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Differential D108232

[GlobalOpt] Check stored once value's type before setting global initializer
ClosedPublic

Authored by aeubanks on Aug 17 2021, 12:05 PM.

Details

Reviewers
scui
rnk
efriedma
Commits
rG16890e004085: [GlobalOpt] Check stored once value's type before setting global initializer
Summary

In the provided test case, we were trying to set the global's
initializer to i32* null when the global's value type was @0.

Diff Detail

Event Timeline

aeubanks created this revision.Aug 17 2021, 12:05 PM
Herald added subscribers: ormris, jfb, hiraditya. · View Herald TranscriptAug 17 2021, 12:05 PM
aeubanks requested review of this revision.Aug 17 2021, 12:05 PM
Herald added a project: Restricted Project. · View Herald TranscriptAug 17 2021, 12:05 PM
Herald added a subscriber: llvm-commits. · View Herald Transcript
aeubanks added reviewers: scui, rnk, efriedma.Aug 17 2021, 12:06 PM

seems to be caused by D106589

aeubanks updated this revision to Diff 366976.Aug 17 2021, 12:06 PM

update

Harbormaster completed remote builds in B119957: Diff 366976.Aug 17 2021, 12:59 PM
rnk accepted this revision.Aug 17 2021, 1:35 PM

lgtm

This revision is now accepted and ready to land.Aug 17 2021, 1:35 PM
Closed by commit rG16890e004085: [GlobalOpt] Check stored once value's type before setting global initializer (authored by aeubanks). · Explain WhyAug 17 2021, 2:39 PM
This revision was automatically updated to reflect the committed changes.
aeubanks added a commit: rG16890e004085: [GlobalOpt] Check stored once value's type before setting global initializer.

Revision Contents

PathSize
llvm/
lib/
Transforms/
IPO/
3 lines
test/
Transforms/
GlobalOpt/
22 lines

Diff 367019

llvm/lib/Transforms/IPO/GlobalOpt.cpp

Show First 20 Lines • Show All 1,604 Lines • ▼ Show 20 Lines if (SRAGlobal(GV, DL))
return true; return true;
} }
if (GS.StoredType == GlobalStatus::StoredOnce && GS.StoredOnceValue) { if (GS.StoredType == GlobalStatus::StoredOnce && GS.StoredOnceValue) {
// If the initial value for the global was an undef value, and if only // If the initial value for the global was an undef value, and if only
// one other value was stored into it, we can just change the // one other value was stored into it, we can just change the
// initializer to be the stored value, then delete all stores to the // initializer to be the stored value, then delete all stores to the
// global. This allows us to mark it constant. // global. This allows us to mark it constant.
if (Constant *SOVConstant = dyn_cast<Constant>(GS.StoredOnceValue)) if (Constant *SOVConstant = dyn_cast<Constant>(GS.StoredOnceValue))
if (isa<UndefValue>(GV->getInitializer())) { if (SOVConstant->getType() == GV->getValueType() &&
isa<UndefValue>(GV->getInitializer())) {
// Change the initial value here. // Change the initial value here.
GV->setInitializer(SOVConstant); GV->setInitializer(SOVConstant);
// Clean up any obviously simplifiable users now. // Clean up any obviously simplifiable users now.
CleanupConstantGlobalUsers(GV, GV->getInitializer(), DL, GetTLI); CleanupConstantGlobalUsers(GV, GV->getInitializer(), DL, GetTLI);
if (GV->use_empty()) { if (GV->use_empty()) {
LLVM_DEBUG(dbgs() << " *** Substituting initializer allowed us to " LLVM_DEBUG(dbgs() << " *** Substituting initializer allowed us to "
▲ Show 20 Lines • Show All 1,145 Lines • Show Last 20 Lines

llvm/test/Transforms/GlobalOpt/stored-once-value-type.ll

  • This file was added.
; RUN: opt -passes=globalopt < %s -S | FileCheck %s
; Check that we don't try to set a global initializer to a value of a different type.
; In this case, we were trying to set @0's initializer to be i32* null.
%0 = type { i32* }
@0 = internal global %0* null
; CHECK: global %0 undef
define void @a() {
%1 = tail call i8* @_Znwm(i64 8)
%2 = bitcast i8* %1 to %0*
%3 = getelementptr inbounds %0, %0* %2, i64 0, i32 0
store i32* null, i32** %3, align 8
store i8* %1, i8** bitcast (%0** @0 to i8**), align 8
%4 = load i64*, i64** bitcast (%0** @0 to i64**), align 8
%5 = load atomic i64, i64* %4 acquire, align 8
ret void
}
declare i8* @_Znwm(i64)