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[LoopRotate] processLoop should return true even if it just simplified the loop latch without making any other changes

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Simplifying a loop latch changes the IR and we need to make sure the pass manager knows to invalidate analysis passes if that happened.

PR35210 discovered a case where we failed to invalidate the post dominator tree after this simplification because we no changes other than simplifying the loop latch.

Fixes PR35210.

Differential Revision: https://reviews.llvm.org/D40035

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@318237 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Craig Topper 2017-11-15 00:22:42 +00:00
parent eace9e3d8d
commit 7e9abd2530
2 changed files with 71 additions and 1 deletions
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2
lib/Transforms/Scalar/LoopRotation.cpp
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@ -634,7 +634,7 @@ bool LoopRotate::processLoop(Loop *L) {
if ((MadeChange || SimplifiedLatch) && LoopMD)
L->setLoopID(LoopMD);
return MadeChange;
return MadeChange || SimplifiedLatch;
}
LoopRotatePass::LoopRotatePass(bool EnableHeaderDuplication)

70
test/Transforms/LoopRotate/pr35210.ll Normal file
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@ -0,0 +1,70 @@
;RUN: opt %s -passes='adce,loop(rotate),adce' -S -debug-pass-manager -debug-only=loop-rotate 2>&1 | FileCheck %s
; This test is to make sure we invalidate the post dominator pass after loop rotate simplifies the loop latch.
; The adce passes are here to make sure post dominator analysis is required.
; CHECK: Starting llvm::Function pass manager run.
; CHECK-NEXT: Running pass: ADCEPass on f
; CHECK-NEXT: Running analysis: DominatorTreeAnalysis on f
; CHECK-NEXT: Running analysis: PostDominatorTreeAnalysis on f
; CHECK-NEXT: Running pass: FunctionToLoopPassAdaptor{{.*}} on f
; CHECK-NEXT: Running analysis: LoopAnalysis on f
; CHECK-NEXT: Running analysis: AssumptionAnalysis on f
; CHECK-NEXT: Running analysis: AAManager on f
; CHECK-NEXT: Running analysis: TargetLibraryAnalysis on f
; CHECK-NEXT: Running analysis: ScalarEvolutionAnalysis on f
; CHECK-NEXT: Running analysis: TargetIRAnalysis on f
; CHECK-NEXT: Running analysis: InnerAnalysisManagerProxy{{.*}} on f
; CHECK-NEXT: Starting Loop pass manager run.
; CHECK-NEXT: Running pass: LoopRotatePass on Loop at depth 1 containing: %bb<header><exiting>,%bb4<latch>
; CHECK-NEXT: Folding loop latch bb4 into bb
; CHECK-NEXT: Invalidating all non-preserved analyses for: bb
; CHECK-NEXT: Finished Loop pass manager run.
; CHECK-NEXT: Invalidating all non-preserved analyses for: f
; CHECK-NEXT: Invalidating analysis: PostDominatorTreeAnalysis on f
; CHECK-NEXT: Running pass: ADCEPass on f
; CHECK-NEXT: Running analysis: PostDominatorTreeAnalysis on f
; CHECK-NEXT: Finished llvm::Function pass manager run.
; CHECK-LABEL: define i8 @f() {
; CHECK-NEXT : entry:
; CHECK-NEXT : br label %bb
; CHECK-NEXT :
; CHECK-NEXT : bb: ; preds = %bb, %entry
; CHECK-NEXT : %mode.0 = phi i8 [ 0, %entry ], [ %indvar.next, %bb ]
; CHECK-NEXT : %tmp5 = icmp eq i8 %mode.0, 1
; CHECK-NEXT : %indvar.next = add i8 %mode.0, 1
; CHECK-NEXT : br i1 %tmp5, label %bb5, label %bb
; CHECK-NEXT :
; CHECK-NEXT : bb5: ; preds = %bb
; CHECK-NEXT : tail call void @raise_exception() #0
; CHECK-NEXT : unreachable
; CHECK-NEXT : }
; CHECK-NEXT :
; CHECK-NEXT : ; Function Attrs: noreturn
; CHECK-NEXT : declare void @raise_exception() #0
; CHECK-NEXT :
; CHECK-NEXT : attributes #0 = { noreturn }
define i8 @f() {
entry:
br label %bb
bb: ; preds = %bb4, %entry
%mode.0 = phi i8 [ 0, %entry ], [ %indvar.next, %bb4 ]
%tmp5 = icmp eq i8 %mode.0, 1
br i1 %tmp5, label %bb5, label %bb4
bb4: ; preds = %bb2
%indvar.next = add i8 %mode.0, 1
br label %bb
bb5: ; preds = %bb2
tail call void @raise_exception() #0
unreachable
}
; Function Attrs: noreturn
declare void @raise_exception() #0
attributes #0 = { noreturn }