[llvm] 64249f1 - [CodeExtractor] Fix extraction of a value used only by intrinsics outside of region
Ehud Katz via llvm-commits
llvm-commits at lists.llvm.org
Sat Apr 25 01:46:19 PDT 2020
Author: Ehud Katz
Date: 2020-04-25T11:44:47+03:00
New Revision: 64249f177e4644cfe3a0ba80ade274175771950c
URL: https://github.com/llvm/llvm-project/commit/64249f177e4644cfe3a0ba80ade274175771950c
DIFF: https://github.com/llvm/llvm-project/commit/64249f177e4644cfe3a0ba80ade274175771950c.diff
LOG: [CodeExtractor] Fix extraction of a value used only by intrinsics outside of region
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
Added:
llvm/test/Transforms/CodeExtractor/LoopExtractor_alloca.ll
Modified:
llvm/lib/Transforms/Utils/CodeExtractor.cpp
Removed:
################################################################################
diff --git a/llvm/lib/Transforms/Utils/CodeExtractor.cpp b/llvm/lib/Transforms/Utils/CodeExtractor.cpp
index a261040d10bc..5532c2cc5aaf 100644
--- a/llvm/lib/Transforms/Utils/CodeExtractor.cpp
+++ b/llvm/lib/Transforms/Utils/CodeExtractor.cpp
@@ -451,18 +451,24 @@ 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;
}
- 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.
if (!definedInRegion(Blocks, U))
diff --git a/llvm/test/Transforms/CodeExtractor/LoopExtractor_alloca.ll b/llvm/test/Transforms/CodeExtractor/LoopExtractor_alloca.ll
new file mode 100644
index 000000000000..33de795eb200
--- /dev/null
+++ b/llvm/test/Transforms/CodeExtractor/LoopExtractor_alloca.ll
@@ -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)
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