diff options
| author | David Sehr <sehr@google.com> | 2013-03-05 00:02:23 +0000 |
|---|---|---|
| committer | David Sehr <sehr@google.com> | 2013-03-05 00:02:23 +0000 |
| commit | 6c4265a541c9e431961113c1a5d92fb4628bfe13 (patch) | |
| tree | b98b6adf1f9527b4ca89e194005765c3cc0b0ccf /lib/CodeGen | |
| parent | 880e8c0ad41345f353b819c51092baa8f05e1950 (diff) | |
The current X86 NOP padding uses one long NOP followed by the remainder in
one-byte NOPs. If the processor actually executes those NOPs, as it sometimes
does with aligned bundling, this can have a performance impact. From my
micro-benchmarks run on my one machine, a 15-byte NOP followed by twelve
one-byte NOPs is about 20% worse than a 15 followed by a 12. This patch
changes NOP emission to emit as many 15-byte (the maximum) as possible followed
by at most one shorter NOP.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@176464 91177308-0d34-0410-b5e6-96231b3b80d8
Diffstat (limited to 'lib/CodeGen')
0 files changed, 0 insertions, 0 deletions