[llvm] 6f3b88b - [VPlan] Move trunc ([s|z]ext A) simplifications to simplifyRecipe.

[Florian Hahn via llvm-commits]

Author: Florian Hahn
Date: 2023-11-16T21:17:10Z
New Revision: 6f3b88baa2ac9ec892ed3ad7dd64d0d537010bc5

URL: https://github.com/llvm/llvm-project/commit/6f3b88baa2ac9ec892ed3ad7dd64d0d537010bc5
DIFF: https://github.com/llvm/llvm-project/commit/6f3b88baa2ac9ec892ed3ad7dd64d0d537010bc5.diff

LOG: [VPlan] Move trunc ([s|z]ext A) simplifications to simplifyRecipe.

Split off simplification from D149903 as suggested.

This should be effectively NFC until D149903 lands.

Added: 
    

Modified: 
    llvm/lib/Transforms/Vectorize/VPlanTransforms.cpp

Removed: 
    


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diff  --git a/llvm/lib/Transforms/Vectorize/VPlanTransforms.cpp b/llvm/lib/Transforms/Vectorize/VPlanTransforms.cpp
index c55864de9c17086..0eaaa037ad5782f 100644
--- a/llvm/lib/Transforms/Vectorize/VPlanTransforms.cpp
+++ b/llvm/lib/Transforms/Vectorize/VPlanTransforms.cpp
@@ -816,15 +816,28 @@ static void simplifyRecipe(VPRecipeBase &R, VPTypeAnalysis &TypeInfo) {
     break;
   }
   case Instruction::Trunc: {
-    VPRecipeBase *Zext = R.getOperand(0)->getDefiningRecipe();
-    if (!Zext || getOpcodeForRecipe(*Zext) != Instruction::ZExt)
+    VPRecipeBase *Ext = R.getOperand(0)->getDefiningRecipe();
+    if (!Ext)
       break;
-    VPValue *A = Zext->getOperand(0);
+    unsigned ExtOpcode = getOpcodeForRecipe(*Ext);
+    if (ExtOpcode != Instruction::ZExt && ExtOpcode != Instruction::SExt)
+      break;
+    VPValue *A = Ext->getOperand(0);
     VPValue *Trunc = R.getVPSingleValue();
-    Type *TruncToTy = TypeInfo.inferScalarType(Trunc);
-    if (TruncToTy && TruncToTy == TypeInfo.inferScalarType(A))
+    Type *TruncTy = TypeInfo.inferScalarType(Trunc);
+    Type *ATy = TypeInfo.inferScalarType(A);
+    if (TruncTy == ATy) {
       Trunc->replaceAllUsesWith(A);
-
+    } else if (ATy->getScalarSizeInBits() < TruncTy->getScalarSizeInBits()) {
+      auto *VPC =
+          new VPWidenCastRecipe(Instruction::CastOps(ExtOpcode), A, TruncTy);
+      VPC->insertBefore(&R);
+      Trunc->replaceAllUsesWith(VPC);
+    } else if (ATy->getScalarSizeInBits() > TruncTy->getScalarSizeInBits()) {
+      auto *VPC = new VPWidenCastRecipe(Instruction::Trunc, A, TruncTy);
+      VPC->insertBefore(&R);
+      Trunc->replaceAllUsesWith(VPC);
+    }
 #ifndef NDEBUG
     // Verify that the cached type info is for both A and its users is still
     // accurate by comparing it to freshly computed types.