Commit Graph

3 Commits

Author SHA1 Message Date
Serguei Katkov 66182d6c38 [SimplifyCFG] Re-apply Relax restriction for folding unconditional branches
The commit rL308422 introduces a restriction for folding unconditional
branches. Specifically if empty block with unconditional branch leads to
header of the loop then elimination of this basic block is prohibited.
However it seems this condition is redundantly strict.
If elimination of this basic block does not introduce more back edges
then we can eliminate this block.

The patch implements this relax of restriction.

The test profile/Linux/counter_promo_nest.c in compiler-rt project
is updated to meet this change.

Reviewers: efriedma, mcrosier, pacxx, hsung, davidxl	
Reviewed By: pacxx
Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D42691

llvm-svn: 324572
2018-02-08 07:16:29 +00:00
Serguei Katkov 276b32bb14 Revert [SimplifyCFG] Relax restriction for folding unconditional branches
The patch causes the failure of the test
compiler-rt/test/profile/Linux/counter_promo_nest.c

To unblock buildbot, revert the patch while investigation is in progress.

Differential Revision: https://reviews.llvm.org/D42691

llvm-svn: 324214
2018-02-05 09:05:43 +00:00
Serguei Katkov 6e93980e82 [SimplifyCFG] Relax restriction for folding unconditional branches
The commit rL308422 introduces a restriction for folding unconditional
branches. Specifically if empty block with unconditional branch leads to
header of the loop then elimination of this basic block is prohibited.
However it seems this condition is redundantly strict.
If elimination of this basic block does not introduce more back edges
then we can eliminate this block.

The patch implements this relax of restriction.

Reviewers: efriedma, mcrosier, pacxx, hsung, davidxl	
Reviewed By: pacxx
Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D42691

llvm-svn: 324208
2018-02-05 07:56:43 +00:00