[Clang] [P2025] Analyze only potential scopes for NRVO

Before the patch we calculated the NRVO candidate looking at the
variable's whole enclosing scope. The research in [P2025] shows that
looking a

[Clang] [P2025] Analyze only potential scopes for NRVO

Before the patch we calculated the NRVO candidate looking at the
variable's whole enclosing scope. The research in [P2025] shows that
looking at the variable's potential scope is better and covers more
cases where NRVO would be safe and desirable.

Many thanks to @Izaron for the original implementation.

Reviewed By: ChuanqiXu

Differential Revision: https://reviews.llvm.org/D119792

show more ...

[OpaquePtrs][Clang] Add -no-opaque-pointers to tests (NFC)

This adds -no-opaque-pointers to clang tests whose output will
change when opaque pointers are enabled by default. This is
intended to be p

[OpaquePtrs][Clang] Add -no-opaque-pointers to tests (NFC)

This adds -no-opaque-pointers to clang tests whose output will
change when opaque pointers are enabled by default. This is
intended to be part of the migration approach described in
https://discourse.llvm.org/t/enabling-opaque-pointers-by-default/61322/9.

The patch has been produced by replacing %clang_cc1 with
%clang_cc1 -no-opaque-pointers for tests that fail with opaque
pointers enabled. Worth noting that this doesn't cover all tests,
there's a remaining ~40 tests not using %clang_cc1 that will need
a followup change.

Differential Revision: https://reviews.llvm.org/D123115

show more ...

Remove -O1 from command line of nrvo.cpp

Also, check that NRVO currently isn't performed in test25. The checks
were accidentally removed when https://reviews.llvm.org/D122425 disabled
inlining.

Pass -disable-llvm-passes to avoid running llvm passes

Differential Revision: https://reviews.llvm.org/D122425

[Clang] [P2025] More exhaustive tests for NRVO

This is a preliminary patch ahead of D119792 (I'll rebase that one on top of this).
This shows what Clang's _current_ behaviour is for calculating NRVO

[Clang] [P2025] More exhaustive tests for NRVO

This is a preliminary patch ahead of D119792 (I'll rebase that one on top of this).
This shows what Clang's _current_ behaviour is for calculating NRVO in various
common cases. Then, in D119792 (and future patches), I'll be able to demostrate
exactly how LLVM IR for each of these cases changes.

Reviewed By: Quuxplusone

Differential Revision: https://reviews.llvm.org/D119927

show more ...

[NFC][clang] Autogenerate checklines in CodeGenCXX/nrvo.cpp

It checks IR after optimizations, which is inherently fragile,
and the results are now different after the recent patch.

[Clang/Test]: Rename enable_noundef_analysis to disable-noundef-analysis and turn it off by default

Turning on `enable_noundef_analysis` flag allows better codegen by removing freeze instructions.
I

[Clang/Test]: Rename enable_noundef_analysis to disable-noundef-analysis and turn it off by default

Turning on `enable_noundef_analysis` flag allows better codegen by removing freeze instructions.
I modified clang by renaming `enable_noundef_analysis` flag to `disable-noundef-analysis` and turning it off by default.

Test updates are made as a separate patch: D108453

Reviewed By: eugenis

Differential Revision: https://reviews.llvm.org/D105169

show more ...

Revert "[Clang/Test]: Rename enable_noundef_analysis to disable-noundef-analysis and turn it off by default"

This reverts commit aacfbb953eb705af2ecfeb95a6262818fa85dd92.

Revert "Fix lit test failu

Revert "[Clang/Test]: Rename enable_noundef_analysis to disable-noundef-analysis and turn it off by default"

This reverts commit aacfbb953eb705af2ecfeb95a6262818fa85dd92.

Revert "Fix lit test failures in CodeGenCoroutines"

This reverts commit 63fff0f5bffe20fa2c84a45a41161afa0043cb34.

show more ...

[Clang/Test]: Rename enable_noundef_analysis to disable-noundef-analysis and turn it off by default

Turning on `enable_noundef_analysis` flag allows better codegen by removing freeze instructions.
I

[Clang/Test]: Rename enable_noundef_analysis to disable-noundef-analysis and turn it off by default

Turning on `enable_noundef_analysis` flag allows better codegen by removing freeze instructions.
I modified clang by renaming `enable_noundef_analysis` flag to `disable-noundef-analysis` and turning it off by default.

Test updates are made as a separate patch: D108453

Reviewed By: eugenis

Differential Revision: https://reviews.llvm.org/D105169

[Clang/Test]: Rename enable_noundef_analysis to disable-noundef-analysis and turn it off by default (2)

This patch updates test files after D105169.
Autogenerated test codes are changed by `utils/update_cc_test_checks.py,` and non-autogenerated test codes are changed as follows:

(1) I wrote a python script that (partially) updates the tests using regex: {F18594904} The script is not perfect, but I believe it gives hints about which patterns are updated to have `noundef` attached.

(2) The remaining tests are updated manually.

Reviewed By: eugenis

Differential Revision: https://reviews.llvm.org/D108453

Resolve lit failures in clang after 8ca4b3e's land

Fix lit test failures in clang-ppc* and clang-x64-windows-msvc

Fix missing failures in clang-ppc64be* and retry fixing clang-x64-windows-msvc

Fix internal_clone(aarch64) inline assembly

show more ...

Revert "[Clang/Test]: Rename enable_noundef_analysis to disable-noundef-analysis and turn it off by default"

This reverts commit 7584ef766a7219b6ee5a400637206d26e0fa98ac.

[Clang/Test]: Rename enable_noundef_analysis to disable-noundef-analysis and turn it off by default

Turning on `enable_noundef_analysis` flag allows better codegen by removing freeze instructions.
I

[Clang/Test]: Rename enable_noundef_analysis to disable-noundef-analysis and turn it off by default

Turning on `enable_noundef_analysis` flag allows better codegen by removing freeze instructions.
I modified clang by renaming `enable_noundef_analysis` flag to `disable-noundef-analysis` and turning it off by default.

Test updates are made as a separate patch: D108453

Reviewed By: eugenis

Differential Revision: https://reviews.llvm.org/D105169

show more ...

[test] Remove tests pinned to the legacy PM

Now that the legacy PM is deprecated for the optimization pipeline, we
can start deleting legacy PM tests.

For tests that test both PMs, merge the RUN li

[test] Remove tests pinned to the legacy PM

Now that the legacy PM is deprecated for the optimization pipeline, we
can start deleting legacy PM tests.

For tests that test both PMs, merge the RUN lines.
Delete tests specific to the legacy PM.

show more ...

Revert D105169 due to the two-stage failure in ASAN

This reverts the following commits:
37ca7a795b277c20c02a218bf44052278c03344b
9aa6c72b92b6c89cc6d23b693257df9af7de2d15
705387c5074bcca36d626882462e

Revert D105169 due to the two-stage failure in ASAN

This reverts the following commits:
37ca7a795b277c20c02a218bf44052278c03344b
9aa6c72b92b6c89cc6d23b693257df9af7de2d15
705387c5074bcca36d626882462ebbc2bcc3bed4
8ca4b3ef19fe82d7ad6a6e1515317dcc01b41515
80dba72a669b5416e97a42fd2c2a7bc5a6d3f44a

show more ...

[Clang/Test]: Rename enable_noundef_analysis to disable-noundef-analysis and turn it off by default (2)

This patch updates test files after D105169.
Autogenerated test codes are changed by `utils/up

[Clang/Test]: Rename enable_noundef_analysis to disable-noundef-analysis and turn it off by default (2)

This patch updates test files after D105169.
Autogenerated test codes are changed by `utils/update_cc_test_checks.py,` and non-autogenerated test codes are changed as follows:

(1) I wrote a python script that (partially) updates the tests using regex: {F18594904} The script is not perfect, but I believe it gives hints about which patterns are updated to have `noundef` attached.

(2) The remaining tests are updated manually.

Reviewed By: eugenis

Differential Revision: https://reviews.llvm.org/D108453

show more ...

