073741823, i32 1073741823>
 ; CHECK-NEXT:    [[B_AND:%.*]] = and <4 x i32> [[B:%.*]], <i32 1073741823, i32 1073741823, i32 1073741823, i32 1073741823>
-; CHECK-NEXT:    [[A_AND_FP:%.*]] = sitofp <4 x i32> [[A_AND]] to <4 x float>
-; CHECK-NEXT:    [[B_AND_FP:%.*]] = sitofp <4 x i32> [[B_AND]] to <4 x float>
+; CHECK-NEXT:    [[A_AND_FP:%.*]] = uitofp nneg <4 x i32> [[A_AND]] to <4 x float>
+; CHECK-NEXT:    [[B_AND_FP:%.*]] = uitofp nneg <4 x i32> [[B_AND]] to <4 x float>
 ; CHECK-NEXT:    [[RES:%.*]] = fadd <4 x float> [[A_AND_FP]], [[B_AND_FP]]
 ; CHECK-NEXT:    ret <4 x float> [[RES]]
 ;
diff --git a/llvm/test/Transforms/InstCombine/binop-itofp.ll b/llvm/test/Transforms/InstCombine/binop-itofp.ll
index cd9ec1e59203ff..4f87b892e32a13 100644
--- a/llvm/test/Transforms/InstCombine/binop-itofp.ll
+++ b/llvm/test/Transforms/InstCombine/binop-itofp.ll
@@ -21,7 +21,7 @@ define half @test_ui_ui_i8_add_fail_overflow(i8 noundef %x_in, i8 noundef %y_in)
 ; CHECK-LABEL: @test_ui_ui_i8_add_fail_overflow(
 ; CHECK-NEXT:    [[X:%.*]] = and i8 [[X_IN:%.*]], 127
 ; CHECK-NEXT:    [[Y:%.*]] = and i8 [[Y_IN:%.*]], -127
-; CHECK-NEXT:    [[XF:%.*]] = uitofp i8 [[X]] to half
+; CHECK-NEXT:    [[XF:%.*]] = uitofp nneg i8 [[X]] to half
 ; CHECK-NEXT:    [[YF:%.*]] = uitofp i8 [[Y]] to half
 ; CHECK-NEXT:    [[R:%.*]] = fadd half [[XF]], [[YF]]
 ; CHECK-NEXT:    ret half [[R]]
@@ -49,7 +49,7 @@ define half @test_ui_ui_i8_add_C(i8 noundef %x_in) {
 define half @test_ui_ui_i8_add_C_fail_no_repr(i8 noundef %x_in) {
 ; CHECK-LABEL: @test_ui_ui_i8_add_C_fail_no_repr(
 ; CHECK-NEXT:    [[X:%.*]] = and i8 [[X_IN:%.*]], 127
-; CHECK-NEXT:    [[XF:%.*]] = uitofp i8 [[X]] to half
+; CHECK-NEXT:    [[XF:%.*]] = uitofp nneg i8 [[X]] to half
 ; CHECK-NEXT:    [[R:%.*]] = fadd half [[XF]], 0xH57F8
 ; CHECK-NEXT:    ret half [[R]]
 ;
@@ -62,7 +62,7 @@ define half @test_ui_ui_i8_add_C_fail_no_repr(i8 noundef %x_in) {
 define half @test_ui_ui_i8_add_C_fail_overflow(i8 noundef %x_in) {
 ; CHECK-LABEL: @test_ui_ui_i8_add_C_fail_overflow(
 ; CHECK-NEXT:    [[X:%.*]] = and i8 [[X_IN:%.*]], 127
-; CHECK-NEXT:    [[XF:%.*]] = uitofp i8 [[X]] to half
+; CHECK-NEXT:    [[XF:%.*]] = uitofp nneg i8 [[X]] to half
 ; CHECK-NEXT:    [[R:%.*]] = fadd half [[XF]], 0xH5808
 ; CHECK-NEXT:    ret half [[R]]
 ;
@@ -110,7 +110,7 @@ define half @test_ui_si_i8_add(i8 noundef %x_in, i8 noundef %y_in) {
 ; CHECK-NEXT:    [[X:%.*]] = and i8 [[X_IN:%.*]], 63
 ; CHECK-NEXT:    [[Y:%.*]] = and i8 [[Y_IN:%.*]], 63
 ; CHECK-NEXT:    [[TMP1:%.*]] = add nuw nsw i8 [[X]], [[Y]]
-; CHECK-NEXT:    [[R:%.*]] = uitofp i8 [[TMP1]] to half
+; CHECK-NEXT:    [[R:%.*]] = uitofp nneg i8 [[TMP1]] to half
 ; CHECK-NEXT:    ret half [[R]]
 ;
   %x = and i8 %x_in, 63
@@ -140,7 +140,7 @@ define half @test_ui_si_i8_add_overflow(i8 noundef %x_in, i8 noundef %y_in) {
 define half @test_ui_ui_i8_sub_C(i8 noundef %x_in) {
 ; CHECK-LABEL: @test_ui_ui_i8_sub_C(
 ; CHECK-NEXT:    [[TMP1:%.*]] = and i8 [[X_IN:%.*]], 127
