I may have given bad advice, and skipping sext_inreg when matching SSAT
patterns is not valid on it's own. It at least needs to sext_inreg the
input again, but as far as I can tell is still only valid based on
demanded bits. For the moment disable that part of the combine,
hopefully reimplementing it in the future more correctly.
LLVM will canonicalize conditional selectors to a different pattern than the old code that was used.
This is updating the function to match the new expected patterns and select SSAT or USAT when successful.
Tests have also been updated to use the new patterns.
Differential Review: https://reviews.llvm.org/D87379
The saturation instructions appeared in v6T2, with DSP extensions, but they
were being accepted / generated on any, with the new introduction of the
saturation detection in the back-end. This commit restricts the usage to
DSP-enable only cores.
Fixes PR28607.
llvm-svn: 276701
Summary:
SSAT saturates an integer, making sure that its value lies within
an interval [-k, k]. Since the constant is given to SSAT as the
number of bytes set to one, k + 1 must be a power of 2, otherwise
the optimization is not possible. Also, the select_cc must use <
and > respectively so that they define an interval.
Reviewers: mcrosier, jmolloy, rengolin
Subscribers: aemerson, rengolin, llvm-commits
Differential Revision: http://reviews.llvm.org/D21372
llvm-svn: 273581
David Green