[test] Add {{.*}} to make ELF tests immune to dso_local/dso_preemptable/(none) differences

For a default visibility external linkage definition, dso_local is set for ELF
-fno-pic/-fpie and COFF and

[test] Add {{.*}} to make ELF tests immune to dso_local/dso_preemptable/(none) differences

For a default visibility external linkage definition, dso_local is set for ELF
-fno-pic/-fpie and COFF and Mach-O. Since default clang -cc1 for ELF is similar
to -fpic ("PIC Level" is not set), this nuance causes unneeded binary format differences.

To make emitted IR similar, ELF -cc1 -fpic will default to -fno-semantic-interposition,
which sets dso_local for default visibility external linkage definitions.

To make this flip smooth and enable future (dso_local as definition default),
this patch replaces (function) `define ` with `define{{.*}} `,
(variable/constant/alias) `= ` with `={{.*}} `, or inserts appropriate `{{.*}} `.

show more ...

[CodeGen] Apply 'nonnull' and 'dereferenceable(N)' to 'this' pointer
arguments.

* Adds 'nonnull' and 'dereferenceable(N)' to 'this' pointer arguments
* Gates 'nonnull' on -f(no-)delete-null-pointer-

[CodeGen] Apply 'nonnull' and 'dereferenceable(N)' to 'this' pointer
arguments.

* Adds 'nonnull' and 'dereferenceable(N)' to 'this' pointer arguments
* Gates 'nonnull' on -f(no-)delete-null-pointer-checks
* Introduces this-nonnull.cpp and microsoft-abi-this-nullable.cpp tests to
explicitly test the behavior of this change
* Refactors hundreds of over-constrained clang tests to permit these
attributes, where needed
* Updates Clang12 patch notes mentioning this change

Reviewed-by: rsmith, jdoerfert

Differential Revision: https://reviews.llvm.org/D17993

show more ...

[NFC][clang] Adjust test/CodeGenCXX/nrvo.cpp after 03127f795b8244c1039c18d4391374707a3dc75e

[InstCombine] Aggregate reconstruction simplification (PR47060)

This pattern happens in clang C++ exception lowering code, on unwind branch.
We end up having a `landingpad` block after each `invoke`

[InstCombine] Aggregate reconstruction simplification (PR47060)

This pattern happens in clang C++ exception lowering code, on unwind branch.
We end up having a `landingpad` block after each `invoke`, where RAII
cleanup is performed, and the elements of an aggregate `{i8*, i32}`
holding exception info are `extractvalue`'d, and we then branch to common block
that takes extracted `i8*` and `i32` elements (via `phi` nodes),
form a new aggregate, and finally `resume`'s the exception.

The problem is that, if the cleanup block is effectively empty,
it shouldn't be there, there shouldn't be that `landingpad` and `resume`,
said `invoke` should be a `call`.

Indeed, we do that simplification in e.g. SimplifyCFG `SimplifyCFGOpt::simplifyResume()`.
But the thing is, all this extra `extractvalue` + `phi` + `insertvalue` cruft,
while it is pointless, does not look like "empty cleanup block".
So the `SimplifyCFGOpt::simplifyResume()` fails, and the exception is has
higher cost than it could have on unwind branch :S

This doesn't happen *that* often, but it will basically happen once per C++
function with complex CFG that called more than one other function
that isn't known to be `nounwind`.

I think, this is a missing fold in InstCombine, so i've implemented it.

I think, the algorithm/implementation is rather self-explanatory:
1. Find a chain of `insertvalue`'s that fully tell us the initializer of the aggregate.
2. For each element, try to find from which aggregate it was extracted.
If it was extracted from the aggregate with identical type,
from identical element index, great.
3. If all elements were found to have been extracted from the same aggregate,
then we can just use said original source aggregate directly,
instead of re-creating it.
4. If we fail to find said aggregate when looking only in the current block,
we need be PHI-aware - we might have different source aggregate when coming
from each predecessor.

I'm not sure if this already handles everything, and there are some FIXME's,
i'll deal with all that later in followups.

I'd be fine with going with post-commit review here code-wise,
but just in case there are thoughts, i'm posting this.

