[llvm] [SLPVectorizer][X86] Free load cost for stores with constant pointers (PR #118016)

[Antonio Frighetto via llvm-commits]

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@@ -5157,8 +5157,9 @@ InstructionCost X86TTIImpl::getMemoryOpCost(unsigned Opcode, Type *Src,
 
   InstructionCost Cost = 0;
 
-  // Add a cost for constant load to vector.
-  if (Opcode == Instruction::Store && OpInfo.isConstant())
+  // Add a cost for constant load to vector, if pointer is not a constant.
+  if (auto *SI = dyn_cast_or_null<StoreInst>(I);
+      SI && !isa<Constant>(SI->getPointerOperand()) && OpInfo.isConstant())
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antoniofrighetto wrote:

Sorry if I'm missing something, where is the Type being `<20 x i64>` in this case? AFAICT, there isn't any load associated to the store when the store address is constant in x86, as it should just be needed to compute the memory address.

https://github.com/llvm/llvm-project/pull/118016