-; CHECK-NEXT:    [[R:%.*]] = uitofp i8 [[TMP1]] to half
+; CHECK-NEXT:    [[R:%.*]] = uitofp nneg i8 [[TMP1]] to half
 ; CHECK-NEXT:    ret half [[R]]
 ;
   %x = or i8 %x_in, 128
@@ -166,7 +166,7 @@ define half @test_si_si_i8_sub(i8 noundef %x_in, i8 noundef %y_in) {
 ; CHECK-NEXT:    [[X:%.*]] = and i8 [[X_IN:%.*]], 63
 ; CHECK-NEXT:    [[Y:%.*]] = or i8 [[Y_IN:%.*]], -64
 ; CHECK-NEXT:    [[TMP1:%.*]] = sub nsw i8 [[X]], [[Y]]
-; CHECK-NEXT:    [[R:%.*]] = sitofp i8 [[TMP1]] to half
+; CHECK-NEXT:    [[R:%.*]] = uitofp nneg i8 [[TMP1]] to half
 ; CHECK-NEXT:    ret half [[R]]
 ;
   %x = and i8 %x_in, 63
@@ -181,7 +181,7 @@ define half @test_si_si_i8_sub_fail_overflow(i8 noundef %x_in, i8 noundef %y_in)
 ; CHECK-LABEL: @test_si_si_i8_sub_fail_overflow(
 ; CHECK-NEXT:    [[X:%.*]] = and i8 [[X_IN:%.*]], 63
 ; CHECK-NEXT:    [[Y:%.*]] = or i8 [[Y_IN:%.*]], -65
-; CHECK-NEXT:    [[XF:%.*]] = sitofp i8 [[X]] to half
+; CHECK-NEXT:    [[XF:%.*]] = uitofp nneg i8 [[X]] to half
 ; CHECK-NEXT:    [[YF:%.*]] = sitofp i8 [[Y]] to half
 ; CHECK-NEXT:    [[R:%.*]] = fsub half [[XF]], [[YF]]
 ; CHECK-NEXT:    ret half [[R]]
@@ -198,7 +198,7 @@ define half @test_si_si_i8_sub_C(i8 noundef %x_in) {
 ; CHECK-LABEL: @test_si_si_i8_sub_C(
 ; CHECK-NEXT:    [[X:%.*]] = and i8 [[X_IN:%.*]], 63
 ; CHECK-NEXT:    [[TMP1:%.*]] = or disjoint i8 [[X]], 64
-; CHECK-NEXT:    [[R:%.*]] = sitofp i8 [[TMP1]] to half
+; CHECK-NEXT:    [[R:%.*]] = uitofp nneg i8 [[TMP1]] to half
 ; CHECK-NEXT:    ret half [[R]]
 ;
   %x = and i8 %x_in, 63
@@ -283,7 +283,7 @@ define half @test_ui_ui_i8_mul_C(i8 noundef %x_in) {
 define half @test_ui_ui_i8_mul_C_fail_overlow(i8 noundef %x_in) {
 ; CHECK-LABEL: @test_ui_ui_i8_mul_C_fail_overlow(
 ; CHECK-NEXT:    [[X:%.*]] = and i8 [[X_IN:%.*]], 14
-; CHECK-NEXT:    [[XF:%.*]] = uitofp i8 [[X]] to half
+; CHECK-NEXT:    [[XF:%.*]] = uitofp nneg i8 [[X]] to half
 ; CHECK-NEXT:    [[R:%.*]] = fmul half [[XF]], 0xH4CC0
 ; CHECK-NEXT:    ret half [[R]]
 ;
@@ -315,7 +315,7 @@ define half @test_si_si_i8_mul_fail_maybe_zero(i8 noundef %x_in, i8 noundef %y_i
 ; CHECK-LABEL: @test_si_si_i8_mul_fail_maybe_zero(
 ; CHECK-NEXT:    [[X:%.*]] = and i8 [[X_IN:%.*]], 7
 ; CHECK-NEXT:    [[Y:%.*]] = or i8 [[Y_IN:%.*]], -8
-; CHECK-NEXT:    [[XF:%.*]] = sitofp i8 [[X]] to half
+; CHECK-NEXT:    [[XF:%.*]] = uitofp nneg i8 [[X]] to half
 ; CHECK-NEXT:    [[YF:%.*]] = sitofp i8 [[Y]] to half
 ; CHECK-NEXT:    [[R:%.*]] = fmul half [[XF]], [[YF]]
 ; CHECK-NEXT:    ret half [[R]]
@@ -332,7 +332,7 @@ define half @test_si_si_i8_mul_C_fail_no_repr(i8 noundef %x_in) {
 ; CHECK-LABEL: @test_si_si_i8_mul_C_fail_no_repr(
 ; CHECK-NEXT:    [[XX:%.*]] = and i8 [[X_IN:%.*]], 6
 ; CHECK-NEXT:    [[X:%.*]] = or disjoint i8 [[XX]], 1
-; CHECK-NEXT:    [[XF:%.*]] = sitofp i8 [[X]] to half
+; CHECK-NEXT:    [[XF:%.*]] = uitofp nneg i8 [[X]] to half
 ; CHECK-NEXT:    [[R:%.*]] = fmul half [[XF]], 0x...
[truncated]