On RawSpeed, for example, this has the following effect:
```
| statistic name | baseline | proposed | Δ | % | abs(%) |
|---------------------------------------------------|---------:|---------:|------:|--------:|-------:|
| instcombine.NumAggregateReconstructionsSimplified | 0 | 1253 | 1253 | 0.00% | 0.00% |
| simplifycfg.NumInvokes | 948 | 1355 | 407 | 42.93% | 42.93% |
| instcount.NumInsertValueInst | 4382 | 3210 | -1172 | -26.75% | 26.75% |
| simplifycfg.NumSinkCommonCode | 574 | 458 | -116 | -20.21% | 20.21% |
| simplifycfg.NumSinkCommonInstrs | 1154 | 921 | -233 | -20.19% | 20.19% |
| instcount.NumExtractValueInst | 29017 | 26397 | -2620 | -9.03% | 9.03% |
| instcombine.NumDeadInst | 166618 | 174705 | 8087 | 4.85% | 4.85% |
| instcount.NumPHIInst | 51526 | 50678 | -848 | -1.65% | 1.65% |
| instcount.NumLandingPadInst | 20865 | 20609 | -256 | -1.23% | 1.23% |
| instcount.NumInvokeInst | 34023 | 33675 | -348 | -1.02% | 1.02% |
| simplifycfg.NumSimpl | 113634 | 114708 | 1074 | 0.95% | 0.95% |
| instcombine.NumSunkInst | 15030 | 14930 | -100 | -0.67% | 0.67% |
| instcount.TotalBlocks | 219544 | 219024 | -520 | -0.24% | 0.24% |
| instcombine.NumCombined | 644562 | 645805 | 1243 | 0.19% | 0.19% |
| instcount.TotalInsts | 2139506 | 2135377 | -4129 | -0.19% | 0.19% |
| instcount.NumBrInst | 156988 | 156821 | -167 | -0.11% | 0.11% |
| instcount.NumCallInst | 1206144 | 1207076 | 932 | 0.08% | 0.08% |
| instcount.NumResumeInst | 5193 | 5190 | -3 | -0.06% | 0.06% |
| asm-printer.EmittedInsts | 948580 | 948299 | -281 | -0.03% | 0.03% |
| instcount.TotalFuncs | 11509 | 11507 | -2 | -0.02% | 0.02% |
| inline.NumDeleted | 97595 | 97597 | 2 | 0.00% | 0.00% |
| inline.NumInlined | 210514 | 210522 | 8 | 0.00% | 0.00% |
```
So we manage to increase the amount of `invoke` -> `call` conversions in SimplifyCFG by almost a half,
and there is a very apparent decrease in instruction and basic block count.

On vanilla llvm-test-suite:
```
| statistic name | baseline | proposed | Δ | % | abs(%) |
|---------------------------------------------------|---------:|---------:|------:|--------:|-------:|
| instcombine.NumAggregateReconstructionsSimplified | 0 | 744 | 744 | 0.00% | 0.00% |
| instcount.NumInsertValueInst | 2705 | 2053 | -652 | -24.10% | 24.10% |
| simplifycfg.NumInvokes | 1212 | 1424 | 212 | 17.49% | 17.49% |
| instcount.NumExtractValueInst | 21681 | 20139 | -1542 | -7.11% | 7.11% |
| simplifycfg.NumSinkCommonInstrs | 14575 | 14361 | -214 | -1.47% | 1.47% |
| simplifycfg.NumSinkCommonCode | 6815 | 6743 | -72 | -1.06% | 1.06% |
| instcount.NumLandingPadInst | 14851 | 14712 | -139 | -0.94% | 0.94% |
| instcount.NumInvokeInst | 27510 | 27332 | -178 | -0.65% | 0.65% |
| instcombine.NumDeadInst | 1438173 | 1443371 | 5198 | 0.36% | 0.36% |
| instcount.NumResumeInst | 2880 | 2872 | -8 | -0.28% | 0.28% |
| instcombine.NumSunkInst | 55187 | 55076 | -111 | -0.20% | 0.20% |
| instcount.NumPHIInst | 321366 | 320916 | -450 | -0.14% | 0.14% |
| instcount.TotalBlocks | 886816 | 886493 | -323 | -0.04% | 0.04% |
| instcount.TotalInsts | 7663845 | 7661108 | -2737 | -0.04% | 0.04% |
| simplifycfg.NumSimpl | 886791 | 887171 | 380 | 0.04% | 0.04% |
| instcount.NumCallInst | 553552 | 553733 | 181 | 0.03% | 0.03% |
| instcombine.NumCombined | 3200512 | 3201202 | 690 | 0.02% | 0.02% |
| instcount.NumBrInst | 741794 | 741656 | -138 | -0.02% | 0.02% |
| simplifycfg.NumHoistCommonInstrs | 14443 | 14445 | 2 | 0.01% | 0.01% |
| asm-printer.EmittedInsts | 7978085 | 7977916 | -169 | 0.00% | 0.00% |
| inline.NumDeleted | 73188 | 73189 | 1 | 0.00% | 0.00% |
| inline.NumInlined | 291959 | 291968 | 9 | 0.00% | 0.00% |
```
Roughly similar effect, less instructions and blocks total.

