AMDGPU: Make cvt_pknorm and cvt_pk intrinsics propagate poison (#131059)

Author: arsenm

llvm/lib/Target/AMDGPU/AMDGPUInstCombineIntrinsic.cpp

@@ -719,6 +719,10 @@ GCNTTIImpl::instCombineIntrinsic(InstCombiner &IC, IntrinsicInst &II) const {
     Value *Src0 = II.getArgOperand(0);
     Value *Src1 = II.getArgOperand(1);
 
+    // TODO: Replace call with scalar operation if only one element is poison.
+    if (isa<PoisonValue>(Src0) && isa<PoisonValue>(Src1))
+      return IC.replaceInstUsesWith(II, PoisonValue::get(II.getType()));
+
     if (isa<UndefValue>(Src0) && isa<UndefValue>(Src1)) {
       return IC.replaceInstUsesWith(II, UndefValue::get(II.getType()));
     }

llvm/test/Transforms/InstCombine/AMDGPU/amdgcn-intrinsics.ll

@@ -1320,6 +1320,32 @@ define <2 x i16> @undef_cvt_pknorm_i16() {
   ret <2 x i16> %cvt
 }
 
+define <2 x i16> @poison_lhs_cvt_pknorm_i16(float %y) {
+; CHECK-LABEL: @poison_lhs_cvt_pknorm_i16(
+; CHECK-NEXT:    [[CVT:%.*]] = call <2 x i16> @llvm.amdgcn.cvt.pknorm.i16(float poison, float [[Y:%.*]])
+; CHECK-NEXT:    ret <2 x i16> [[CVT]]
+;
+  %cvt = call <2 x i16> @llvm.amdgcn.cvt.pknorm.i16(float poison, float %y)
+  ret <2 x i16> %cvt
+}
+
+define <2 x i16> @poison_rhs_cvt_pknorm_i16(float %x) {
+; CHECK-LABEL: @poison_rhs_cvt_pknorm_i16(
+; CHECK-NEXT:    [[CVT:%.*]] = call <2 x i16> @llvm.amdgcn.cvt.pknorm.i16(float [[X:%.*]], float poison)
+; CHECK-NEXT:    ret <2 x i16> [[CVT]]
+;
+  %cvt = call <2 x i16> @llvm.amdgcn.cvt.pknorm.i16(float %x, float poison)
+  ret <2 x i16> %cvt
+}
+
+define <2 x i16> @poison_cvt_pknorm_i16() {
+; CHECK-LABEL: @poison_cvt_pknorm_i16(
+; CHECK-NEXT:    ret <2 x i16> poison
+;
+  %cvt = call <2 x i16> @llvm.amdgcn.cvt.pknorm.i16(float poison, float poison)
+  ret <2 x i16> %cvt
+}
+
 ; --------------------------------------------------------------------
 ; llvm.amdgcn.cvt.pknorm.u16
 ; --------------------------------------------------------------------
@@ -1352,6 +1378,32 @@ define <2 x i16> @undef_cvt_pknorm_u16() {
   ret <2 x i16> %cvt
 }
 
+define <2 x i16> @poison_lhs_cvt_pknorm_u16(float %y) {
+; CHECK-LABEL: @poison_lhs_cvt_pknorm_u16(
+; CHECK-NEXT:    [[CVT:%.*]] = call <2 x i16> @llvm.amdgcn.cvt.pknorm.u16(float poison, float [[Y:%.*]])
+; CHECK-NEXT:    ret <2 x i16> [[CVT]]
+;
+  %cvt = call <2 x i16> @llvm.amdgcn.cvt.pknorm.u16(float poison, float %y)
+  ret <2 x i16> %cvt
+}
+
+define <2 x i16> @poison_rhs_cvt_pknorm_u16(float %x) {
+; CHECK-LABEL: @poison_rhs_cvt_pknorm_u16(
+; CHECK-NEXT:    [[CVT:%.*]] = call <2 x i16> @llvm.amdgcn.cvt.pknorm.u16(float [[X:%.*]], float poison)
+; CHECK-NEXT:    ret <2 x i16> [[CVT]]
+;
+  %cvt = call <2 x i16> @llvm.amdgcn.cvt.pknorm.u16(float %x, float poison)
+  ret <2 x i16> %cvt
+}
+
+define <2 x i16> @poison_cvt_pknorm_u16() {
+; CHECK-LABEL: @poison_cvt_pknorm_u16(
+; CHECK-NEXT:    ret <2 x i16> poison
+;
+  %cvt = call <2 x i16> @llvm.amdgcn.cvt.pknorm.u16(float poison, float poison)
+  ret <2 x i16> %cvt
+}
+
 ; --------------------------------------------------------------------
 ; llvm.amdgcn.cvt.pk.i16
 ; --------------------------------------------------------------------
@@ -1384,6 +1436,32 @@ define <2 x i16> @undef_cvt_pk_i16() {
   ret <2 x i16> %cvt
 }
 
