Now that the OpenMPOpt module pass include important optimizations for removing
globalization from offloading regions it should be run at a lower optimization
level.
Reviewed By: jdoerfert
Differential Revision: https://reviews.llvm.org/D105056
Addition of this pass has been botched.
There is no particular reason why it had to be sold as an inseparable part
of new-pm transition. It was added when old-pm was still the default,
and very *very* few users were actually tracking new-pm,
so it's effects weren't measured.
Which means, some of the turnoil of the new-pm transition
are actually likely regressions due to this pass.
Likewise, there has been a number of post-commit feedback
(post new-pm switch), namely
* https://reviews.llvm.org/D37467#2787157 (regresses HW-loops)
* https://reviews.llvm.org/D37467#2787259 (should not be in middle-end, should run after LSR, not before)
* https://reviews.llvm.org/D95789 (an attempt to fix bad loop backedge metadata)
and in the half year past, the pass authors (google) still haven't found time to respond to any of that.
Hereby it is proposed to backout the pass from the pipeline,
until someone who cares about it can address the issues reported,
and properly start the process of adding a new pass into the pipeline,
with proper performance evaluation.
Furthermore, neither google nor facebook reports any perf changes
from this change, so i'm dropping the pass completely.
It can always be re-reverted should/if anyone want to pick it up again.
Reviewed By: aeubanks
Differential Revision: https://reviews.llvm.org/D104099
This adds a function specialization pass to LLVM. Constant parameters
like function pointers and constant globals are propagated to the callee by
specializing the function.
This is a first version with a number of limitations:
- The pass is off by default, so needs to be enabled on the command line,
- It does not handle specialization of recursive functions,
- It does not yet handle constants and constant ranges,
- Only 1 argument per function is specialised,
- The cost-model could be further looked into, and perhaps related,
- We are not yet caching analysis results.
This is based on earlier work by Matthew Simpson (D36432) and Vinay Madhusudan.
More recently this was also discussed on the list, see:
https://lists.llvm.org/pipermail/llvm-dev/2021-March/149380.html.
The motivation for this work is that function specialisation often comes up as
a reason for performance differences of generated code between LLVM and GCC,
which has this enabled by default from optimisation level -O3 and up. And while
this certainly helps a few cpu benchmark cases, this also triggers in real
world codes and is thus a generally useful transformation to have in LLVM.
Function specialisation has great potential to increase compile-times and
code-size. The summary from some investigations with this patch is:
- Compile-time increases for short compile jobs is high relatively, but the
increase in absolute numbers still low.
- For longer compile-jobs, the extra compile time is around 1%, and very much
in line with GCC.
- It is difficult to blame one thing for compile-time increases: it looks like
everywhere a little bit more time is spent processing more functions and
instructions.
- But the function specialisation pass itself is not very expensive; it doesn't
show up very high in the profile of the optimisation passes.
The goal of this work is to reach parity with GCC which means that eventually
we would like to get this enabled by default. But first we would like to address
some of the limitations before that.
Differential Revision: https://reviews.llvm.org/D93838
This patch changes LoopUnrollAndJamPass from FunctionPass to LoopNest pass.
The next patch will utilize LoopNest to effectively handle loop nests.
Also, a crash problem on legacy pass manager is fixed.
Reviewed By: Whitney
Differential Revision: https://reviews.llvm.org/D99149
This pass transforms loops that contain a conditional branch with induction
variable. For example, it transforms left code to right code:
newbound = min(n, c)
while (iv < n) { while(iv < newbound) {
A A
if (iv < c) B
B C
C }
} if (iv != n) {
while (iv < n) {
A
C
}
}
Differential Revision: https://reviews.llvm.org/D102234
This is split off from D102002, and I think it is clear that
the difference in behavior was not intended. Options were
added to SimplifyCFG over time, but different chunks of
the pass pipelines were not kept in sync.
This patch changes LoopFlattenPass from FunctionPass to LoopNestPass.
Utilize LoopNest and let function 'Flatten' generate information from it.
Reviewed By: Whitney
Differential Revision: https://reviews.llvm.org/D102904
This patch changes LoopFlattenPass from FunctionPass to LoopNestPass.
Utilize LoopNest and let function 'Flatten' generate information from it.
Reviewed By: Whitney
Differential Revision: https://reviews.llvm.org/D102904
This patch changes LoopFlattenPass from FunctionPass to LoopNestPass.
Utilize LoopNest and let function 'Flatten' generate information from it.
Reviewed By: Whitney
Differential Revision: https://reviews.llvm.org/D102904
This patch changes LoopUnrollAndJamPass from FunctionPass to LoopNest pass.
The next patch will utilize LoopNest to effectively handle loop nests.
Reviewed By: Whitney
Differential Revision: https://reviews.llvm.org/D99149
This patch changes LoopUnrollAndJamPass from FunctionPass to LoopNest pass.
