On PowerPC, FNMSUB (both VSX and non-VSX version) means -(a*b-c). But
the backend used to generate these instructions regardless whether nsz
flag exists or not. If a*b-c==0, such transformation changes sign of
zero.
This patch introduces PPC specific FNMSUB ISD opcode, which may help
improving combined FMA code sequence.
Reviewed By: steven.zhang
Differential Revision: https://reviews.llvm.org/D76585
Summary:
This is follow up patch of https://reviews.llvm.org/D67595.
Adjust naming and the Commutable operands for additional patterns
to make it easier to read.
The testcase update also show that we can save some unecessary fmr as
well.
Reviewers: #powerpc, steven.zhang, hfinkel, nemanjai
Reviewed By: #powerpc, nemanjai
Subscribers: wuzish, hiraditya, kbarton, MaskRay, shchenz, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D68112
llvm-svn: 373652
`llc -march` is problematic because it only switches the target
architecture, but leaves the operating system unchanged. This
occasionally leads to indeterministic tests because the OS from
LLVM_DEFAULT_TARGET_TRIPLE is used.
However we can simply always use `llc -mtriple` instead. This changes
all the tests to do this to avoid people using -march when they copy and
paste parts of tests.
This patch:
- Removes -march if the .ll file already has a matching `target triple`
directive or -mtriple argument.
- In all other cases changes -march=ppc32/-march=ppc64 to
-mtriple=ppc32--/-mtriple=ppc64--
See also the discussion in https://reviews.llvm.org/D35287
llvm-svn: 309754
Currently we have a number of tests that fail with -verify-machineinstrs.
To detect this cases earlier we add the option to the testcases with the
exception of tests that will currently fail with this option. PR 27456 keeps
track of this failures.
No code review, as discussed with Hal Finkel.
llvm-svn: 277624
