[llvm] af4581e - [SLP] make commutative check apply only to binops; NFC

[Sanjay Patel via llvm-commits]

Author: Sanjay Patel
Date: 2020-08-30T10:55:44-04:00
New Revision: af4581e8ab1648ff4df0b7fe3769160e6b9f2617

URL: https://github.com/llvm/llvm-project/commit/af4581e8ab1648ff4df0b7fe3769160e6b9f2617
DIFF: https://github.com/llvm/llvm-project/commit/af4581e8ab1648ff4df0b7fe3769160e6b9f2617.diff

LOG: [SLP] make commutative check apply only to binops; NFC

As discussed in D86798, it's not clear if the caller code
works with a more liberal definition of "commutative" that
includes intrinsics like min/max. This makes the binop
restriction (current functionality is unchanged) explicit
until the code is audited/tested.

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 e5e3d3611d07..ec138bf2b7c8 100644
--- a/llvm/lib/Transforms/Vectorize/SLPVectorizer.cpp
+++ b/llvm/lib/Transforms/Vectorize/SLPVectorizer.cpp
@@ -235,11 +235,16 @@ static bool isSplat(ArrayRef<Value *> VL) {
   return true;
 }
 
-/// \returns True if \p I is commutative, handles CmpInst as well as Instruction.
+/// \returns True if \p I is commutative, handles CmpInst and BinaryOperator.
 static bool isCommutative(Instruction *I) {
-  if (auto *IC = dyn_cast<CmpInst>(I))
-    return IC->isCommutative();
-  return I->isCommutative();
+  if (auto *Cmp = dyn_cast<CmpInst>(I))
+    return Cmp->isCommutative();
+  if (auto *BO = dyn_cast<BinaryOperator>(I))
+    return BO->isCommutative();
+  // TODO: This should check for generic Instruction::isCommutative(), but
+  //       we need to confirm that the caller code correctly handles Intrinsics
+  //       for example (does not have 2 operands).
+  return false;
 }
 
 /// Checks if the vector of instructions can be represented as a shuffle, like: