[SimplifyCFG] Mark missed Changed to true.

Summary:
DominatorTree is invalid after SimplifyCFG because of a missed `Changed = true` when simplifying a branch condition and removing an edge.
Resolves PR42272.

Reviewers: zhizhouy, manojgupta

Subscribers: jlebar, sanjoy.google, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D65490

llvm-svn: 367596
This commit is contained in:
Alina Sbirlea 2019-08-01 18:37:34 +00:00
parent 52f12f63f4
commit 3af2a69575
2 changed files with 91 additions and 0 deletions

View File

@ -4189,6 +4189,7 @@ bool SimplifyCFGOpt::SimplifyUnreachable(UnreachableInst *UI) {
Builder.CreateAssumption(Builder.CreateNot(Cond));
Builder.CreateBr(BI->getSuccessor(1));
EraseTerminatorAndDCECond(BI);
Changed = true;
} else if (BI->getSuccessor(1) == BB) {
Builder.CreateAssumption(Cond);
Builder.CreateBr(BI->getSuccessor(0));

View File

@ -0,0 +1,90 @@
; RUN: opt -aa-pipeline=default -passes="default<O2>" -disable-output %s
; REQUIRES: asserts
; PR42272
target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
target triple = "x86_64-unknown-linux-gnu"
@b = external global i32, align 4
@f = external global i32, align 4
@g = external global i32, align 4
define i32* @a(i32 %h) #0 {
entry:
%h.addr = alloca i32, align 4
store i32 %h, i32* %h.addr, align 4
%tmp0 = load i32, i32* %h.addr, align 4
switch i32 %tmp0, label %sw.default [
i32 4, label %sw.bb
i32 3, label %sw.bb1
i32 2, label %sw.bb3
]
sw.bb: ; preds = %entry
%call = call i32 (...) @c()
unreachable
sw.bb1: ; preds = %entry
%call2 = call i32 (...) @c()
unreachable
sw.bb3: ; preds = %entry
%call4 = call i32 (...) @c()
%conv = sext i32 %call4 to i64
%tmp1 = inttoptr i64 %conv to i32*
ret i32* %tmp1
sw.default: ; preds = %entry
unreachable
}
define i32 @m() #1 {
entry:
%call = call i32 @j()
%call1 = call i32 @j()
ret i32 undef
}
define internal i32 @j() #0 {
entry:
%i = alloca i32, align 4
store i32 0, i32* %i, align 4
br label %for.cond
for.cond: ; preds = %for.body, %entry
%tmp0 = load i32, i32* %i, align 4
%tmp1 = load i32, i32* @f, align 4
%cmp = icmp ult i32 %tmp0, %tmp1
br i1 %cmp, label %for.body, label %for.cond.cleanup
for.cond.cleanup: ; preds = %for.cond
%tmp2 = load i32, i32* @f, align 4
%call3 = call i32* @a(i32 %tmp2)
ret i32 undef
for.body: ; preds = %for.cond
%call = call i32 (...) @c()
%call1 = call i32 (...) @c()
%call2 = call i32 (...) @c()
%tmp3 = load i32, i32* @b, align 4
%tmp4 = load i32, i32* @g, align 4
%sub = sub nsw i32 %tmp4, %tmp3
store i32 %sub, i32* @g, align 4
%tmp5 = load i32, i32* %i, align 4
%inc = add i32 %tmp5, 1
store i32 %inc, i32* %i, align 4
br label %for.cond
}
declare i32 @c(...) #0
; Function Attrs: argmemonly nounwind
declare void @llvm.lifetime.start.p0i8(i64 immarg, i8* nocapture) #2
; Function Attrs: argmemonly nounwind
declare void @llvm.lifetime.end.p0i8(i64 immarg, i8* nocapture) #2
attributes #0 = { "use-soft-float"="false" }
attributes #1 = { "target-cpu"="x86-64" }
attributes #2 = { argmemonly nounwind }