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LoopVectorizer: Pass OperandValueKind information to the cost model

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Pass down the fact that an operand is going to be a vector of constants.

This should bring the performance of MultiSource/Benchmarks/PAQ8p/paq8p on x86
back. It had degraded to scalar performance due to my pervious shift cost change
that made all shifts expensive on x86.

radar://13576547

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@178809 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Arnold Schwaighofer 2013-04-04 23:26:27 +00:00
parent 2537f3c659
commit ac2cc0170f
2 changed files with 41 additions and 2 deletions
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15
lib/Transforms/Vectorize/LoopVectorize.cpp
View File

@ -3331,8 +3331,19 @@ LoopVectorizationCostModel::getInstructionCost(Instruction *I, unsigned VF) {
case Instruction::AShr:
case Instruction::And:
case Instruction::Or:
case Instruction::Xor:
return TTI.getArithmeticInstrCost(I->getOpcode(), VectorTy);
case Instruction::Xor: {
// Certain instructions can be cheaper to vectorize if they have a constant
// second vector operand. One example of this are shifts on x86.
TargetTransformInfo::OperandValueKind Op1VK =
TargetTransformInfo::OK_AnyValue;
TargetTransformInfo::OperandValueKind Op2VK =
TargetTransformInfo::OK_AnyValue;
if (isa<ConstantInt>(I->getOperand(1)))
Op2VK = TargetTransformInfo::OK_UniformConstantValue;
return TTI.getArithmeticInstrCost(I->getOpcode(), VectorTy, Op1VK, Op2VK);
}
case Instruction::Select: {
SelectInst *SI = cast<SelectInst>(I);
const SCEV *CondSCEV = SE->getSCEV(SI->getCondition());

28
test/Transforms/LoopVectorize/X86/constant-vector-operand.ll Normal file
View File

@ -0,0 +1,28 @@
; RUN: opt -mtriple=x86_64-apple-darwin -mcpu=core2 -loop-vectorize -dce -instcombine -S < %s | FileCheck %s
@B = common global [1024 x i32] zeroinitializer, align 16
@A = common global [1024 x i32] zeroinitializer, align 16
; We use to not vectorize this loop because the shift was deemed to expensive.
; Now that we differentiate shift cost base on the operand value kind, we will
; vectorize this loop.
; CHECK: ashr <4 x i32>
define void @f() {
entry:
br label %for.body
for.body:
%indvars.iv = phi i64 [ 0, %entry ], [ %indvars.iv.next, %for.body ]
%arrayidx = getelementptr inbounds [1024 x i32]* @B, i64 0, i64 %indvars.iv
%0 = load i32* %arrayidx, align 4
%shl = ashr i32 %0, 3
%arrayidx2 = getelementptr inbounds [1024 x i32]* @A, i64 0, i64 %indvars.iv
store i32 %shl, i32* %arrayidx2, align 4
%indvars.iv.next = add i64 %indvars.iv, 1
%lftr.wideiv = trunc i64 %indvars.iv.next to i32
%exitcond = icmp eq i32 %lftr.wideiv, 1024
br i1 %exitcond, label %for.end, label %for.body
for.end:
ret void
}