Hi,
The following patch aims to address bug #20074, and similar ones. The problem is that accesses to elements in constant-sized char arrays end up annotated with TBAA tags that have base as "omnipotent char", so they'll alias with pointers other than pointers to char. This prevents some optimizations, such as removing redundant loads in bug #20074. Or in the case of the attached test cases, it prevents hoisting of loads from loops. The fix is to change the base type to that of "char" if we know we are dealing with constant sized char arrays. In effect, this mimics the behaviour of aliasing generated for other types of arrays (e.g. the base type is not the "omnipotent char", but there is a path that eventually leads to it). I didn't attempt to address VLAs. Can someone please review? Thanks, Sanjin
tbaa-char-arrays.patch
Description: Binary data
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