1 files changed, 29 insertions, 18 deletions
diff --git a/llvm/lib/Target/AMDGPU/AMDGPUInstCombineIntrinsic.cpp b/llvm/lib/Target/AMDGPU/AMDGPUInstCombineIntrinsic.cpp
index 9f8926432d00..e8674c4c7759 100644
--- a/llvm/lib/Target/AMDGPU/AMDGPUInstCombineIntrinsic.cpp
+++ b/llvm/lib/Target/AMDGPU/AMDGPUInstCombineIntrinsic.cpp
@@ -640,27 +640,38 @@ GCNTTIImpl::instCombineIntrinsic(InstCombiner &IC, IntrinsicInst &II) const {
     break;
   }
   case Intrinsic::amdgcn_cvt_pkrtz: {
-    Value *Src0 = II.getArgOperand(0);
-    Value *Src1 = II.getArgOperand(1);
-    if (const ConstantFP *C0 = dyn_cast<ConstantFP>(Src0)) {
-      if (const ConstantFP *C1 = dyn_cast<ConstantFP>(Src1)) {
-        const fltSemantics &HalfSem =
-            II.getType()->getScalarType()->getFltSemantics();
+    auto foldFPTruncToF16RTZ = [](Value *Arg) -> Value * {
+      Type *HalfTy = Type::getHalfTy(Arg->getContext());
+
+      if (isa<PoisonValue>(Arg))
+        return PoisonValue::get(HalfTy);
+      if (isa<UndefValue>(Arg))
+        return UndefValue::get(HalfTy);
+
+      ConstantFP *CFP = nullptr;
+      if (match(Arg, m_ConstantFP(CFP))) {
         bool LosesInfo;
-        APFloat Val0 = C0->getValueAPF();
-        APFloat Val1 = C1->getValueAPF();
-        Val0.convert(HalfSem, APFloat::rmTowardZero, &LosesInfo);
-        Val1.convert(HalfSem, APFloat::rmTowardZero, &LosesInfo);
-
-        Constant *Folded =
-            ConstantVector::get({ConstantFP::get(II.getContext(), Val0),
-                                 ConstantFP::get(II.getContext(), Val1)});
-        return IC.replaceInstUsesWith(II, Folded);
+        APFloat Val(CFP->getValueAPF());
+        Val.convert(APFloat::IEEEhalf(), APFloat::rmTowardZero, &LosesInfo);
+        return ConstantFP::get(HalfTy, Val);
       }
-    }
 
-    if (isa<UndefValue>(Src0) && isa<UndefValue>(Src1)) {
-      return IC.replaceInstUsesWith(II, UndefValue::get(II.getType()));
+      Value *Src = nullptr;
+      if (match(Arg, m_FPExt(m_Value(Src)))) {
+        if (Src->getType()->isHalfTy())
+          return Src;
+      }
+
+      return nullptr;
+    };
+
+    if (Value *Src0 = foldFPTruncToF16RTZ(II.getArgOperand(0))) {
+      if (Value *Src1 = foldFPTruncToF16RTZ(II.getArgOperand(1))) {
+        Value *V = PoisonValue::get(II.getType());
+        V = IC.Builder.CreateInsertElement(V, Src0, (uint64_t)0);
+        V = IC.Builder.CreateInsertElement(V, Src1, (uint64_t)1);
+        return IC.replaceInstUsesWith(II, V);
+      }
     }
 
     break;