Seriously strengthen the guarantee offered by noalias on a function's return

value. It must now be as if the pointer were allocated and has not escaped to
the caller. Thanks to Dan Gohman for pointing out the error in the original
and helping devise this definition.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@59940 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Nick Lewycky
2008-11-24 05:00:44 +00:00
parent 02ff308aa1
commit b2b32fd3fe
2 changed files with 6 additions and 6 deletions

View File

@ -383,9 +383,9 @@ BasicAliasAnalysis::alias(const Value *V1, unsigned V1Size,
if (isIdentifiedObject(O1) && isIdentifiedObject(O2))
return NoAlias;
// Local allocations can't alias with arguments or noalias functions.
if ((isa<AllocationInst>(O1) && (isa<Argument>(O2) || isNoAliasCall(O2))) ||
(isa<AllocationInst>(O2) && (isa<Argument>(O1) || isNoAliasCall(O1))))
// Arguments can't alias with local allocations or noalias calls.
if ((isa<Argument>(O1) && (isa<AllocationInst>(O2) || isNoAliasCall(O2))) ||
(isa<Argument>(O2) && (isa<AllocationInst>(O1) || isNoAliasCall(O1))))
return NoAlias;
// Most objects can't alias null.