Second part of https://reviews.llvm.org/D40348.
Revision r318436 has extended all constants feeding a store to 64 bits
to allow for CSE on the SDAG. However, negative constants were zero extended
which made the constant being loaded appear to be a positive value larger than
16 bits. This resulted in long sequences to materialize such constants
rather than simply a "load immediate". This patch just sign-extends those
updated constants so that they remain 16-bit signed immediates if they started
out that way.
llvm-svn: 320368
This re-commits everything that was pulled in r314244. The transformation
is off by default (patch to enable it to follow). The code is refactored
to have a single entry-point and provide fine-grained control over patterns
that it selects. This patch also fixes the bugs in the original code.
Everything that failed with the original patch has been re-tested with this
patch (with the transformation turned on). So the patch to turn this on is
soon to follow.
Differential Revision: https://reviews.llvm.org/D38575
llvm-svn: 319434
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
As mentioned in https://reviews.llvm.org/D33718, this simply adds another
pattern to the compare elimination sequence and is committed without a
differential revision.
llvm-svn: 314060
Nemanja Ivanovic