search for: isallocaptrvaluenonzero

...ain targets. For example, amdgcn---amdgiz target has alloca in address space 5, and its alloca always has non-zero value. This assumption causes some optimizations disabled for amdgcn---amdgiz target. After discussions at https://reviews.llvm.org/D40670, I propose to introduce TargetTransformInfo::isAllocaPtrValueNonZero for representing whether alloca instruction always has non-zero value, and add a TargetTransformInfo argument to ValueTracking functions e.g. isKnownNonZero(). As a result, passes using ValueTracking will require TargetTransformInfo. Comments are welcome. Thanks. Sam -------------- next part --...

...-A5, which means alloca is in address space 5. How about adding a letter z to -A5 to indicate alloca may have zero value? i.e. -A5 means alloca is in address space 5 and always has non-zero value, -A5z means alloca is in address space 5 and may have zero value. Then we can add function DataLayout::isAllocaPtrValueNonZero() to check whether alloca always has non-zero value. Sam From: Hal Finkel [mailto:hfinkel at anl.gov] Sent: Thursday, December 14, 2017 4:06 PM To: Liu, Yaxun (Sam) <Yaxun.Liu at amd.com>; llvm-dev <llvm-dev at lists.llvm.org> Subject: Re: [llvm-dev] [RFC] Add TargetTransformInfo::isA...

> On Dec 14, 2017, at 20:28, Hal Finkel via llvm-dev <llvm-dev at lists.llvm.org> wrote: > > Would that address your use case? Or can you have null dereferenceable pointers in that address space, just not ones from alloca? I would like to clarify what “null” means exactly. One related thing I would like in the future is for the DataLayout to specify what numeric value is the