SLPVectorizer: Take credit for free extractelement instructions

Extract element instructions that will be removed when vectorzing lower the
cost.

Patch by Arch D. Robison!

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@205020 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Arnold Schwaighofer 2014-03-28 17:21:32 +00:00
parent aa0a2a35f8
commit ce36237826
2 changed files with 36 additions and 2 deletions

View File

@ -1015,8 +1015,17 @@ int BoUpSLP::getEntryCost(TreeEntry *E) {
return 0;
}
case Instruction::ExtractElement: {
if (CanReuseExtract(VL))
return 0;
if (CanReuseExtract(VL)) {
int DeadCost = 0;
for (unsigned i = 0, e = VL.size(); i < e; ++i) {
ExtractElementInst *E = cast<ExtractElementInst>(VL[i]);
if (E->hasOneUse())
// Take credit for instruction that will become dead.
DeadCost +=
TTI->getVectorInstrCost(Instruction::ExtractElement, VecTy, i);
}
return -DeadCost;
}
return getGatherCost(VecTy);
}
case Instruction::ZExt:

View File

@ -1,4 +1,5 @@
; RUN: opt -S -slp-vectorizer -slp-threshold=-10000 < %s | FileCheck %s
; RUN: opt -S -slp-vectorizer -slp-threshold=0 < %s | FileCheck %s -check-prefix=ZEROTHRESH
target datalayout = "e-p:64:64:64-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:64:64-f32:32:32-f64:64:64-v64:64:64-v128:128:128-a0:0:64-s0:64:64-n8:16:32:64-S128"
target triple = "x86_64-apple-macosx10.8.0"
@ -218,4 +219,28 @@ define <4 x float> @reschedule_extract(<4 x float> %a, <4 x float> %b) {
ret <4 x float> %v3
}
; Check that cost model for vectorization takes credit for
; instructions that are erased.
define <4 x float> @take_credit(<4 x float> %a, <4 x float> %b) {
; ZEROTHRESH-LABEL: @take_credit(
; ZEROTHRESH-CHECK: %1 = fadd <4 x float> %a, %b
%a0 = extractelement <4 x float> %a, i32 0
%b0 = extractelement <4 x float> %b, i32 0
%c0 = fadd float %a0, %b0
%a1 = extractelement <4 x float> %a, i32 1
%b1 = extractelement <4 x float> %b, i32 1
%c1 = fadd float %a1, %b1
%a2 = extractelement <4 x float> %a, i32 2
%b2 = extractelement <4 x float> %b, i32 2
%c2 = fadd float %a2, %b2
%a3 = extractelement <4 x float> %a, i32 3
%b3 = extractelement <4 x float> %b, i32 3
%c3 = fadd float %a3, %b3
%v0 = insertelement <4 x float> undef, float %c0, i32 0
%v1 = insertelement <4 x float> %v0, float %c1, i32 1
%v2 = insertelement <4 x float> %v1, float %c2, i32 2
%v3 = insertelement <4 x float> %v2, float %c3, i32 3
ret <4 x float> %v3
}
attributes #0 = { nounwind ssp uwtable "less-precise-fpmad"="false" "no-frame-pointer-elim"="true" "no-frame-pointer-elim-non-leaf"="true" "no-infs-fp-math"="false" "no-nans-fp-math"="false" "stack-protector-buffer-size"="8" "unsafe-fp-math"="false" "use-soft-float"="false" }