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[MemLoc] Fix a bug causing any use of invariant.end to crash in LICM

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The fix is fairly simple, but is says something unpleasant about the usage and testing of invariant.start/end scopes that this went undetected.  To put this in perspective, *any* invariant.end in a loop flowing through LICM crashed.  I haven't bothered to figure out just how far back this goes, but it's not caused by any of the recent changes.  We're probably talking months if not years.  

llvm-svn: 339936
This commit is contained in:
Philip Reames 2018-08-16 20:48:55 +00:00
parent 4e039107e1
commit 966e21bd41
2 changed files with 5 additions and 3 deletions
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4
lib/Analysis/MemoryLocation.cpp
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@ -137,6 +137,10 @@ MemoryLocation MemoryLocation::getForArgument(ImmutableCallSite CS,
Arg, cast<ConstantInt>(II->getArgOperand(0))->getZExtValue(), AATags);
case Intrinsic::invariant_end:
// The first argument to an invariant.end is a "descriptor" type (e.g. a
// pointer to a empty struct) which is never actually dereferenced.
if (ArgIdx == 0)
return MemoryLocation(Arg, 0, AATags);
assert(ArgIdx == 2 && "Invalid argument index");
return MemoryLocation(
Arg, cast<ConstantInt>(II->getArgOperand(1))->getZExtValue(), AATags);

4
test/Transforms/LICM/invariant.start.ll
View File

@ -101,9 +101,7 @@ loop:
store i32 0, i32* %ptr
%scope = call {}* @llvm.invariant.start.p0i32(i64 4, i32* %ptr)
%val = load i32, i32* %ptr
;; NOTE: despite being correct syntax, uncommenting this line causes
;; a crash in the optimizer. FIXME
;; call void @llvm.invariant.end.p0i32({}* %scope, i64 4, i32* %ptr)
call void @llvm.invariant.end.p0i32({}* %scope, i64 4, i32* %ptr)
%x.inc = add i32 %x, %val
br label %loop
}