19 Commits

Author SHA1 Message Date
Hari Limaye
7eca38ce76
Reland "[clang] Add nuw attribute to GEPs (#105496)" (#107257)
Add nuw attribute to inbounds GEPs where the expression used to form the
GEP is an addition of unsigned indices.

Relands #105496, which was reverted because it exposed a miscompilation
arising from #98608. This is now fixed by #106512.
2024-09-05 16:13:11 +01:00
Vitaly Buka
69437a392e
Revert "[clang] Add nuw attribute to GEPs" (#106343)
Reverts llvm/llvm-project#105496

This patch breaks:
https://lab.llvm.org/buildbot/#/builders/25/builds/1952
https://lab.llvm.org/buildbot/#/builders/52/builds/1775

Somehow output is different with sanitizers.
Maybe non-determinism in the code?
2024-08-28 12:14:04 +02:00
Hari Limaye
3d2fd31c8f
[clang] Add nuw attribute to GEPs (#105496)
Add nuw attribute to inbounds GEPs where the expression used to form the
GEP is an addition of unsigned indices.
2024-08-27 14:20:48 +01:00
Hari Limaye
94473f4db6
[IRBuilder] Generate nuw GEPs for struct member accesses (#99538)
Generate nuw GEPs for struct member accesses, as inbounds + non-negative
implies nuw.

Regression tests are updated using update scripts where possible, and by
find + replace where not.
2024-08-09 13:25:04 +01:00
Nikita Popov
158d72d728
[Clang] Set writable and dead_on_unwind attributes on sret arguments (#77116)
Set the writable and dead_on_unwind attributes for sret arguments. These
indicate that the argument points to writable memory (and it's legal to
introduce spurious writes to it on entry to the function) and that the
argument memory will not be used if the call unwinds.

This enables additional MemCpyOpt/DSE/LICM optimizations.
2024-01-11 09:46:54 +01:00
Aaron Ballman
84a3aadf0f Diagnose use of VLAs in C++ by default
Reapplication of 7339c0f782d5c70e0928f8991b0c05338a90c84c with a fix
for a crash involving arrays without a size expression.

Clang supports VLAs in C++ as an extension, but we currently only warn
on their use when you pass -Wvla, -Wvla-extension, or -pedantic.
However, VLAs as they're expressed in C have been considered by WG21
and rejected, are easy to use accidentally to the surprise of users
(e.g., https://ddanilov.me/default-non-standard-features/), and they
have potential security implications beyond constant-size arrays
(https://wiki.sei.cmu.edu/confluence/display/c/ARR32-C.+Ensure+size+arguments+for+variable+length+arrays+are+in+a+valid+range).
C++ users should strongly consider using other functionality such as
std::vector instead.

This seems like sufficiently compelling evidence to warn users about
VLA use by default in C++ modes. This patch enables the -Wvla-extension
diagnostic group in C++ language modes by default, and adds the warning
group to -Wall in GNU++ language modes. The warning is still opt-in in
C language modes, where support for VLAs is somewhat less surprising to
users.

RFC: https://discourse.llvm.org/t/rfc-diagnosing-use-of-vlas-in-c/73109
Fixes https://github.com/llvm/llvm-project/issues/62836
Differential Revision: https://reviews.llvm.org/D156565
2023-10-20 13:10:03 -04:00
Aaron Ballman
f5043f46c0 Revert "Diagnose use of VLAs in C++ by default"
This reverts commit 7339c0f782d5c70e0928f8991b0c05338a90c84c.

Breaks bots:
https://lab.llvm.org/buildbot/#/builders/139/builds/51875
https://lab.llvm.org/buildbot/#/builders/164/builds/45262
2023-10-20 10:00:18 -04:00
Aaron Ballman
7339c0f782 Diagnose use of VLAs in C++ by default
Clang supports VLAs in C++ as an extension, but we currently only warn
on their use when you pass -Wvla, -Wvla-extension, or -pedantic.
However, VLAs as they're expressed in C have been considered by WG21
and rejected, are easy to use accidentally to the surprise of users
(e.g., https://ddanilov.me/default-non-standard-features/), and they
have potential security implications beyond constant-size arrays
(https://wiki.sei.cmu.edu/confluence/display/c/ARR32-C.+Ensure+size+arguments+for+variable+length+arrays+are+in+a+valid+range).
C++ users should strongly consider using other functionality such as
std::vector instead.

This seems like sufficiently compelling evidence to warn users about
VLA use by default in C++ modes. This patch enables the -Wvla-extension
diagnostic group in C++ language modes by default, and adds the warning
group to -Wall in GNU++ language modes. The warning is still opt-in in
C language modes, where support for VLAs is somewhat less surprising to
users.

