Commit Graph

4 Commits

Author SHA1 Message Date
Max Kazantsev 531db9a504 [EarlyCSE] Mark the condition of assume intrinsic as true
EarlyCSE should not just ignore assumes. It should use the fact that its condition is true for all dominated instructions.

Reviewers: sanjoy, reames, apilipenko, anna, skatkov

Reviewed By: reames, sanjoy

Subscribers: llvm-commits

Differential Revision: https://reviews.llvm.org/D32482

llvm-svn: 301625
2017-04-28 06:25:39 +00:00
Max Kazantsev 0589d9fa0f [EarlyCSE] Remove guards with conditions known to be true
If a condition is calculated only once, and there are multiple guards on this condition, we should be able
to remove all guards dominated by the first of them. This patch allows EarlyCSE to try to find the condition
of a guard among the known values, and if it is true, remove the guard. Otherwise we keep the guard and
mark its condition as 'true' for future consideration.

Reviewers: sanjoy, reames, apilipenko, skatkov, anna, dberlin

Reviewed By: reames, sanjoy

Subscribers: llvm-commits

Differential Revision: https://reviews.llvm.org/D32476

llvm-svn: 301623
2017-04-28 06:05:48 +00:00
Geoff Berry 8d84605f25 [EarlyCSE] Optionally use MemorySSA. NFC.
Summary:
Use MemorySSA, if requested, to do less conservative memory dependency
checking.

This change doesn't enable the MemorySSA enhanced EarlyCSE in the
default pipelines, so should be NFC.

Reviewers: dberlin, sanjoy, reames, majnemer

Subscribers: mcrosier, llvm-commits

Differential Revision: http://reviews.llvm.org/D19821

llvm-svn: 280279
2016-08-31 19:24:10 +00:00
Sanjoy Das ee81b23fe7 [EarlyCSE] Simplify guard intrinsics
Summary:
This change teaches EarlyCSE some basic properties of guard intrinsics:

 - Guard intrinsics read all memory, but don't write to any memory
 - After a guard has executed, the condition it was guarding on can be
   assumed to be true
 - Guard intrinsics on a constant `true` are no-ops

Reviewers: reames, hfinkel

Subscribers: mcrosier, llvm-commits

Differential Revision: http://reviews.llvm.org/D19578

llvm-svn: 268120
2016-04-29 21:52:58 +00:00