The next patch will utilize LoopNest to effectively handle loop nests.
Reviewed By: Whitney
Differential Revision: https://reviews.llvm.org/D99149
This patch changes LoopUnrollAndJamPass from FunctionPass to LoopNest pass.
The next patch will utilize LoopNest to effectively handle loop nests.
Reviewed By: Whitney
Differential Revision: https://reviews.llvm.org/D99149
This patch adjusts the LTO pipeline in the new PM to run GlobalsAA
before LICM to match the legacy PM.
This fixes a regression where the new PM failed to vectorize loops that
require hoisting/sinking by LICM depending on GlobalsAA info.
Reviewed By: aeubanks
Differential Revision: https://reviews.llvm.org/D102345
Split off from D102345 to commit this separately from other changes in
the patch. This aligns the behavior of the new PM with the legacy PM
for LTO, with respect to running LICM.
Together with the remaining changes in D102345, this fixes new PM
regressions where we fail to vectorize loops that are vectorized with
the legacy PM.
This is better no-functional-change-intended than the 1st attempt.
As noted in D102002, there were at least 2 diffs that went
unchecked in pass manager regressions tests: different pass
parameters (SimplifyCFG) and an extension point/callback.
Those should be lifted from the original code blocks correctly
now.
This reverts commit fefcb1f878.
It was supposed to be NFC, but as noted in the post-commit
comments in D102002, that was not true: SimplifyCFG uses
different parameters and there's a difference in an
extension point / callback.
Printing pass manager invocations is fairly verbose and not super
useful.
This allows us to remove DebugLogging from pass managers and PassBuilder
since all logging (aside from analysis managers) goes through
instrumentation now.
This has the downside of never being able to print the top level pass
manager via instrumentation, but that seems like a minor downside.
Reviewed By: ychen
Differential Revision: https://reviews.llvm.org/D101797
The CGSCC pass manager interplay with the FunctionAnalysisManagerCGSCCProxy is 'special' in the sense that the former will rerun the latter if there are changes to a SCC structure; that being said, some of the functions in the SCC may be unchanged. In that case, the function simplification pipeline will be re-run, which impacts compile time[1].
This patch allows the function simplification pipeline be skipped if it was already run and the function was not modified since.
The behavior is currently disabled by default. This is because, currently, the rerunning of the function simplification pipeline on an unchanged function may still result in changes. The patch simplifies investigating and fixing those cases where repeated function pass runs do actually positively impact code quality, while offering an easy workaround for those impacted negatively by compile time regressions, and not impacting mainline scenarios.
[1] A [[ http://llvm-compile-time-tracker.com/compare.php?from=eb37d3546cd0c6e67798496634c45e501f7806f1&to=ac722d1190dc7bbdd17e977ef7ec95e69eefc91e&stat=instructions | compile time tracker ]] run with the option enabled.
Differential Revision: https://reviews.llvm.org/D98103
GlobalsAA is only created at the beginning of the inliner pipeline. If
an AAManager is cached from previous passes, it won't get rebuilt to
include the newly created GlobalsAA.
Reviewed By: mtrofin
Differential Revision: https://reviews.llvm.org/D101379
Relative look table converter pass caused an issue when full lto
is enabled (reported in https://reviews.llvm.org/D94355).
This patch disables that pass from full lto pre-link phase optimization
pipeline until the issue is fixed.
Differential Revision: https://reviews.llvm.org/D101664
Hoisting and sinking instructions out of conditional blocks enables
additional vectorization by:
1. Executing memory accesses unconditionally.
2. Reducing the number of instructions that need predication.
After disabling early hoisting / sinking, we miss out on a few
vectorization opportunities. One of those is causing a ~10% performance
regression in one of the Geekbench benchmarks on AArch64.
This patch tires to recover the regression by running hoisting/sinking
as part of a SimplifyCFG run after LoopRotate and before LoopVectorize.
Note that in the legacy pass-manager, we run LoopRotate just before
vectorization again and there's no SimplifyCFG run in between, so the
sinking/hoisting may impact the later run on LoopRotate. But the impact
should be limited and the benefit of hosting/sinking at this stage
should outweigh the risk of not rotating.
Compile-time impact looks slightly positive for most cases.
http://llvm-compile-time-tracker.com/compare.php?from=2ea7fb7b1c045a7d60fcccf3df3ebb26aa3699e5&to=e58b4a763c691da651f25996aad619cb3d946faf&stat=instructions
NewPM-O3: geomean -0.19%
NewPM-ReleaseThinLTO: geoman -0.54%
NewPM-ReleaseLTO-g: geomean -0.03%
With a few benchmarks seeing a notable increase, but also some
improvements.
Alternative to D101290.
Reviewed By: lebedev.ri
Differential Revision: https://reviews.llvm.org/D101468
Summary:
This patch registers OpenMPOpt as a Module pass in addition to a CGSCC
pass. This is so certain optimzations that are sensitive to intact
call-sites can happen before inlining. The old `openmpopt` pass name is
changed to `openmp-opt-cgscc` and `openmp-opt` calls the Module pass.
