Commit Graph

3 Commits

Author SHA1 Message Date
Dmitri Gribenko 2bf8d77453 Revert "Reland "r364412 [ExpandMemCmp][MergeICmps] Move passes out of CodeGen into opt pipeline.""
This reverts commit r371502, it broke tests
(clang/test/CodeGenCXX/auto-var-init.cpp).

llvm-svn: 371507
2019-09-10 10:39:09 +00:00
Clement Courbet 612c260ec3 Reland "r364412 [ExpandMemCmp][MergeICmps] Move passes out of CodeGen into opt pipeline."
With a fix for sanitizer breakage (see explanation in D60318).

llvm-svn: 371502
2019-09-10 09:18:00 +00:00
Evandro Menezes a005c1ac4f [AArch64] Expand bcmp() for small block lengths
Patch D56593 by @courbet results in calls to `bcmp()` in some cases, should
the target support the it.  Unless `TTI::MemCmpExpansionOptions()`
is overridden by the target.

In a proprietary benchmark we see a performance drop of about 12% on PNG
compression before this patch, though it passes all tests.

This patch mirrors X86 for AArch64 and initializes
`TTI::MemCmpExpansionOptions()` to then expand calls to `bcmp()` when
appropriate.  No tuning of the parameters was performed, but, at this point,
it's enough to recover the performance drop above.

This problem also exists on ARM.  Once a consensus is reached for AArch64, we
can work to fix ARM as well.

Authors:
- Evandro Menezes (@evandro) <e.menezes@samsung.com>
- Brian Rzycki (@brzycki) <b.rzycki@samsung.com>

Differential revision: https://reviews.llvm.org/D64805

llvm-svn: 367898
2019-08-05 18:09:14 +00:00