In the past while, I've committed a number of patches in the PowerPC back end
aimed at eliminating comparison instructions. However, this causes some failures
in proprietary source and these issues are not observed in SPEC or any open
source packages I've been able to run.
As a result, I'm pulling the entire series and will refactor it to:
- Have a single entry point for easy control
- Have fine-grained control over which patterns we transform
A side-effect of this is that test cases for these patches (and modified by
them) are XFAIL-ed. This is a temporary measure as it is counter-productive
to remove/modify these test cases and then have to modify them again when
the refactored patch is recommitted.
The failure will be investigated in parallel to the refactoring effort and
the recommit will either have a fix for it or will leave this transformation
off by default until the problem is resolved.
llvm-svn: 314244
This patch re-commits the patch that was pulled out due to a
problem it caused, but with a fix for the problem. The fix
was reviewed separately by Eric Christopher and Hal Finkel.
Differential Revision: https://reviews.llvm.org/D38054
llvm-svn: 313978
introduce a miscompile bug.
There appears to be a bug where the generated code to extract the sign
bit doesn't work correctly for 32-bit inputs. I've replied to the
original commit pointing out the problem. I think I see by inspection
(and reading the manual for PPC) how to fix this, but I can't be 100%
confident and I also don't know what the best way to test this is.
Currently it seems nearly impossible to get the backend to hit this code
path, but the patch autohr is likely in a better position to craft such
test cases than I am, and based on where the bug is it should be easily
done.
Original commit message for r310346:
"""
[PowerPC] Eliminate compares - add i32 sext/zext handling for SETLE/SETGE
Adds handling for SETLE/SETGE comparisons on i32 values. Furthermore, it
adds the handling for the special case where RHS == 0.
Differential Revision: https://reviews.llvm.org/D34048
"""
llvm-svn: 310809
Adds handling for SETLE/SETGE comparisons on i32 values. Furthermore, it adds
the handling for the special case where RHS == 0.
Differential Revision: https://reviews.llvm.org/D34048
llvm-svn: 310346
Nemanja Ivanovic