[llvm] 36e4a7e - [SLP]Fix PR79321: SLPVectorizer's PHICompare doesn't provide a strict

[Alexey Bataev via llvm-commits]

Author: Alexey Bataev
Date: 2024-01-24T13:46:05-08:00
New Revision: 36e4a7ecca8a79fe8960a1e2afa78fbbd643dc7f

URL: https://github.com/llvm/llvm-project/commit/36e4a7ecca8a79fe8960a1e2afa78fbbd643dc7f
DIFF: https://github.com/llvm/llvm-project/commit/36e4a7ecca8a79fe8960a1e2afa78fbbd643dc7f.diff

LOG: [SLP]Fix PR79321: SLPVectorizer's PHICompare doesn't provide a strict
weak ordering.
Try to make PHICompare to meat strict weak ordering criteria.

Added: 
    

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

Removed: 
    


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diff  --git a/llvm/lib/Transforms/Vectorize/SLPVectorizer.cpp b/llvm/lib/Transforms/Vectorize/SLPVectorizer.cpp
index b4bc0f38a699a7c..8689d80488475fc 100644
--- a/llvm/lib/Transforms/Vectorize/SLPVectorizer.cpp
+++ b/llvm/lib/Transforms/Vectorize/SLPVectorizer.cpp
@@ -15953,6 +15953,8 @@ bool SLPVectorizerPass::vectorizeChainsInBlock(BasicBlock *BB, BoUpSLP &R) {
     for (int I = 0, E = Opcodes1.size(); I < E; ++I) {
       // Undefs are compatible with any other value.
       if (isa<UndefValue>(Opcodes1[I]) || isa<UndefValue>(Opcodes2[I])) {
+        if (isa<UndefValue>(Opcodes1[I]) && isa<UndefValue>(Opcodes2[I]))
+          continue;
         if (isa<Instruction>(Opcodes1[I]))
           return true;
         if (isa<Instruction>(Opcodes2[I]))
@@ -15961,9 +15963,11 @@ bool SLPVectorizerPass::vectorizeChainsInBlock(BasicBlock *BB, BoUpSLP &R) {
           return true;
         if (isa<Constant>(Opcodes2[I]) && !isa<UndefValue>(Opcodes2[I]))
           return false;
-        if (isa<UndefValue>(Opcodes1[I]) && isa<UndefValue>(Opcodes2[I]))
-          continue;
-        return isa<UndefValue>(Opcodes2[I]);
+        if (isa<UndefValue>(Opcodes1[I]) && !isa<UndefValue>(Opcodes2[I]))
+          return false;
+        if (!isa<UndefValue>(Opcodes1[I]) && isa<UndefValue>(Opcodes2[I]))
+          return true;
+        continue;
       }
       if (auto *I1 = dyn_cast<Instruction>(Opcodes1[I]))
         if (auto *I2 = dyn_cast<Instruction>(Opcodes2[I])) {
@@ -15984,14 +15988,14 @@ bool SLPVectorizerPass::vectorizeChainsInBlock(BasicBlock *BB, BoUpSLP &R) {
           return I1->getOpcode() < I2->getOpcode();
         }
       if (isa<Constant>(Opcodes1[I]) && isa<Constant>(Opcodes2[I]))
-        return Opcodes1[I]->getValueID() < Opcodes2[I]->getValueID();
-      if (isa<Instruction>(Opcodes1[I]))
+        continue;
+      if (isa<Instruction>(Opcodes1[I]) && !isa<Instruction>(Opcodes2[I]))
         return true;
-      if (isa<Instruction>(Opcodes2[I]))
+      if (!isa<Instruction>(Opcodes1[I]) && isa<Instruction>(Opcodes2[I]))
         return false;
-      if (isa<Constant>(Opcodes1[I]))
+      if (isa<Constant>(Opcodes1[I]) && !isa<Constant>(Opcodes2[I]))
         return true;
-      if (isa<Constant>(Opcodes2[I]))
+      if (!isa<Constant>(Opcodes1[I]) && isa<Constant>(Opcodes2[I]))
         return false;
       if (Opcodes1[I]->getValueID() < Opcodes2[I]->getValueID())
         return true;