search for: 175e37f5

In include/llvm/IR/Intrinsics.td there is code to mark sqrt and several other math intrinsics as "ReadOnly", even though they do not read memory. According to the comments this was done as an attempt to model changes to the FP rounding mode. This is too conservative, and unnecessarily blocks transformations such as commoning and vectorization. I have heard from others that FP

...ntext. For example, we don't model it for multiply and divide, so modeling it for sqrt seems pointless and in impedes a huge number of optimizations. -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://lists.llvm.org/pipermail/llvm-dev/attachments/20140124/175e37f5/attachment.html>