See also: rGe492f0e03b01a5e4ec4b6333abb02d303c3e479e.

Compile-time wise, this appears to be roughly geomean-neutral:
http://llvm-compile-time-tracker.com/compare.php?from=39617aaed95ac00957979bc1525598c1be80e85e&to=b59866cf30420da8f8e3ca239ed3bec577b23387&stat=instructions

And this is a win size-wize in general:
http://llvm-compile-time-tracker.com/compare.php?from=39617aaed95ac00957979bc1525598c1be80e85e&to=b59866cf30420da8f8e3ca239ed3bec577b23387&stat=size-text

See https://bugs.llvm.org/show_bug.cgi?id=47060

Reviewed By: spatel

Differential Revision: https://reviews.llvm.org/D85787

show more ...

[CGCall] Annotate references with "align" attribute.

If we're going to assume references are dereferenceable, we should also
assume they're aligned: otherwise, we can't actually dereference them.

S

[CGCall] Annotate references with "align" attribute.

If we're going to assume references are dereferenceable, we should also
assume they're aligned: otherwise, we can't actually dereference them.

See also D80072.

Differential Revision: https://reviews.llvm.org/D80166

show more ...

Revert "[CodeGenModule] Assume dso_local for -fpic -fno-semantic-interposition"

This reverts commit 789a46f2d742e11edaade28cb59a0f4d2a1d770e.

Accidentally committed.

[CodeGenModule] Assume dso_local for -fpic -fno-semantic-interposition

Summary:
Clang -fpic defaults to -fno-semantic-interposition (GCC -fpic defaults
to -fsemantic-interposition).
Users need to sp

[CodeGenModule] Assume dso_local for -fpic -fno-semantic-interposition

Summary:
Clang -fpic defaults to -fno-semantic-interposition (GCC -fpic defaults
to -fsemantic-interposition).
Users need to specify -fsemantic-interposition to get semantic
interposition behavior.

Semantic interposition is currently a best-effort feature. There may
still be some cases where it is not handled well.

Reviewers: peter.smith, rnk, serge-sans-paille, sfertile, jfb, jdoerfert

Subscribers: dschuff, jyknight, dylanmckay, nemanjai, jvesely, kbarton, fedor.sergeev, asb, rbar, johnrusso, simoncook, sabuasal, niosHD, jrtc27, zzheng, edward-jones, atanasyan, rogfer01, MartinMosbeck, brucehoult, the_o, arphaman, PkmX, jocewei, jsji, Jim, lenary, s.egerton, pzheng, sameer.abuasal, apazos, luismarques, cfe-commits

Tags: #clang

Differential Revision: https://reviews.llvm.org/D73865

show more ...

Revert "Revert "As a follow-up to my initial mail to llvm-dev here's a first pass at the O1 described there.""

This reapplies: 8ff85ed905a7306977d07a5cd67ab4d5a56fafb4

Original commit message:

As

Revert "Revert "As a follow-up to my initial mail to llvm-dev here's a first pass at the O1 described there.""

