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| author | Guozhi Wei <carrot@google.com> | 2017-09-15 22:28:12 +0000 |
|---|---|---|
| committer | Guozhi Wei <carrot@google.com> | 2017-09-15 22:28:12 +0000 |
| commit | 3d1305f6da8dbaa16716793f260d3d0edfb9fcd5 (patch) | |
| tree | a81a68724066f198e63203a8994da74f80251df1 | |
| parent | beb22b543718734ae62fc7325aa73d6708b2a42f (diff) | |
| download | bcm5719-llvm-3d1305f6da8dbaa16716793f260d3d0edfb9fcd5.tar.gz bcm5719-llvm-3d1305f6da8dbaa16716793f260d3d0edfb9fcd5.zip | |
[TargetTransformInfo] Static alloca has 0 cost
Static alloca usually doesn't generate any machine instructions, so it has 0 cost.
Differential Revision: https://reviews.llvm.org/D37879
llvm-svn: 313410
| -rw-r--r-- | llvm/include/llvm/Analysis/TargetTransformInfoImpl.h | 5 | ||||
| -rw-r--r-- | llvm/test/Analysis/CostModel/X86/costmodel.ll | 8 |
2 files changed, 13 insertions, 0 deletions
diff --git a/llvm/include/llvm/Analysis/TargetTransformInfoImpl.h b/llvm/include/llvm/Analysis/TargetTransformInfoImpl.h index 2191bd16456..63b47ffa3a5 100644 --- a/llvm/include/llvm/Analysis/TargetTransformInfoImpl.h +++ b/llvm/include/llvm/Analysis/TargetTransformInfoImpl.h @@ -740,6 +740,11 @@ public: if (isa<PHINode>(U)) return TTI::TCC_Free; // Model all PHI nodes as free. + // Static alloca doesn't generate target instructions. + if (auto *A = dyn_cast<AllocaInst>(U)) + if (A->isStaticAlloca()) + return TTI::TCC_Free; + if (const GEPOperator *GEP = dyn_cast<GEPOperator>(U)) { return static_cast<T *>(this)->getGEPCost(GEP->getSourceElementType(), GEP->getPointerOperand(), diff --git a/llvm/test/Analysis/CostModel/X86/costmodel.ll b/llvm/test/Analysis/CostModel/X86/costmodel.ll index f7958580b13..d16cc27cb16 100644 --- a/llvm/test/Analysis/CostModel/X86/costmodel.ll +++ b/llvm/test/Analysis/CostModel/X86/costmodel.ll @@ -7,6 +7,14 @@ target datalayout = "e-p:64:64:64-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:64:64-f3 define i64 @foo(i64 %arg) { + ; LATENCY: cost of 0 {{.*}} alloca i32 + ; CODESIZE: cost of 0 {{.*}} alloca i32 + %A1 = alloca i32, align 8 + + ; LATENCY: cost of 1 {{.*}} alloca i64, i64 undef + ; CODESIZE: cost of 1 {{.*}} alloca i64, i64 undef + %A2 = alloca i64, i64 undef, align 8 + ; LATENCY: cost of 1 {{.*}} %I64 = add ; CODESIZE: cost of 1 {{.*}} %I64 = add %I64 = add i64 undef, undef |
