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Differential D120004

[SCEVExpander][OpaquePtr] Check GEP source type when finding identical GEP
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Authored by aeubanks on Feb 16 2022, 8:45 PM.

Details

Reviewers
nikic
Group Reviewers
Restricted Project
Commits
rG129af4daa7ce: [SCEVExpander][OpaquePtr] Check GEP source type when finding identical GEP
Summary

Fixes an opaque pointers miscompile.

Diff Detail

Event Timeline

aeubanks created this revision.Feb 16 2022, 8:45 PM
Herald added a subscriber: hiraditya. · View Herald TranscriptFeb 16 2022, 8:45 PM
aeubanks requested review of this revision.Feb 16 2022, 8:45 PM
Herald added a project: Restricted Project. · View Herald TranscriptFeb 16 2022, 8:45 PM
Herald added a subscriber: llvm-commits. · View Herald Transcript
Harbormaster completed remote builds in B150129: Diff 409479.Feb 16 2022, 8:46 PM
nikic accepted this revision.Feb 17 2022, 12:17 AM
nikic added a subscriber: nikic.

LGTM

This revision is now accepted and ready to land.Feb 17 2022, 12:17 AM
This revision was landed with ongoing or failed builds.Feb 17 2022, 8:51 AM
Closed by commit rG129af4daa7ce: [SCEVExpander][OpaquePtr] Check GEP source type when finding identical GEP (authored by aeubanks). · Explain Why
This revision was automatically updated to reflect the committed changes.
aeubanks added a commit: rG129af4daa7ce: [SCEVExpander][OpaquePtr] Check GEP source type when finding identical GEP.

Revision Contents

PathSize
llvm/
lib/
Transforms/
Utils/
4 lines
test/
Transforms/
IndVarSimplify/
3 lines

Diff 409677

llvm/lib/Transforms/Utils/ScalarEvolutionExpander.cpp

Show First 20 Lines • Show All 585 Lines • ▼ Show 20 Lines if (!AnyNonZeroIndices) {
if (IP != BlockBegin) { if (IP != BlockBegin) {
--IP; --IP;
for (; ScanLimit; --IP, --ScanLimit) { for (; ScanLimit; --IP, --ScanLimit) {
// Don't count dbg.value against the ScanLimit, to avoid perturbing the // Don't count dbg.value against the ScanLimit, to avoid perturbing the
// generated code. // generated code.
if (isa<DbgInfoIntrinsic>(IP)) if (isa<DbgInfoIntrinsic>(IP))
ScanLimit++; ScanLimit++;
if (IP->getOpcode() == Instruction::GetElementPtr && if (IP->getOpcode() == Instruction::GetElementPtr &&
IP->getOperand(0) == V && IP->getOperand(1) == Idx) IP->getOperand(0) == V && IP->getOperand(1) == Idx &&
cast<GEPOperator>(&*IP)->getSourceElementType() ==
Type::getInt8Ty(Ty->getContext()))
return &*IP; return &*IP;
if (IP == BlockBegin) break; if (IP == BlockBegin) break;
} }
} }
// Save the original insertion point so we can restore it when we're done. // Save the original insertion point so we can restore it when we're done.
SCEVInsertPointGuard Guard(Builder, this); SCEVInsertPointGuard Guard(Builder, this);
▲ Show 20 Lines • Show All 2,206 Lines • Show Last 20 Lines

llvm/test/Transforms/IndVarSimplify/opaque-ptr.ll

; NOTE: Assertions have been autogenerated by utils/update_test_checks.py ; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
; RUN: opt -passes=indvars -S < %s -opaque-pointers | FileCheck %s ; RUN: opt -passes=indvars -S < %s -opaque-pointers | FileCheck %s
declare void @c(ptr) declare void @c(ptr)
define void @test(ptr %arg) { define void @test(ptr %arg) {
; CHECK-LABEL: @test( ; CHECK-LABEL: @test(
; CHECK-NEXT: entry: ; CHECK-NEXT: entry:
; CHECK-NEXT: [[O:%.*]] = getelementptr ptr, ptr [[ARG:%.*]], i64 16 ; CHECK-NEXT: [[O:%.*]] = getelementptr ptr, ptr [[ARG:%.*]], i64 16
; CHECK-NEXT: call void @c(ptr [[O]]) ; CHECK-NEXT: call void @c(ptr [[O]])
; CHECK-NEXT: [[UGLYGEP:%.*]] = getelementptr i8, ptr [[ARG]], i64 16
; CHECK-NEXT: br label [[LOOP:%.*]] ; CHECK-NEXT: br label [[LOOP:%.*]]
; CHECK: loop: ; CHECK: loop:
; CHECK-NEXT: [[IDX:%.*]] = phi i32 [ 1, [[ENTRY:%.*]] ], [ [[INC:%.*]], [[LOOP]] ] ; CHECK-NEXT: [[IDX:%.*]] = phi i32 [ 1, [[ENTRY:%.*]] ], [ [[INC:%.*]], [[LOOP]] ]
; CHECK-NEXT: [[INC]] = add nuw nsw i32 [[IDX]], 1 ; CHECK-NEXT: [[INC]] = add nuw nsw i32 [[IDX]], 1
; CHECK-NEXT: [[C:%.*]] = icmp ne i32 [[INC]], 16 ; CHECK-NEXT: [[C:%.*]] = icmp ne i32 [[INC]], 16
; CHECK-NEXT: call void @c(ptr [[O]]) ; CHECK-NEXT: call void @c(ptr [[UGLYGEP]])
; CHECK-NEXT: br i1 [[C]], label [[LOOP]], label [[END:%.*]] ; CHECK-NEXT: br i1 [[C]], label [[LOOP]], label [[END:%.*]]
; CHECK: end: ; CHECK: end:
; CHECK-NEXT: ret void ; CHECK-NEXT: ret void
; ;
entry: entry:
%o = getelementptr ptr, ptr %arg, i64 16 %o = getelementptr ptr, ptr %arg, i64 16
call void @c(ptr %o) call void @c(ptr %o)
br label %loop br label %loop
Show All 13 Lines