[llvm-commits] [llvm] r47252 - /llvm/trunk/lib/Analysis/BasicAliasAnalysis.cpp
Bill Wendling
isanbard at gmail.com
Sun Feb 17 22:27:54 PST 2008
What are the bugs?
-bw
On Feb 17, 2008, at 6:31 PM, Owen Anderson wrote:
> Author: resistor
> Date: Sun Feb 17 20:31:23 2008
> New Revision: 47252
>
> URL: http://llvm.org/viewvc/llvm-project?rev=47252&view=rev
> Log:
> Fix bugs that Chris noticed in my last patch.
>
> Modified:
> llvm/trunk/lib/Analysis/BasicAliasAnalysis.cpp
>
> Modified: llvm/trunk/lib/Analysis/BasicAliasAnalysis.cpp
> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Analysis/
> BasicAliasAnalysis.cpp?rev=47252&r1=47251&r2=47252&view=diff
>
> ======================================================================
> ========
> --- llvm/trunk/lib/Analysis/BasicAliasAnalysis.cpp (original)
> +++ llvm/trunk/lib/Analysis/BasicAliasAnalysis.cpp Sun Feb 17
> 20:31:23 2008
> @@ -250,22 +250,30 @@
> const Value *Object = getUnderlyingObject(P);
> // Allocations and byval arguments are "new" objects.
> if (Object &&
> - (isa<AllocationInst>(Object) ||
> - (isa<Argument>(Object) &&
> - (cast<Argument>(Object)-
> >hasByValAttr() ||
> - cast<Argument>(Object)-
> >hasNoAliasAttr())))) {
> + (isa<AllocationInst>(Object) || isa<Argument>(Object))) {
> // Okay, the pointer is to a stack allocated (or effectively
> so, for
> // for noalias parameters) object. If we can prove that
> // the pointer never "escapes", then we know the call cannot
> clobber it,
> // because it simply can't get its address.
> - if (!AddressMightEscape(Object))
> - return NoModRef;
> + if (isa<AllocationInst>(Object) ||
> + cast<Argument>(Object)->hasByValAttr() ||
> + cast<Argument>(Object)->hasNoAliasAttr())
> + if (!AddressMightEscape(Object)) {
> + for (CallSite::arg_iterator CI = CS.arg_begin(), CE =
> CS.arg_end();
> + CI != CE; ++CI)
> + if (getUnderlyingObject(CI->get()) == P)
> + return AliasAnalysis::getModRefInfo(CS, P, Size);
> +
> + return NoModRef;
> + }
>
> // If this is a tail call and P points to a stack location,
> we know that
> // the tail call cannot access or modify the local stack.
> - if (CallInst *CI = dyn_cast<CallInst>(CS.getInstruction()))
> - if (CI->isTailCall() && !isa<MallocInst>(Object))
> - return NoModRef;
> + if (isa<AllocationInst>(Object) ||
> + cast<Argument>(Object)->hasByValAttr())
> + if (CallInst *CI = dyn_cast<CallInst>(CS.getInstruction()))
> + if (CI->isTailCall() && !isa<MallocInst>(Object))
> + return NoModRef;
> }
> }
>
>
>
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