RFC: https://discourse.llvm.org/t/rfc-diagnosing-use-of-vlas-in-c/73109
Fixes https://github.com/llvm/llvm-project/issues/62836
Differential Revision: https://reviews.llvm.org/D156565
2023-10-20 09:50:21 -04:00
Matt Arsenault
25bc999d1f Intrinsics: Add type overload to stacksave and stackstore
This allows use with non-0 address space stacks. llvm_ptr_ty should
never be used. This could use some more percolation up through mlir,
but this is enough to fix existing tests.

https://reviews.llvm.org/D156666
2023-08-09 18:33:11 -04:00
Sergei Barannikov
8be4bd16ca [clang] Convert remaining OpenMP tests to opaque pointers
Reviewed By: nikic

Differential Revision: https://reviews.llvm.org/D150733
2023-05-17 23:27:43 +03:00
Itay Bookstein
782c59a4ee [OpenMP] Prefix outlined and reduction func names with original func's name
This patch prefixes omp outlined helpers and reduction funcs
with the original function's name.

Reviewed By: jdoerfert

Differential Revision: https://reviews.llvm.org/D140722
2023-04-19 23:00:26 +03:00
Itay Bookstein
6fdd13e0ec Revert "[OpenMP] Prefix outlined and reduction func names with original func's name"
This reverts commit 029bfc311d4d7d3cd90be81bb08c046848796d02.
2023-04-19 19:08:49 +03:00
Itay Bookstein
029bfc311d [OpenMP] Prefix outlined and reduction func names with original func's name
This patch attempts to prefix omp outlined helpers and reduction funcs
with the original function's name.

Reviewed By: jdoerfert

Differential Revision: https://reviews.llvm.org/D140722
2023-04-19 19:05:21 +03:00
Dhruva Chakrabarti
839ac62c50 Revert "[OpenMP] Codegen aggregate for outlined function captures"
This reverts commit 7539e9cf811e590d9f12ae39673ca789e26386b4.
2022-09-15 03:08:46 +00:00
Giorgis Georgakoudis
7539e9cf81 [OpenMP] Codegen aggregate for outlined function captures
Parallel regions are outlined as functions with capture variables explicitly generated as distinct parameters in the function's argument list. That complicates the fork_call interface in the OpenMP runtime: (1) the fork_call is variadic since there is a variable number of arguments to forward to the outlined function, (2) wrapping/unwrapping arguments happens in the OpenMP runtime, which is sub-optimal, has been a source of ABI bugs, and has a hardcoded limit (16) in the number of arguments, (3)  forwarded arguments must cast to pointer types, which complicates debugging. This patch avoids those issues by aggregating captured arguments in a struct to pass to the fork_call.

Reviewed By: jdoerfert, jhuber6, ABataev

Differential Revision: https://reviews.llvm.org/D102107
2022-09-15 00:54:05 +00:00
Nicolai Hähnle
1ddc51d89d Inliner: don't mark call sites as 'nounwind' if that would be redundant
When F calls G calls H, G is nounwind, and G is inlined into F, then the
inlined call-site to H should be effectively nounwind so as not to lose
information during inlining.

If H itself is nounwind (which often happens when H is an intrinsic), we
no longer mark the callsite explicitly as nounwind. Previously, there
were cases where the inlined call-site of H differs from a pre-existing
call-site of H in F *only* in the explicitly added nounwind attribute,
thus preventing common subexpression elimination.

v2:
- just check CI->doesNotThrow

v3 (resubmit after revert at 344378808778c61d5599f4e0ac783ef7e6f8ed05):
- update Clang tests

Differential Revision: https://reviews.llvm.org/D129860
2022-07-20 14:17:23 +02:00
Nicolai Hähnle
3d2256cc75 Revert "Update some more tests with update_cc_test_checks.py"
This reverts commit 9fb33d52b045b6cc97f2f56fe5cd23b41de86ffe.

Buildbots are showing a number of regressions that don't reproduce
locally. Needs more investigating.
2022-07-19 16:39:57 +02:00
Nicolai Hähnle
9fb33d52b0 Update some more tests with update_cc_test_checks.py 2022-07-19 16:18:35 +02:00
Ritanya B Bharadwaj
8322fe200d Adding support for target in_reduction
Implementing target in_reduction by wrapping target task with host task with in_reduction and if clause. This is in compliance with OpenMP 5.0 section: 2.19.5.6.
So, this

```
  for (int i=0; i<N; i++) {
    res = res+i
  }
```

will become

```

   #pragma omp task in_reduction(+:res) if(0)
   #pragma omp target map(res)
   for (int i=0; i<N; i++) {
     res = res+i
   }
```

Reviewed By: ABataev

Differential Revision: https://reviews.llvm.org/D125669
2022-06-27 10:36:46 -05:00