[PATCH] D122926: [X86][CostModel] Strip bitcasts when looking for store GEP operand
Arthur Eubanks via Phabricator via llvm-commits
llvm-commits at lists.llvm.org
Fri Apr 1 11:21:26 PDT 2022
aeubanks created this revision.
Herald added subscribers: pengfei, zzheng, hiraditya.
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This heuristic was introduced in D35888 <https://reviews.llvm.org/D35888>. Assuming it is correct, this
patch should make cost modeling a bit more robust.
Repository:
rG LLVM Github Monorepo
https://reviews.llvm.org/D122926
Files:
llvm/lib/Target/X86/X86TargetTransformInfo.cpp
llvm/test/Transforms/LoopUnroll/X86/store_cost.ll
Index: llvm/test/Transforms/LoopUnroll/X86/store_cost.ll
===================================================================
--- llvm/test/Transforms/LoopUnroll/X86/store_cost.ll
+++ llvm/test/Transforms/LoopUnroll/X86/store_cost.ll
@@ -46,7 +46,9 @@
store i32 %val4, i32* %xptr4
%val5 = add i32 %counter, 10
%xptr5 = getelementptr [1024 x i32], [1024 x i32]* %x05, i32 0, i32 %counter
- store i32 %val5, i32* %xptr5
+ %bc = bitcast i32* %xptr5 to i16*
+ %val5trunc = trunc i32 %val5 to i16
+ store i16 %val5trunc, i16* %bc
br label %loop.inc
loop.inc:
Index: llvm/lib/Target/X86/X86TargetTransformInfo.cpp
===================================================================
--- llvm/lib/Target/X86/X86TargetTransformInfo.cpp
+++ llvm/lib/Target/X86/X86TargetTransformInfo.cpp
@@ -3901,7 +3901,8 @@
if (auto *SI = dyn_cast_or_null<StoreInst>(I)) {
// Store instruction with index and scale costs 2 Uops.
// Check the preceding GEP to identify non-const indices.
- if (auto *GEP = dyn_cast<GetElementPtrInst>(SI->getPointerOperand())) {
+ if (auto *GEP = dyn_cast<GetElementPtrInst>(
+ SI->getPointerOperand()->stripPointerCasts())) {
if (!all_of(GEP->indices(), [](Value *V) { return isa<Constant>(V); }))
return TTI::TCC_Basic * 2;
}
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