AMDGPU: Make is.shared and is.private propagate poison

[arsenm]

No description provided.

[arsenm]

• AMDGPU: Make is.shared and is.private propagate poison #128617 👈 (View in Graphite)
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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/128617.diff

2 Files Affected:

• (modified) llvm/lib/Target/AMDGPU/AMDGPUInstCombineIntrinsic.cpp (+4-1)
• (modified) llvm/test/Transforms/InstCombine/AMDGPU/amdgcn-intrinsics.ll (+16)

diff --git a/llvm/lib/Target/AMDGPU/AMDGPUInstCombineIntrinsic.cpp b/llvm/lib/Target/AMDGPU/AMDGPUInstCombineIntrinsic.cpp
index bac3bb5fde7b0..ebc00e59584ac 100644
--- a/llvm/lib/Target/AMDGPU/AMDGPUInstCombineIntrinsic.cpp
+++ b/llvm/lib/Target/AMDGPU/AMDGPUInstCombineIntrinsic.cpp
@@ -1256,7 +1256,10 @@ GCNTTIImpl::instCombineIntrinsic(InstCombiner &IC, IntrinsicInst &II) const {
   }
   case Intrinsic::amdgcn_is_shared:
   case Intrinsic::amdgcn_is_private: {
-    if (isa<UndefValue>(II.getArgOperand(0)))
+    Value *Src = II.getArgOperand(0);
+    if (isa<PoisonValue>(Src))
+      return IC.replaceInstUsesWith(II, PoisonValue::get(II.getType()));
+    if (isa<UndefValue>(Src))
       return IC.replaceInstUsesWith(II, UndefValue::get(II.getType()));
 
     if (isa<ConstantPointerNull>(II.getArgOperand(0)))
diff --git a/llvm/test/Transforms/InstCombine/AMDGPU/amdgcn-intrinsics.ll b/llvm/test/Transforms/InstCombine/AMDGPU/amdgcn-intrinsics.ll
index 5fdb918c87545..aafe8105482d2 100644
--- a/llvm/test/Transforms/InstCombine/AMDGPU/amdgcn-intrinsics.ll
+++ b/llvm/test/Transforms/InstCombine/AMDGPU/amdgcn-intrinsics.ll
@@ -5671,6 +5671,14 @@ define i1 @test_is_shared_undef() nounwind {
   ret i1 %val
 }
 
+define i1 @test_is_shared_poison() nounwind {
+; CHECK-LABEL: @test_is_shared_poison(
+; CHECK-NEXT:    ret i1 poison
+;
+  %val = call i1 @llvm.amdgcn.is.shared(ptr poison)
+  ret i1 %val
+}
+
 ; --------------------------------------------------------------------
 ; llvm.amdgcn.is.private
 ; --------------------------------------------------------------------
@@ -5693,6 +5701,14 @@ define i1 @test_is_private_undef() nounwind {
   ret i1 %val
 }
 
+define i1 @test_is_private_poison() nounwind {
+; CHECK-LABEL: @test_is_private_poison(
+; CHECK-NEXT:    ret i1 poison
+;
+  %val = call i1 @llvm.amdgcn.is.private(ptr poison)
+  ret i1 %val
+}
+
 ; --------------------------------------------------------------------
 ; llvm.amdgcn.trig.preop
 ; --------------------------------------------------------------------

[shiltian]

It looks good but what is the benefit of doing it?

[arsenm]

It looks good but what is the benefit of doing it?

poison folds out better and we want to get rid of undef