search for: pr30615

> On 10/18/2016 5:06 AM, Nuno Lopes via llvm-dev wrote: >> Another use is, for example, to implement bit-fields: >> a.x = 2 >> becomes: >> %v = load %a >> %v2 = freeze %v ; %v could be uninitialized data (poison) >> %v3 = ... bitmasking... >> store %a, %v3 > > It seems like you're saying that an integer load which touches any >

...valent) 4) Fix InstCombine, Loop unswitching, etc to use freeze 5) Replace references to undef in the code with either poison or 'freeze poison' 7) Kill undef 8) Investigate any perf regressions 9) Run John's LLVM IR fuzzer with Alive to find leftover bugs Regarding perf, at least PR30615 needs fixing to enable efficient load widening at IR level (which seems it's still undecided whether GVN will continue doing it or not). Discussion on select ==================== Select is a tricky instruction to define semantics for. There are multiple views of select's purpose that ar...

...valent) 4) Fix InstCombine, Loop unswitching, etc to use freeze 5) Replace references to undef in the code with either poison or 'freeze poison' 7) Kill undef 8) Investigate any perf regressions 9) Run John's LLVM IR fuzzer with Alive to find leftover bugs Regarding perf, at least PR30615 needs fixing to enable efficient load widening at IR level (which seems it's still undecided whether GVN will continue doing it or not). Discussion on select ==================== Select is a tricky instruction to define semantics for. There are multiple views of select's purpose that ar...