[PATCH] D33186: [InstCombine] Canonicalize clamp of float types to minmax in fast mode.

[Andrei Elovikov via Phabricator via llvm-commits]

a.elovikov created this revision.

This commit allows matchSelectPattern to recognize clamp of float
arguments in the presence of FMF the same way as already done for
integers.

This case is a little different though. With integers, given the
min/max pattern is recognized, DAGBuilder starts selecting MIN/MAX
"automatically". That is not the case for float, because for them only
full FMINNAN/FMINNUM/FMAXNAN/FMAXNUM ISD nodes exist and they do care
about NaNs. On the other hand, some backends (e.g. X86) have only
FMIN/FMAX nodes that do not care about NaNS and the former NAN/NUM
nodes are illegal thus selection is not happening. So I decided to do
such kind of transformation in IR (InstCombiner) instead of
complicating the logic in the backend.


https://reviews.llvm.org/D33186

Files:
  llvm/include/llvm/IR/PatternMatch.h
  llvm/lib/Analysis/ValueTracking.cpp
  llvm/lib/Transforms/InstCombine/InstCombineSelect.cpp
  llvm/test/Transforms/InstCombine/clamp-to-minmax.ll

-------------- next part --------------
A non-text attachment was scrubbed...
Name: D33186.98978.patch
Type: text/x-patch
Size: 28646 bytes
Desc: not available
URL: <http://lists.llvm.org/pipermail/llvm-commits/attachments/20170515/75423c98/attachment.bin>