AMDGPU: Make is.shared and is.private propagate poison (llvm#128617)

Author: arsenm

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)))

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
 ; --------------------------------------------------------------------