AMDGPU: Make fma_legacy intrinsic propagate poison

[arsenm]

No description provided.

[arsenm]

• AMDGPU: Make fma_legacy intrinsic propagate poison #131063 👈 (View in Graphite)
• AMDGPU: Make fmul_legacy intrinsic propagate poison #131062
• AMDGPU: Make ballot intrinsic propagate poison #131061
• AMDGPU: Make fmed3 intrinsic propagate poison #131060
• AMDGPU: Make cvt_pknorm and cvt_pk intrinsics propagate poison #131059
• main

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[llvmbot]

@llvm/pr-subscribers-llvm-transforms

@llvm/pr-subscribers-backend-amdgpu

Author: Matt Arsenault (arsenm)

Changes

---

Full diff: https://github.com/llvm/llvm-project/pull/131063.diff

2 Files Affected:

• (modified) llvm/lib/Target/AMDGPU/AMDGPUInstCombineIntrinsic.cpp (+5)
• (modified) llvm/test/Transforms/InstCombine/AMDGPU/fma_legacy.ll (+24)

diff --git a/llvm/lib/Target/AMDGPU/AMDGPUInstCombineIntrinsic.cpp b/llvm/lib/Target/AMDGPU/AMDGPUInstCombineIntrinsic.cpp
index ba4e6e530fe56..86f33f33d1fc7 100644
--- a/llvm/lib/Target/AMDGPU/AMDGPUInstCombineIntrinsic.cpp
+++ b/llvm/lib/Target/AMDGPU/AMDGPUInstCombineIntrinsic.cpp
@@ -1281,6 +1281,11 @@ GCNTTIImpl::instCombineIntrinsic(InstCombiner &IC, IntrinsicInst &II) const {
     Value *Op1 = II.getArgOperand(1);
     Value *Op2 = II.getArgOperand(2);
 
+    for (Value *Src : {Op0, Op1, Op2}) {
+      if (isa<PoisonValue>(Src))
+        return IC.replaceInstUsesWith(II, Src);
+    }
+
     // The legacy behaviour is that multiplying +/-0.0 by anything, even NaN or
     // infinity, gives +0.0.
     // TODO: Move to InstSimplify?
diff --git a/llvm/test/Transforms/InstCombine/AMDGPU/fma_legacy.ll b/llvm/test/Transforms/InstCombine/AMDGPU/fma_legacy.ll
index 72bffe62fbb14..b2f851d6d56ed 100644
--- a/llvm/test/Transforms/InstCombine/AMDGPU/fma_legacy.ll
+++ b/llvm/test/Transforms/InstCombine/AMDGPU/fma_legacy.ll
@@ -105,6 +105,30 @@ define float @test_finite_assumed(float %x, float %y, float %z) {
   ret float %call
 }
 
+define float @test_poison_x_y(float %x, float %y) {
+; CHECK-LABEL: @test_poison_x_y(
+; CHECK-NEXT:    ret float poison
+;
+  %call = call float @llvm.amdgcn.fma.legacy(float poison, float %x, float %y)
+  ret float %call
+}
+
+define float @test_x_poison_y(float %x, float %y) {
+; CHECK-LABEL: @test_x_poison_y(
+; CHECK-NEXT:    ret float poison
+;
+  %call = call float @llvm.amdgcn.fma.legacy(float %x, float poison, float %y)
+  ret float %call
+}
+
+define float @test_x_y_poison_y(float %x, float %y) {
+; CHECK-LABEL: @test_x_y_poison_y(
+; CHECK-NEXT:    ret float poison
+;
+  %call = call float @llvm.amdgcn.fma.legacy(float %x, float %y, float poison)
+  ret float %call
+}
+
 declare float @llvm.amdgcn.fma.legacy(float, float, float)
 declare float @llvm.fabs.f32(float)
 declare void @llvm.assume(i1 noundef)

[arsenm]

Merge activity

• Mar 14, 12:23 AM EDT: A user started a stack merge that includes this pull request via Graphite.
• Mar 14, 12:40 AM EDT: Graphite rebased this pull request as part of a merge.
• Mar 14, 12:42 AM EDT: A user merged this pull request with Graphite.