SpeculativeExecution: Stop using whitelist for costs

Just let TTI's cost do this instead of arbitrarily restricting
this.

llvm-svn: 301950
This commit is contained in:
Matt Arsenault 2017-05-02 18:02:18 +00:00
parent 49f7e0a98b
commit 9ac7d6be3c
3 changed files with 106 additions and 42 deletions

View File

@ -208,47 +208,6 @@ bool SpeculativeExecutionPass::runOnBasicBlock(BasicBlock &B) {
return false;
}
static unsigned ComputeSpeculationCost(const Instruction *I,
const TargetTransformInfo &TTI) {
switch (Operator::getOpcode(I)) {
case Instruction::GetElementPtr:
case Instruction::Add:
case Instruction::Mul:
case Instruction::And:
case Instruction::Or:
case Instruction::Select:
case Instruction::Shl:
case Instruction::Sub:
case Instruction::LShr:
case Instruction::AShr:
case Instruction::Xor:
case Instruction::ZExt:
case Instruction::SExt:
case Instruction::Call:
case Instruction::BitCast:
case Instruction::PtrToInt:
case Instruction::IntToPtr:
case Instruction::AddrSpaceCast:
case Instruction::FPToUI:
case Instruction::FPToSI:
case Instruction::UIToFP:
case Instruction::SIToFP:
case Instruction::FPExt:
case Instruction::FPTrunc:
case Instruction::FAdd:
case Instruction::FSub:
case Instruction::FMul:
case Instruction::FDiv:
case Instruction::FRem:
case Instruction::ICmp:
case Instruction::FCmp:
return TTI.getUserCost(I);
default:
return UINT_MAX; // Disallow anything not whitelisted.
}
}
bool SpeculativeExecutionPass::considerHoistingFromTo(
BasicBlock &FromBlock, BasicBlock &ToBlock) {
SmallSet<const Instruction *, 8> NotHoisted;
@ -264,7 +223,7 @@ bool SpeculativeExecutionPass::considerHoistingFromTo(
unsigned TotalSpeculationCost = 0;
for (auto& I : FromBlock) {
const unsigned Cost = ComputeSpeculationCost(&I, *TTI);
const unsigned Cost = TTI->getUserCost(&I);
if (Cost != UINT_MAX && isSafeToSpeculativelyExecute(&I) &&
AllPrecedingUsesFromBlockHoisted(&I)) {
TotalSpeculationCost += Cost;

View File

@ -0,0 +1,32 @@
; RUN: opt < %s -S -speculative-execution \
; RUN: -spec-exec-max-speculation-cost 4 -spec-exec-max-not-hoisted 3 \
; RUN: | FileCheck %s
; CHECK-LABEL: @ifThen_extractvalue(
; CHECK: extractvalue
; CHECK: br i1 true
define void @ifThen_extractvalue() {
br i1 true, label %a, label %b
a:
%x = extractvalue { i32, i32 } undef, 0
br label %b
b:
ret void
}
; CHECK-LABEL: @ifThen_insertvalue(
; CHECK: insertvalue
; CHECK: br i1 true
define void @ifThen_insertvalue() {
br i1 true, label %a, label %b
a:
%x = insertvalue { i32, i32 } undef, i32 undef, 0
br label %b
b:
ret void
}

View File

@ -0,0 +1,73 @@
; RUN: opt < %s -S -speculative-execution \
; RUN: -spec-exec-max-speculation-cost 4 -spec-exec-max-not-hoisted 3 \
; RUN: | FileCheck %s
; CHECK-LABEL: @ifThen_extractelement_constindex(
; CHECK: extractelement
; CHECK: br i1 true
define void @ifThen_extractelement_constindex() {
br i1 true, label %a, label %b
a:
%x = extractelement <4 x i32> undef, i32 0
br label %b
b:
ret void
}
; CHECK-LABEL: @ifThen_extractelement_varindex(
; CHECK: extractelement
; CHECK: br i1 true
define void @ifThen_extractelement_varindex(i32 %idx) {
br i1 true, label %a, label %b
a:
%x = extractelement <4 x i32> undef, i32 %idx
br label %b
b:
ret void
}
; CHECK-LABEL: @ifThen_insertelement_constindex(
; CHECK: insertelement
; CHECK: br i1 true
define void @ifThen_insertelement_constindex() {
br i1 true, label %a, label %b
a:
%x = insertelement <4 x i32> undef, i32 undef, i32 0
br label %b
b:
ret void
}
; CHECK-LABEL: @ifThen_insertelement_varindex(
; CHECK: insertelement
; CHECK: br i1 true
define void @ifThen_insertelement_varindex(i32 %idx) {
br i1 true, label %a, label %b
a:
%x = insertelement <4 x i32> undef, i32 undef, i32 %idx
br label %b
b:
ret void
}
; CHECK-LABEL: @ifThen_shufflevector(
; CHECK: shufflevector
; CHECK: br i1 true
define void @ifThen_shufflevector() {
br i1 true, label %a, label %b
a:
%x = shufflevector <4 x i32> undef, <4 x i32> undef, <4 x i32> undef
br label %b
b:
ret void
}