This is an archive of the discontinued LLVM Phabricator instance.

Differential D137029

[test][InstCombine] Add a test case for volatile memcpy forwarding in InstCombine, which is currently optimized incorrectly.
ClosedPublic

Authored by pcwalton on Oct 29 2022, 5:15 PM.

Details

Reviewers
nikic
Commits
rG8357ff6f3d6d: [test][InstCombine] Add a test case for volatile memcpy forwarding in…
Summary

D136822 demonstrated that we currently delete volatile memcpys in InstCombine,
which we shouldn't do. This commit adds a test for this. A forthcoming commit
will fix it.

Diff Detail

Event Timeline

pcwalton created this revision.Oct 29 2022, 5:15 PM
Herald added a project: Restricted Project. · View Herald TranscriptOct 29 2022, 5:15 PM
pcwalton requested review of this revision.Oct 29 2022, 5:15 PM
Herald added a project: Restricted Project. · View Herald TranscriptOct 29 2022, 5:15 PM
Herald added a subscriber: llvm-commits. · View Herald Transcript
pcwalton added a reviewer: nikic.Oct 29 2022, 5:16 PM

Wasn't sure if this needed review, but I wanted to be safe.

Harbormaster completed remote builds in B195122: Diff 471795.Oct 29 2022, 6:04 PM
nikic accepted this revision.Oct 30 2022, 12:52 AM

LGTM

Wasn't sure if this needed review, but I wanted to be safe.

Test additions generally don't require review.

This revision is now accepted and ready to land.Oct 30 2022, 12:52 AM
nikic mentioned this in D137031: [InstCombine] Avoid deleting volatile memcpys..Oct 30 2022, 12:54 AM
Closed by commit rG8357ff6f3d6d: [test][InstCombine] Add a test case for volatile memcpy forwarding in… (authored by pcwalton). · Explain WhyOct 30 2022, 2:38 AM
This revision was automatically updated to reflect the committed changes.
pcwalton added a commit: rG8357ff6f3d6d: [test][InstCombine] Add a test case for volatile memcpy forwarding in….

Revision Contents

PathSize
llvm/
test/
Transforms/
InstCombine/
12 lines

Diff 471823

llvm/test/Transforms/InstCombine/memcpy-from-global.ll

Show First 20 Lines • Show All 360 Lines • ▼ Show 20 Lines
; CHECK-NEXT: ret void ; CHECK-NEXT: ret void
; ;
%alloca = alloca %T, align 8 %alloca = alloca %T, align 8
call void @llvm.memcpy.p0.p0.i64(ptr %alloca, ptr %arg, i64 124, i1 false) call void @llvm.memcpy.p0.p0.i64(ptr %alloca, ptr %arg, i64 124, i1 false)
call void @bar(ptr %alloca) readonly call void @bar(ptr %alloca) readonly
ret void ret void
} }
; FIXME: Test that we incorrectly elide a volatile memcpy.
define void @volatile_memcpy() {
; CHECK-LABEL: @volatile_memcpy(
; CHECK-NEXT: call void @bar(ptr nonnull @H) #[[ATTR3]]
; CHECK-NEXT: ret void
;
%A = alloca %U, align 16
call void @llvm.memcpy.p0.p0.i64(ptr align 4 %A, ptr align 4 @H, i64 20, i1 true)
call void @bar(ptr %A) readonly
ret void
}
attributes #0 = { null_pointer_is_valid } attributes #0 = { null_pointer_is_valid }