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LoopIdiom: Give up when the loop is not in canonical form.

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We rely on it when doing the transforms. This can happen when there is an
indirectbr in  the loop.

Fixes PR13892.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@164383 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Benjamin Kramer 2012-09-21 17:27:23 +00:00
parent e5e674ba11
commit 28aff84ceb
2 changed files with 39 additions and 0 deletions
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5
lib/Transforms/Scalar/LoopIdiomRecognize.cpp
View File

@ -175,6 +175,11 @@ static void deleteIfDeadInstruction(Value *V, ScalarEvolution &SE,
bool LoopIdiomRecognize::runOnLoop(Loop *L, LPPassManager &LPM) {
CurLoop = L;
// If the loop could not be converted to canonical form, it must have an
// indirectbr in it, just give up.
if (!L->getLoopPreheader())
return false;
// Disable loop idiom recognition if the function's name is a common idiom.
StringRef Name = L->getHeader()->getParent()->getName();
if (Name == "memset" || Name == "memcpy")

34
test/Transforms/LoopIdiom/non-canonical-loop.ll Normal file
View File

@ -0,0 +1,34 @@
; RUN: opt -S -loop-idiom < %s
; Don't crash
; PR13892
target datalayout = "e-p:64:64:64-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:64:64-f32:32:32-f64:64:64-v64:64:64-v128:128:128-a0:0:64-s0:64:64-f80:128:128-n8:16:32:64-S128"
target triple = "x86_64-unknown-linux-gnu"
define void @test(i32* %currMB) nounwind uwtable {
entry:
br i1 undef, label %start.exit, label %if.then.i
if.then.i: ; preds = %entry
unreachable
start.exit: ; preds = %entry
indirectbr i8* undef, [label %0, label %for.bodyprime]
; <label>:0 ; preds = %start.exit
unreachable
for.bodyprime: ; preds = %for.bodyprime, %start.exit
%i.057375 = phi i32 [ 0, %start.exit ], [ %1, %for.bodyprime ]
%arrayidx8prime = getelementptr inbounds i32* %currMB, i32 %i.057375
store i32 0, i32* %arrayidx8prime, align 4
%1 = add i32 %i.057375, 1
%cmp5prime = icmp slt i32 %1, 4
br i1 %cmp5prime, label %for.bodyprime, label %for.endprime
for.endprime: ; preds = %for.bodyprime
br label %for.body23prime
for.body23prime: ; preds = %for.body23prime, %for.endprime
br label %for.body23prime
}