+define <2 x i16> @poison_lhs_cvt_pk_i16(i32 %y) {
+; CHECK-LABEL: @poison_lhs_cvt_pk_i16(
+; CHECK-NEXT:    [[CVT:%.*]] = call <2 x i16> @llvm.amdgcn.cvt.pk.i16(i32 poison, i32 [[Y:%.*]])
+; CHECK-NEXT:    ret <2 x i16> [[CVT]]
+;
+  %cvt = call <2 x i16> @llvm.amdgcn.cvt.pk.i16(i32 poison, i32 %y)
+  ret <2 x i16> %cvt
+}
+
+define <2 x i16> @poison_rhs_cvt_pk_i16(i32 %x) {
+; CHECK-LABEL: @poison_rhs_cvt_pk_i16(
+; CHECK-NEXT:    [[CVT:%.*]] = call <2 x i16> @llvm.amdgcn.cvt.pk.i16(i32 [[X:%.*]], i32 poison)
+; CHECK-NEXT:    ret <2 x i16> [[CVT]]
+;
+  %cvt = call <2 x i16> @llvm.amdgcn.cvt.pk.i16(i32 %x, i32 poison)
+  ret <2 x i16> %cvt
+}
+
+define <2 x i16> @poison_cvt_pk_i16() {
+; CHECK-LABEL: @poison_cvt_pk_i16(
+; CHECK-NEXT:    ret <2 x i16> poison
+;
+  %cvt = call <2 x i16> @llvm.amdgcn.cvt.pk.i16(i32 poison, i32 poison)
+  ret <2 x i16> %cvt
+}
+
 ; --------------------------------------------------------------------
 ; llvm.amdgcn.cvt.pk.u16
 ; --------------------------------------------------------------------
@@ -1416,6 +1494,32 @@ define <2 x i16> @undef_cvt_pk_u16() {
   ret <2 x i16> %cvt
 }
 
+define <2 x i16> @poison_lhs_cvt_pk_u16(i32 %y) {
+; CHECK-LABEL: @poison_lhs_cvt_pk_u16(
+; CHECK-NEXT:    [[CVT:%.*]] = call <2 x i16> @llvm.amdgcn.cvt.pk.u16(i32 poison, i32 [[Y:%.*]])
+; CHECK-NEXT:    ret <2 x i16> [[CVT]]
+;
+  %cvt = call <2 x i16> @llvm.amdgcn.cvt.pk.u16(i32 poison, i32 %y)
+  ret <2 x i16> %cvt
+}
+
+define <2 x i16> @poison_rhs_cvt_pk_u16(i32 %x) {
+; CHECK-LABEL: @poison_rhs_cvt_pk_u16(
+; CHECK-NEXT:    [[CVT:%.*]] = call <2 x i16> @llvm.amdgcn.cvt.pk.u16(i32 [[X:%.*]], i32 poison)
+; CHECK-NEXT:    ret <2 x i16> [[CVT]]
+;
+  %cvt = call <2 x i16> @llvm.amdgcn.cvt.pk.u16(i32 %x, i32 poison)
+  ret <2 x i16> %cvt
+}
+
+define <2 x i16> @poison_cvt_pk_u16() {
+; CHECK-LABEL: @poison_cvt_pk_u16(
+; CHECK-NEXT:    ret <2 x i16> poison
+;
+  %cvt = call <2 x i16> @llvm.amdgcn.cvt.pk.u16(i32 poison, i32 poison)
+  ret <2 x i16> %cvt
+}
+
 ; --------------------------------------------------------------------
 ; llvm.amdgcn.ubfe
 ; --------------------------------------------------------------------