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| author | Tim Northover <tnorthover@apple.com> | 2013-05-30 13:19:42 +0000 |
|---|---|---|
| committer | Tim Northover <tnorthover@apple.com> | 2013-05-30 13:19:42 +0000 |
| commit | 15983b80a0ceb224b74d2ee5ef53d3eed37dc03b (patch) | |
| tree | 04df22eecc061cf808aa3a7a8a33ba02dc2b8ebf /configure | |
| parent | 52d65ab72dcdb3b5de8b84743537355067819c31 (diff) | |
| download | external_llvm-15983b80a0ceb224b74d2ee5ef53d3eed37dc03b.zip external_llvm-15983b80a0ceb224b74d2ee5ef53d3eed37dc03b.tar.gz external_llvm-15983b80a0ceb224b74d2ee5ef53d3eed37dc03b.tar.bz2 | |
X86: use sub-register sequences for MOV*r0 operations
Instead of having a bunch of separate MOV8r0, MOV16r0, ... pseudo-instructions,
it's better to use a single MOV32r0 (which will expand to "xorl %reg, %reg")
and obtain other sizes with EXTRACT_SUBREG and SUBREG_TO_REG. The encoding is
smaller and partial register updates can sometimes be avoided.
Until recently, this sequence was a barrier to rematerialization though. That
should now be fixed so it's an appropriate time to make the change.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@182928 91177308-0d34-0410-b5e6-96231b3b80d8
Diffstat (limited to 'configure')
0 files changed, 0 insertions, 0 deletions