This is an archive of the discontinued LLVM Phabricator instance.

Differential D81549

[LVI] Make use of 'assume'-provided data-part1
AbandonedPublic

Authored by junparser on Jun 10 2020, 4:49 AM.

Details

Reviewers
lebedev.ri
fhahn
nikic
reames
efriedma
Summary

This part 1 of D81544.
It combines assumptions with value range when solve selectInst in solveBlockValueSelect.

Diff Detail

Revision Contents

PathSize
llvm/
lib/
Analysis/
4 lines
test/
Transforms/
JumpThreading/
26 lines

Diff 269794

llvm/lib/Analysis/LazyValueInfo.cpp

Show First 20 Lines • Show All 813 Lines • ▼ Show 20 Lines
Optional<ValueLatticeElement> LazyValueInfoImpl::solveBlockValueSelect( Optional<ValueLatticeElement> LazyValueInfoImpl::solveBlockValueSelect(
SelectInst *SI, BasicBlock *BB) { SelectInst *SI, BasicBlock *BB) {
// Recurse on our inputs if needed // Recurse on our inputs if needed
Optional<ValueLatticeElement> OptTrueVal = Optional<ValueLatticeElement> OptTrueVal =
getBlockValue(SI->getTrueValue(), BB); getBlockValue(SI->getTrueValue(), BB);
if (!OptTrueVal) if (!OptTrueVal)
return None; return None;
ValueLatticeElement &TrueVal = *OptTrueVal; ValueLatticeElement &TrueVal = *OptTrueVal;
intersectAssumeOrGuardBlockValueConstantRange(SI->getTrueValue(), TrueVal,
SI);
// If we hit overdefined, don't ask more queries. We want to avoid poisoning // If we hit overdefined, don't ask more queries. We want to avoid poisoning
// extra slots in the table if we can. // extra slots in the table if we can.
if (TrueVal.isOverdefined()) if (TrueVal.isOverdefined())
return ValueLatticeElement::getOverdefined(); return ValueLatticeElement::getOverdefined();
Optional<ValueLatticeElement> OptFalseVal = Optional<ValueLatticeElement> OptFalseVal =
getBlockValue(SI->getFalseValue(), BB); getBlockValue(SI->getFalseValue(), BB);
if (!OptFalseVal) if (!OptFalseVal)
return None; return None;
ValueLatticeElement &FalseVal = *OptFalseVal; ValueLatticeElement &FalseVal = *OptFalseVal;
intersectAssumeOrGuardBlockValueConstantRange(SI->getFalseValue(), FalseVal,
SI);
// If we hit overdefined, don't ask more queries. We want to avoid poisoning // If we hit overdefined, don't ask more queries. We want to avoid poisoning
// extra slots in the table if we can. // extra slots in the table if we can.
if (FalseVal.isOverdefined()) if (FalseVal.isOverdefined())
return ValueLatticeElement::getOverdefined(); return ValueLatticeElement::getOverdefined();
if (TrueVal.isConstantRange() && FalseVal.isConstantRange()) { if (TrueVal.isConstantRange() && FalseVal.isConstantRange()) {
const ConstantRange &TrueCR = TrueVal.getConstantRange(); const ConstantRange &TrueCR = TrueVal.getConstantRange();
▲ Show 20 Lines • Show All 1,124 Lines • Show Last 20 Lines

llvm/test/Transforms/JumpThreading/assume.ll

Show First 20 Lines • Show All 223 Lines • ▼ Show 20 Lines
normal: normal:
ret void ret void
error: error:
store atomic i32 0, i32* @g unordered, align 4 store atomic i32 0, i32* @g unordered, align 4
ret void ret void
} }
define void @can_fold_assume5(i32, i32, i1 zeroext, i1 %cond) {
; CHECK-LABEL: can_fold_assume5
; CHECK: @llvm.assume
; CHECK: @llvm.assume
; CHECK-NOT: @dummy(i1 true)
%4 = icmp slt i32 %0, 234
tail call void @llvm.assume(i1 %4)
%5 = icmp sgt i32 %1, 789
tail call void @llvm.assume(i1 %5)
%6 = select i1 %2, i32 %0, i32 %1
%7 = add i32 %6, -234
br i1 %cond, label %label0, label %label2
label0:
%8 = icmp ult i32 %7, 556
br i1 %8, label %label1, label %label2
label1:
tail call void @dummy(i1 true)
br label %label2
label2:
ret void
}
; Function Attrs: nounwind ; Function Attrs: nounwind
declare void @llvm.assume(i1) #1 declare void @llvm.assume(i1) #1
declare void @bar(...) declare void @bar(...)
declare void @car(...) declare void @car(...)
attributes #0 = { nounwind uwtable } attributes #0 = { nounwind uwtable }
attributes #1 = { nounwind } attributes #1 = { nounwind }