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[CodeExtractor] Fix extraction of a value used only by intrinsics outside of region

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We should only skip `lifetime` and `dbg` intrinsics when searching for users.
Other intrinsics are legit users that can't be ignored.

Without this fix, the testcase would result in an invalid IR. `memcpy`
will have a reference to the, now, external value (local to the
extracted loop function).

Fix PR42194

Differential Revision: https://reviews.llvm.org/D78749
This commit is contained in:
Ehud Katz 2020-04-25 11:44:47 +03:00
parent 5f4363a734
commit a45c842965
2 changed files with 66 additions and 2 deletions
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8
lib/Transforms/Utils/CodeExtractor.cpp
View File

@ -451,17 +451,23 @@ CodeExtractor::getLifetimeMarkers(const CodeExtractorAnalysisCache &CEAC,
for (User *U : Addr->users()) {
IntrinsicInst *IntrInst = dyn_cast<IntrinsicInst>(U);
if (IntrInst) {
// We don't model addresses with multiple start/end markers, but the
// markers do not need to be in the region.
if (IntrInst->getIntrinsicID() == Intrinsic::lifetime_start) {
// Do not handle the case where Addr has multiple start markers.
if (Info.LifeStart)
return {};
Info.LifeStart = IntrInst;
continue;
}
if (IntrInst->getIntrinsicID() == Intrinsic::lifetime_end) {
if (Info.LifeEnd)
return {};
Info.LifeEnd = IntrInst;
continue;
}
// At this point, permit debug uses outside of the region.
// This is fixed in a later call to fixupDebugInfoPostExtraction().
if (isa<DbgInfoIntrinsic>(IntrInst))
continue;
}
// Find untracked uses of the address, bail.

58
test/Transforms/CodeExtractor/LoopExtractor_alloca.ll Normal file
View File

@ -0,0 +1,58 @@
; RUN: opt -debugify -loop-extract -S < %s | FileCheck %s
; This tests 2 cases:
; 1. loop1 should be extracted into a function, without extracting %v1 alloca.
; 2. loop2 should be extracted into a function, with the %v2 alloca.
;
; This used to produce an invalid IR, where `memcpy` will have a reference to
; the, now, external value (local to the extracted loop function).
; CHECK-LABEL: define void @test()
; CHECK-NEXT: entry:
; CHECK-NEXT: %v1 = alloca i32
; CHECK-NEXT: call void @llvm.dbg.value(metadata i32* %v1
; CHECK-NEXT: %p1 = bitcast i32* %v1 to i8*
; CHECK-NEXT: call void @llvm.dbg.value(metadata i8* %p1,
; CHECK-NEXT: call void @llvm.memcpy.p0i8.p0i8.i64(i8* align 4 undef, i8* %p1, i64 4, i1 true)
; CHECK-LABEL: define internal void @test.loop2()
; CHECK-NEXT: newFuncRoot:
; CHECK-NEXT: %v2 = alloca i32
; CHECK-NEXT: %p2 = bitcast i32* %v2 to i8*
; CHECK-LABEL: define internal void @test.loop1(i8* %p1)
; CHECK-NEXT: newFuncRoot:
; CHECK-NEXT: br
define void @test() {
entry:
%v1 = alloca i32, align 4
%v2 = alloca i32, align 4
%p1 = bitcast i32* %v1 to i8*
%p2 = bitcast i32* %v2 to i8*
call void @llvm.memcpy.p0i8.p0i8.i64(i8* align 4 undef, i8* %p1, i64 4, i1 true)
br label %loop1
loop1:
call void @llvm.lifetime.start.p0i8(i64 4, i8* %p1)
%r1 = call i32 @foo(i8* %p1)
call void @llvm.lifetime.end.p0i8(i64 4, i8* %p1)
%cmp1 = icmp ne i32 %r1, 0
br i1 %cmp1, label %loop1, label %loop2
loop2:
call void @llvm.lifetime.start.p0i8(i64 4, i8* %p2)
%r2 = call i32 @foo(i8* %p2)
call void @llvm.lifetime.end.p0i8(i64 4, i8* %p2)
%cmp2 = icmp ne i32 %r2, 0
br i1 %cmp2, label %loop2, label %exit
exit:
ret void
}
declare i32 @foo(i8*)
declare void @llvm.lifetime.start.p0i8(i64 immarg, i8* nocapture)
declare void @llvm.lifetime.end.p0i8(i64 immarg, i8* nocapture)
declare void @llvm.memcpy.p0i8.p0i8.i64(i8* noalias nocapture writeonly, i8* noalias nocapture readonly, i64, i1 immarg)