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Differential D60497

[InstCombine] Handle saddo always overflow
ClosedPublic

Authored by nikic on Apr 10 2019, 12:14 AM.

Details

Reviewers
lebedev.ri
spatel
Commits
rGef23e8848051: [InstCombine] Handle saddo always overflow
rL358095: [InstCombine] Handle saddo always overflow
Summary

Followup to D60483: Handle always overflow condition for saddo.

Diff Detail

Repository
rL LLVM

Event Timeline

nikic created this revision.Apr 10 2019, 12:14 AM
Herald added a project: Restricted Project. · View Herald TranscriptApr 10 2019, 12:14 AM
Herald added subscribers: llvm-commits, hiraditya. · View Herald Transcript
lebedev.ri accepted this revision.Apr 10 2019, 2:50 AM

LG, thank you

This revision is now accepted and ready to land.Apr 10 2019, 2:50 AM
Closed by commit rL358095: [InstCombine] Handle saddo always overflow (authored by nikic). · Explain WhyApr 10 2019, 9:17 AM
This revision was automatically updated to reflect the committed changes.
nikic mentioned this in D60518: [InstCombine] Handle ssubo always overflow.Apr 10 2019, 9:18 AM
nikic mentioned this in rL358100: [InstCombine] Handle ssubo always overflow.Apr 10 2019, 9:31 AM
nikic mentioned this in rG0a8228fd28ee: [InstCombine] Handle ssubo always overflow.

Revision Contents

PathSize
llvm/
trunk/
lib/
Transforms/
InstCombine/
6 lines
test/
Transforms/
InstCombine/
5 lines

Diff 194532

llvm/trunk/lib/Transforms/InstCombine/InstCombineCompares.cpp

Show First 20 Lines • Show All 3,967 Lines • ▼ Show 20 Lines if (match(RHS, m_Zero()))
return SetResult(LHS, Builder.getFalse(), false); return SetResult(LHS, Builder.getFalse(), false);
OverflowResult OR; OverflowResult OR;
if (OCF == OCF_UNSIGNED_ADD) { if (OCF == OCF_UNSIGNED_ADD) {
OR = computeOverflowForUnsignedAdd(LHS, RHS, &OrigI); OR = computeOverflowForUnsignedAdd(LHS, RHS, &OrigI);
if (OR == OverflowResult::NeverOverflows) if (OR == OverflowResult::NeverOverflows)
return SetResult(Builder.CreateNUWAdd(LHS, RHS), Builder.getFalse(), return SetResult(Builder.CreateNUWAdd(LHS, RHS), Builder.getFalse(),
true); true);
if (OR == OverflowResult::AlwaysOverflows)
return SetResult(Builder.CreateAdd(LHS, RHS), Builder.getTrue(), true);
} else { } else {
OR = computeOverflowForSignedAdd(LHS, RHS, &OrigI); OR = computeOverflowForSignedAdd(LHS, RHS, &OrigI);
if (OR == OverflowResult::NeverOverflows) if (OR == OverflowResult::NeverOverflows)
return SetResult(Builder.CreateNSWAdd(LHS, RHS), Builder.getFalse(), return SetResult(Builder.CreateNSWAdd(LHS, RHS), Builder.getFalse(),
true); true);
} }
if (OR == OverflowResult::AlwaysOverflows)
return SetResult(Builder.CreateAdd(LHS, RHS), Builder.getTrue(), true);
break; break;
} }
case OCF_UNSIGNED_SUB: case OCF_UNSIGNED_SUB:
case OCF_SIGNED_SUB: { case OCF_SIGNED_SUB: {
// X - 0 -> {X, false} // X - 0 -> {X, false}
if (match(RHS, m_Zero())) if (match(RHS, m_Zero()))
return SetResult(LHS, Builder.getFalse(), false); return SetResult(LHS, Builder.getFalse(), false);
▲ Show 20 Lines • Show All 1,640 Lines • Show Last 20 Lines

llvm/trunk/test/Transforms/InstCombine/with_overflow.ll

Show First 20 Lines • Show All 562 Lines • ▼ Show 20 Lines;
%a = call { i8, i1 } @llvm.umul.with.overflow.i8(i8 %y, i8 2) %a = call { i8, i1 } @llvm.umul.with.overflow.i8(i8 %y, i8 2)
ret { i8, i1 } %a ret { i8, i1 } %a
} }
define { i8, i1 } @sadd_always_overflow(i8 %x) nounwind { define { i8, i1 } @sadd_always_overflow(i8 %x) nounwind {
; CHECK-LABEL: @sadd_always_overflow( ; CHECK-LABEL: @sadd_always_overflow(
; CHECK-NEXT: [[C:%.*]] = icmp sgt i8 [[X:%.*]], 100 ; CHECK-NEXT: [[C:%.*]] = icmp sgt i8 [[X:%.*]], 100
; CHECK-NEXT: [[Y:%.*]] = select i1 [[C]], i8 [[X]], i8 100 ; CHECK-NEXT: [[Y:%.*]] = select i1 [[C]], i8 [[X]], i8 100
; CHECK-NEXT: [[A:%.*]] = call { i8, i1 } @llvm.sadd.with.overflow.i8(i8 [[Y]], i8 28) ; CHECK-NEXT: [[A:%.*]] = add nuw i8 [[Y]], 28
; CHECK-NEXT: ret { i8, i1 } [[A]] ; CHECK-NEXT: [[TMP1:%.*]] = insertvalue { i8, i1 } { i8 undef, i1 true }, i8 [[A]], 0
; CHECK-NEXT: ret { i8, i1 } [[TMP1]]
; ;
%c = icmp sgt i8 %x, 100 %c = icmp sgt i8 %x, 100
%y = select i1 %c, i8 %x, i8 100 %y = select i1 %c, i8 %x, i8 100
%a = call { i8, i1 } @llvm.sadd.with.overflow.i8(i8 %y, i8 28) %a = call { i8, i1 } @llvm.sadd.with.overflow.i8(i8 %y, i8 28)
ret { i8, i1 } %a ret { i8, i1 } %a
} }
define { i8, i1 } @ssub_always_overflow(i8 %x) nounwind { define { i8, i1 } @ssub_always_overflow(i8 %x) nounwind {
Show All 24 Lines