The current module pass only runs a single check but will be expanded in
the future.
Reviewed By: jdoerfert
Differential Revision: https://reviews.llvm.org/D99202
Lookup tables generate non PIC-friendly code, which requires dynamic relocation as described in:
https://bugs.llvm.org/show_bug.cgi?id=45244
This patch adds a new pass that converts lookup tables to relative lookup tables to make them PIC-friendly.
Differential Revision: https://reviews.llvm.org/D94355
Retry of 330619a3a6 that includes a clang test update.
Original commit message:
If we run passes before lowering llvm.expect intrinsics to metadata,
then those passes have no way to act on the hints provided by llvm.expect.
SimplifyCFG is the known offender, and we made it smarter about profile
metadata in D98898 <https://reviews.llvm.org/D98898>.
In the motivating example from https://llvm.org/PR49336 , this means we
were ignoring the recommended method for a programmer to tell the compiler
that a compare+branch is expensive. This change appears to solve that case -
the metadata survives to the backend, the compare order is as expected in IR,
and the backend does not do anything to reverse it.
We make the same change to the old pass manager to keep things synchronized.
Differential Revision: https://reviews.llvm.org/D100213
If we run passes before lowering llvm.expect intrinsics to metadata,
then those passes have no way to act on the hints provided by llvm.expect.
SimplifyCFG is the known offender, and we made it smarter about profile
metadata in D98898.
In the motivating example from https://llvm.org/PR49336 , this means we
were ignoring the recommended method for a programmer to tell the compiler
that a compare+branch is expensive. This change appears to solve that case -
the metadata survives to the backend, the compare order is as expected in IR,
and the backend does not do anything to reverse it.
We make the same change to the old pass manager to keep things synchronized.
Differential Revision: https://reviews.llvm.org/D100213
Lookup tables generate non PIC-friendly code, which requires dynamic relocation as described in:
https://bugs.llvm.org/show_bug.cgi?id=45244
This patch adds a new pass that converts lookup tables to relative lookup tables to make them PIC-friendly.
Differential Revision: https://reviews.llvm.org/D94355
Lookup tables generate non PIC-friendly code, which requires dynamic relocation as described in:
https://bugs.llvm.org/show_bug.cgi?id=45244
This patch adds a new pass that converts lookup tables to relative lookup tables to make them PIC-friendly.
Differential Revision: https://reviews.llvm.org/D94355
Summary:
The IR is saved in its print form before each pass is started and a
signal handler is registered. If the compilation crashes, the signal
handler will print the saved IR to dbgs(). This option
can be modified using -print-module-scope to get the IR for the complete
module. Note that this option only works with the new pass manager.
Author: Jamie Schmeiser <schmeise@ca.ibm.com>
Reviewed By: aeubanks (Arthur Eubanks) yrouban (Yevgeny Rouban)
Differential Revision: https://reviews.llvm.org/D86657
Lookup tables generate non PIC-friendly code, which requires dynamic relocation as described in:
https://bugs.llvm.org/show_bug.cgi?id=45244
This patch adds a new pass that converts lookup tables to relative lookup tables to make them PIC-friendly.
Differential Revision: https://reviews.llvm.org/D94355
D96109 was recently submitted which contains the refactored implementation of
-funique-internal-linakge-names by adding the unique suffixes in clang rather
than as an LLVM pass. Deleting the former implementation in this change.
Differential Revision: https://reviews.llvm.org/D98234
We have the `enable-loopinterchange` option in legacy pass manager but not in NPM.
Add `LoopInterchange` pass to the optimization pipeline (at the same position as before)
when `enable-loopinterchange` is turned on.
Reviewed By: aeubanks, fhahn
Differential Revision: https://reviews.llvm.org/D98116
We're running into undefined references using ThinLTO with -O0 on
Windows/Chrome. This fixes that.
This matches the legacy PM.
Reviewed By: tejohnson
Differential Revision: https://reviews.llvm.org/D97414
-O1 and above do dont call real optimizer pipeline in ThinLTO PreLink.
Also clang can't add PostLink OptimizerLastEPCallbacks for in-process ThinLTO.
This results in missing sanitizer passes with ThinLTO.
Simple working solution is just call OptimizerLastEPCallbacks
at the end of buildThinLTOPreLinkDefaultPipeline.
Differential Revision: https://reviews.llvm.org/D96320
For ThinLTO, PreLink ICP is skipped to favor better profile annotation during LTO PostLink. This change applies the same tweak for MonoLTO. Note that PreLink ICP not only makes PostLink profile annotation harder, it is also uncoordinated with PostLink ICP so duplicated ICP could happen.
Differential Revision: https://reviews.llvm.org/D97028
Joseph Huber