Commit Graph

3 Commits

Author SHA1 Message Date
Dorit Nuzman bf2c15b5dc Second attempt at r285517.
llvm-svn: 285568
2016-10-31 13:17:31 +00:00
Dorit Nuzman 06903d16af Revert r285517 due to build failures.
llvm-svn: 285518
2016-10-30 14:34:57 +00:00
Dorit Nuzman 3c1c658f24 [LoopVectorize] Make interleaved-accesses analysis less conservative about
possible pointer-wrap-around concerns, in some cases.

Before this patch, collectConstStridedAccesses (part of interleaved-accesses
analysis) called getPtrStride with [Assume=false, ShouldCheckWrap=true] when
examining all candidate pointers. This is too conservative. Instead, this
patch makes collectConstStridedAccesses use an optimistic approach, calling
getPtrStride with [Assume=true, ShouldCheckWrap=false], and then, once the
candidate interleave groups have been formed, revisits the pointer-wrapping
analysis but only where it matters: namely, in groups that have gaps, and where
the gaps are not at the very end of the group (in which case the loop is
peeled). This second time getPtrStride is called with [Assume=false,
ShouldCheckWrap=true], but this could further be improved to using Assume=true,
once we also add the logic to track that we are not going to meet the scev
runtime checks threshold.

Differential Revision: https://reviews.llvm.org/D25276

llvm-svn: 285517
2016-10-30 12:23:26 +00:00