[llvm] 76afbf6 - [VPlan] Replace uses with new value in VPInstructionsToVPRecipe (NFC).

[Florian Hahn via llvm-commits]

Author: Florian Hahn
Date: 2021-01-25T19:38:08Z
New Revision: 76afbf60ed7fb48233c9af9f74f2e8399fd38214

URL: https://github.com/llvm/llvm-project/commit/76afbf60ed7fb48233c9af9f74f2e8399fd38214
DIFF: https://github.com/llvm/llvm-project/commit/76afbf60ed7fb48233c9af9f74f2e8399fd38214.diff

LOG: [VPlan] Replace uses with new value in VPInstructionsToVPRecipe (NFC).

Now that VPRecipeBase inherits from VPDef, we can always use the new
VPValue for replacement, if the recipe defines one. Given the recipes
that are supported at the moment, all new recipes must have either 0 or
1 defined values.

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 f5565c1e0feb..1a54603faf22 100644
--- a/llvm/lib/Transforms/Vectorize/VPlanTransforms.cpp
+++ b/llvm/lib/Transforms/Vectorize/VPlanTransforms.cpp
@@ -35,7 +35,6 @@ void VPlanTransforms::VPInstructionsToVPRecipes(
       Plan->addCBV(NCondBit);
     }
   }
-  VPValue DummyValue;
   for (VPBlockBase *Base : RPOT) {
     // Do not widen instructions in pre-header and exit blocks.
     if (Base->getNumPredecessors() == 0 || Base->getNumSuccessors() == 0)
@@ -49,6 +48,7 @@ void VPlanTransforms::VPInstructionsToVPRecipes(
       VPInstruction *VPInst = cast<VPInstruction>(Ingredient);
       Instruction *Inst = cast<Instruction>(VPInst->getUnderlyingValue());
       if (DeadInstructions.count(Inst)) {
+        VPValue DummyValue;
         VPInst->replaceAllUsesWith(&DummyValue);
         Ingredient->eraseFromParent();
         continue;
@@ -80,7 +80,11 @@ void VPlanTransforms::VPInstructionsToVPRecipes(
             new VPWidenRecipe(*Inst, Plan->mapToVPValues(Inst->operands()));
 
       NewRecipe->insertBefore(Ingredient);
-      VPInst->replaceAllUsesWith(&DummyValue);
+      if (NewRecipe->getNumDefinedValues() == 1)
+        VPInst->replaceAllUsesWith(NewRecipe->getVPValue());
+      else
+        assert(NewRecipe->getNumDefinedValues() == 0 &&
+               "Only recpies with zero or one defined values expected");
       Ingredient->eraseFromParent();
     }
   }