search for: findaliassetforunknowninst

...alias sets in the AliasSetTracker::addUnknown, have the following form: call void @llvm.memset.p0i8.i64(i8* %scevgep..., i8 0, i64 256, i32 8, i1 false) Furthermore, in this case, there aren’t any unknown instructions, which are added by AliasSetTracker::addUnknown to alias sets that are found by findAliasSetForUnknownInst. That’s why I would like to check objects of MemoryLocation class that are created for ‘llvm.memset.*‘ intrinsics. If I’m not mistaken, objects of MemoryLocation class are involved in alias analysis and, in particular, in work of findAliasSetForUnknownInst. Thank you for the attention! --...

Thank you for the idea! Could you please explain it? If I’m not mistaken, you advise to insert the unknown insts of an every AS from AliasSetTracker::add(const AliasSetTracker &AST) into a smallptrset and consequently append it to merged alias sets from AliasSetTracker::findAliasSetForUnknownInst. I think that Philip proposed something similar to your approach in https://llvm.org/bugs/show_bug.cgi?id=23077. 2016-01-24 22:44 GMT+05:00 Daniel Berlin <dberlin at dberlin.org>: > It sounds like UnknownInsts should really be a SmallSet, SmallPtrSet, or > DenseSet (if you can't do...

2015-12-11 23:44 GMT+05:00 Hal Finkel <hfinkel at anl.gov>: > Hi Roman, > > The MemoryLocation objects are involved in findAliasSetForUnknownInst, but none are created there for the memset intrinsic. MemoryLocation objects are only involved for the regular memory accesses being compared to the unknown instruction. See AliasSet::aliasesUnknownInst in lib/Analysis/AliasSetTracker.cpp. > > We do know how to create MemoryLocation objects f...

...acker merging AliasSet's when meet UnknownInst. When adding new pointer it looks for existing AliasSet's aliased with new pointer. And merging them together. It is ok for pointers: if %A mayalias %B and %B mayalias %C then %A mayalias %C. But the same logic when adding callsite is wrong ( findAliasSetForUnknownInst). Callsite may be known to readonly access one pointer and change the content of other pointer. Why to merge together two noalias pointers if they have some mod/ref relationships with common callsite? If modrefinfo(%A, %call1) == REF and modrefinfo(%B, %call1) == MOD it doesn't mean %A may/mu...

...i know where to concetrate? > > If I’m not > mistaken, you advise to insert the unknown insts of an every AS from > AliasSetTracker::add(const AliasSetTracker &AST) into a smallptrset > and consequently append it to merged alias sets from > AliasSetTracker::findAliasSetForUnknownInst. > > > Well, no. This is not the only place duplication can occur, because > the merging of unknownInsts can occur through findAliasSetForPointer > as well, if that AS has unknown instructions. > > > See below. > > I think that Philip > proposed something...

Dear llvm contributors, Could you please advise me how to skip checks, which are performed in AliasSet::aliasesUnknownInst, of unknown instructions from different alias sets of an alias set tracker that is a parameter of ‘AliasSetTracker::add(const AliasSetTracker &AST)’? If this wasn’t available at the moment and someone could review me, I would try to implement it. A temporary patch can be