Commit Graph

4 Commits

Author SHA1 Message Date
Chandler Carruth 4190b507c5 Flip the new block-placement pass to be on by default.
This is mostly to test the waters. I'd like to get results from FNT
build bots and other bots running on non-x86 platforms.

This feature has been pretty heavily tested over the last few months by
me, and it fixes several of the execution time regressions caused by the
inlining work by preventing inlining decisions from radically impacting
block layout.

I've seen very large improvements in yacr2 and ackermann benchmarks,
along with the expected noise across all of the benchmark suite whenever
code layout changes. I've analyzed all of the regressions and fixed
them, or found them to be impossible to fix. See my email to llvmdev for
more details.

I'd like for this to be in 3.1 as it complements the inliner changes,
but if any failures are showing up or anyone has concerns, it is just
a flag flip and so can be easily turned off.

I'm switching it on tonight to try and get at least one run through
various folks' performance suites in case SPEC or something else has
serious issues with it. I'll watch bots and revert if anything shows up.

llvm-svn: 154816
2012-04-16 13:49:17 +00:00
Benjamin Kramer 15cd5a3f12 Don't emit a bit test if there is only one case the test can yield false. A simple SETNE is sufficient.
llvm-svn: 135126
2011-07-14 01:38:42 +00:00
Evan Cheng ac730dd2d1 Avoid zero extend bit test operands to pointer type if all the masks fit in
the original type of the switch statement key.
rdar://8781238

llvm-svn: 122935
2011-01-06 01:02:44 +00:00
Dan Gohman 0695e09b09 Optimize the "bit test" code path for switch lowering in the
case where the bit mask has exactly one bit.

llvm-svn: 106716
2010-06-24 02:06:24 +00:00