Commit Graph

7 Commits

Author SHA1 Message Date
Richard Smith ed8d76ec60 Explicitly enable the new pass manager in this test.
Otherwise it fails under -DENABLE_EXPERIMENTAL_NEW_PASS_MANAGER=OFF.
2021-03-25 18:10:36 -07:00
Sameer Sahasrabuddhe b92c8c22b9 [NewPM] Disable non-trivial loop-unswitch on targets with divergence
Unswitching a loop on a non-trivial divergent branch is expensive
since it serializes the execution of both version of the
loop. But identifying a divergent branch needs divergence analysis,
which is a function level analysis.

The legacy pass manager handles this dependency by isolating such a
loop transform and rerunning the required function analyses. This
functionality is currently missing in the new pass manager, and there
is no safe way for the SimpleLoopUnswitch pass to depend on
DivergenceAnalysis. So we conservatively assume that all non-trivial
branches are divergent if the target has divergence.

Reviewed By: tra

Differential Revision: https://reviews.llvm.org/D98958
2021-03-25 11:27:10 +00:00
Sameer Sahasrabuddhe c540ce9900 [AMDGPU] pin lit test divergent-unswitch.ll to the old pass manager
The loop-unswitch transform should not be performed on a loop whose
condition is divergent. For this to happen correctly, divergence
analysis must be available. The existing divergence analysis has not
been ported to the new pass manager yet. As a result, loop unswitching
on the new pass manager is currently unsafe on targets that care about
divergence.

This test is temporarily disabled to unblock work on the new pass
manager. The issue is now tracked in bug 48819.

Reviewed By: foad

Differential Revision: https://reviews.llvm.org/D95051
2021-01-20 22:02:09 +05:30
Eric Christopher cee313d288 Revert "Temporarily Revert "Add basic loop fusion pass.""
The reversion apparently deleted the test/Transforms directory.

Will be re-reverting again.

llvm-svn: 358552
2019-04-17 04:52:47 +00:00
Eric Christopher a863435128 Temporarily Revert "Add basic loop fusion pass."
As it's causing some bot failures (and per request from kbarton).

This reverts commit r358543/ab70da07286e618016e78247e4a24fcb84077fda.

llvm-svn: 358546
2019-04-17 02:12:23 +00:00
Matt Arsenault 3dbeefa978 AMDGPU: Mark all unspecified CC functions in tests as amdgpu_kernel
Currently the default C calling convention functions are treated
the same as compute kernels. Make this explicit so the default
calling convention can be changed to a non-kernel.

Converted with perl -pi -e 's/define void/define amdgpu_kernel void/'
on the relevant test directories (and undoing in one place that actually
wanted a non-kernel).

llvm-svn: 298444
2017-03-21 21:39:51 +00:00
Stanislav Mekhanoshin ee2dd785f6 Only unswitch loops with uniform conditions
Loop unswitching can be extremely harmful for a SIMT target. In case
if hoisted condition is not uniform a SIMT machine will execute both
clones of a loop sequentially. Therefor LoopUnswitch checks if the
condition is non-divergent.

Since DivergenceAnalysis adds an expensive PostDominatorTree analysis
not needed for non-SIMT targets a new option is added to avoid unneded
analysis initialization. The method getAnalysisUsage is called when
TargetTransformInfo is not yet available and we cannot use it here.
For that reason a new field DivergentTarget is added to PassManagerBuilder
to control the behavior and set this field from a target.

Differential Revision: https://reviews.llvm.org/D30796

llvm-svn: 298104
2017-03-17 17:13:41 +00:00