@goldsteinn goldsteinn mentioned this pull request Apr 10, 2024
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nikic
nikic approved these changes Apr 11, 2024
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LGTM

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nikic commented Apr 11, 2024

Can the implementation of foldFBinOpOfIntCastsFromSign be simplified to use nneg instead of KnownBits after this change?

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Can the implementation of foldFBinOpOfIntCastsFromSign be simplified to use nneg instead of KnownBits after this change?

yeah we could. Should I do a survey of existing folds first to ensure we don't incorrectly keep flags (like with trunc nuw/nsw) before integrating too deeply?

dtcxzyw added a commit to dtcxzyw/llvm-opt-benchmark that referenced this pull request Apr 11, 2024
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pre-commit: test PR88299
edefa24 
PR Link: llvm/llvm-project#88299
@dtcxzyw dtcxzyw mentioned this pull request Apr 11, 2024
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dtcxzyw
dtcxzyw reviewed Apr 11, 2024
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llvm/lib/Transforms/InstCombine/InstCombineCasts.cpp
if (Instruction *R = commonCastTransforms(CI))
return R;
if (isKnownNonNegative(CI.getOperand(0), SQ)) {
auto UI =
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Suggested change
auto UI =
auto *UI =

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@goldsteinn We always use auto * for pointers.

https://llvm.org/docs/CodingStandards.html#beware-unnecessary-copies-with-auto

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My mistake, ill push a fix.

dtcxzyw
dtcxzyw approved these changes Apr 11, 2024
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LGTM.

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nikic commented Apr 11, 2024

Can the implementation of foldFBinOpOfIntCastsFromSign be simplified to use nneg instead of KnownBits after this change?

yeah we could. Should I do a survey of existing folds first to ensure we don't incorrectly keep flags (like with trunc nuw/nsw) before integrating too deeply?

I don't think this is important for uitofp nneg, mainly because we only have very few folds for it, so there's just not a great deal of potential for things to go wrong...

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