search for: d10368

...>> %x = phi [ %incptr, ... ] [ %var, ... ] >> %incptr = getelementptr %x, 1 >> >> We will basically always return MayAlias for %x and any other value >> because aliasPHI recurses on the first value and gives up. > > Patch now posted as http://reviews.llvm.org/D10368 > > Tobias > > -- > Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, a > Linux Foundation Collaborative Project. > _______________________________________________ > LLVM Developers mailing list > LLVMdev at cs.uiuc.edu http://llvm.cs.uiuc.edu &gt...

Hi all, I came across the following limitation in our BasicAliasAnalysis. This happens with the following IR pattern: %x = phi [ %incptr, ... ] [ %var, ... ] %incptr = getelementptr %x, 1 We will basically always return MayAlias for %x and any other value because aliasPHI recurses on the first value and gives up. There are, however, many cases where this is too conservative. Take the

> Not a huge change here although the numbers tend to be more on the side > of a slowdown. This is interesting - you'd think that better alias > analysis shouldn't have that effect. Any idea what could be causing > this? LLVM's alias analysis is good but not amazing. If you improve it significantly (as you appear to have :P), you give the compiler more freedom to do

...;> >> %incptr = getelementptr %x, 1 >> >> >> >> We will basically always return MayAlias for %x and any other value >> >> because aliasPHI recurses on the first value and gives up. >> > >> > Patch now posted as http://reviews.llvm.org/D10368 >> > >> > Tobias >> > >> > -- >> > Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, a >> > Linux Foundation Collaborative Project. >> > _______________________________________________ >> > LLVM Developers mail...