Skip to content

[MachineLoopInfo] Fix getLoopID to handle multi latches. #106195

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Merged
merged 2 commits into from
Aug 29, 2024
Merged

[MachineLoopInfo] Fix getLoopID to handle multi latches. #106195

Show file tree
Hide file tree
Changes from all commits
Commits
Show all changes
2 commits
Select commit Hold shift + click to select a range
b52dc77
[MachineLoopInfo] Fix getLoopID to handle multi latches.
FreddyLeaf Aug 21, 2024
f58d536
address comments.
FreddyLeaf Aug 28, 2024
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
6 changes: 6 additions & 0 deletions llvm/lib/CodeGen/CodeGenPrepare.cpp
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -1183,6 +1183,12 @@ void CodeGenPrepare::eliminateMostlyEmptyBlock(BasicBlock *BB) {
}
}

// Preserve loop Metadata.
if (BI->hasMetadata(LLVMContext::MD_loop)) {
for (auto *Pred : predecessors(BB))
Pred->getTerminator()->copyMetadata(*BI, LLVMContext::MD_loop);
}

// The PHIs are now updated, change everything that refers to BB to use
// DestBB and remove BB.
BB->replaceAllUsesWith(DestBB);
Expand Down
2 changes: 1 addition & 1 deletion llvm/lib/CodeGen/MachineLoopInfo.cpp
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -212,7 +212,7 @@ MDNode *MachineLoop::getLoopID() const {
}
}
if (!MD)
return nullptr;
continue;
if (!LoopID)
LoopID = MD;
else if (MD != LoopID)
Expand Down
37 changes: 34 additions & 3 deletions llvm/test/CodeGen/X86/code-align-loops.ll
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -96,8 +96,8 @@ for.body5: ; preds = %for.body, %for.body
br i1 %exitcond16.not, label %for.cond.cleanup4, label %for.body5, !llvm.loop !2
}

; test3 is to check if .p2align can be correctly set on loops with multi latches.
; The test IR is generated from below simple C file:
; test3 and test4 is to check if .p2align can be correctly set on loops with
; multi latches. The IR is generated from below simple C file:
; $ clang -O0 -S -emit-llvm loop.c
; $ cat loop.c
; int test3() {
Expand All @@ -111,7 +111,7 @@ for.body5: ; preds = %for.body, %for.body
; }
; }
; CHECK-LABEL: test3_multilatch:
; ALIGN: .p2align 4, 0x90
; ALIGN: .p2align 6, 0x90
; ALIGN-NEXT: .LBB2_1: # %while.cond
define dso_local i32 @test3_multilatch() #0 {
entry:
Expand Down Expand Up @@ -146,6 +146,37 @@ while.end: ; preds = %while.cond
ret i32 %3
}

; CHECK-LABEL: test4_multilatch:
; ALIGN: .p2align 6, 0x90
; ALIGN-NEXT: .LBB3_4: # %bb4
define void @test4_multilatch(i32 %a, i32 %b, i32 %c, i32 %d) nounwind {
entry:
br label %bb1

bb1: ; preds = %bb2, %bb4, %entry
call void @bar()
%cmp3 = icmp sgt i32 %c, 10
br i1 %cmp3, label %bb3, label %bb4

bb2: ; preds = %bb3
call void @bar()
%cmp1 = icmp sgt i32 %a, 11
br i1 %cmp1, label %bb1, label %exit, !llvm.loop !0

bb3: ; preds = %bb1
call void @bar()
%cmp2 = icmp sgt i32 %b, 12
br i1 %cmp2, label %bb2, label %exit

bb4: ; preds = %bb1
call void @bar()
%cmp4 = icmp sgt i32 %d, 14
br i1 %cmp4, label %bb1, label %exit

exit: ; preds = %bb2, %bb3, %bb4
ret void
}

declare void @bar()
declare void @var()

Expand Down
Loading