This reapplies: 8ff85ed905a7306977d07a5cd67ab4d5a56fafb4

Original commit message:

As a follow-up to my initial mail to llvm-dev here's a first pass at the O1 described there.

This change doesn't include any change to move from selection dag to fast isel
and that will come with other numbers that should help inform that decision.
There also haven't been any real debuggability studies with this pipeline yet,
this is just the initial start done so that people could see it and we could start
tweaking after.

Test updates: Outside of the newpm tests most of the updates are coming from either
optimization passes not run anymore (and without a compelling argument at the moment)
that were largely used for canonicalization in clang.

Original post:

http://lists.llvm.org/pipermail/llvm-dev/2019-April/131494.html

Tags: #llvm
Differential Revision: https://reviews.llvm.org/D65410

This reverts commit c9ddb02659e3ece7a0d9d6b4dac7ceea4ae46e6d.

show more ...

Revert "As a follow-up to my initial mail to llvm-dev here's a first pass at the O1 described there."

This reverts commit 8ff85ed905a7306977d07a5cd67ab4d5a56fafb4.

This commit introduced 9 new fail

Revert "As a follow-up to my initial mail to llvm-dev here's a first pass at the O1 described there."

This reverts commit 8ff85ed905a7306977d07a5cd67ab4d5a56fafb4.

This commit introduced 9 new failures on lldb buildbot host at http://lab.llvm.org:8014/builders/lldb-aarch64-ubuntu

Following tests were failing:
lldb-api :: functionalities/tail_call_frames/ambiguous_tail_call_seq1/TestAmbiguousTailCallSeq1.py
lldb-api :: functionalities/tail_call_frames/ambiguous_tail_call_seq2/TestAmbiguousTailCallSeq2.py
lldb-api :: functionalities/tail_call_frames/disambiguate_call_site/TestDisambiguateCallSite.py
lldb-api :: functionalities/tail_call_frames/disambiguate_paths_to_common_sink/TestDisambiguatePathsToCommonSink.py
lldb-api :: functionalities/tail_call_frames/disambiguate_tail_call_seq/TestDisambiguateTailCallSeq.py
lldb-api :: functionalities/tail_call_frames/inlining_and_tail_calls/TestInliningAndTailCalls.py
lldb-api :: functionalities/tail_call_frames/sbapi_support/TestTailCallFrameSBAPI.py
lldb-api :: functionalities/tail_call_frames/thread_step_out_message/TestArtificialFrameStepOutMessage.py
lldb-api :: functionalities/tail_call_frames/thread_step_out_or_return/TestSteppingOutWithArtificialFrames.py
lldb-api :: functionalities/tail_call_frames/unambiguous_sequence/TestUnambiguousTailCalls.py

Tags: #llvm
Differential Revision: https://reviews.llvm.org/D65410

show more ...

As a follow-up to my initial mail to llvm-dev here's a first pass at the O1 described there.

This change doesn't include any change to move from selection dag to fast isel
and that will come with ot

As a follow-up to my initial mail to llvm-dev here's a first pass at the O1 described there.

This change doesn't include any change to move from selection dag to fast isel
and that will come with other numbers that should help inform that decision.
There also haven't been any real debuggability studies with this pipeline yet,
this is just the initial start done so that people could see it and we could start
tweaking after.

Test updates: Outside of the newpm tests most of the updates are coming from either
optimization passes not run anymore (and without a compelling argument at the moment)
that were largely used for canonicalization in clang.

Original post:

http://lists.llvm.org/pipermail/llvm-dev/2019-April/131494.html

Tags: #llvm
Differential Revision: https://reviews.llvm.org/D65410

show more ...

Re-commit r357452 (take 3): "SimplifyCFG SinkCommonCodeFromPredecessors: Also sink function calls without used results (PR41259)"

Third time's the charm.

This was reverted in r363220 due to being s

Re-commit r357452 (take 3): "SimplifyCFG SinkCommonCodeFromPredecessors: Also sink function calls without used results (PR41259)"

Third time's the charm.

This was reverted in r363220 due to being suspected of an internal benchmark
regression and a test failure, none of which turned out to be caused by this.

llvm-svn: 363529

show more ...