9 Commits

Author SHA1 Message Date
Chen Zheng
85edf1fc70 [PowerPC] remove the ctr clobbers check related to TLS access
Dynamic tls access model will be lowered to MI which clobbers CTR in
the loop in ISEL(ADDItlsgdLADDR) and post-isel CTR loop pass will revert
the loop to a normal compare + branch form.

So no need to add this clobber check in hardware loop insertion pass now.

Reviewed By: nemanjai

Differential revision: https://reviews.llvm.org/D140367
2023-01-05 21:23:29 -05:00
Chen Zheng
dd0edc876c [PowerPC][NFC] add an option to keep the test point
Passes before hardware loop insertion change the loop to a form which
is not a hardware loop candidate (return early before checking the ctr clobbers).
And the PHI in the loop exit block is also optimized away. This breaks the
previous test point when the case was committed. Fixing this by running this
case just before hardware loop insertion pass.

Reviewed By: nemanjai

Differential revision: https://reviews.llvm.org/D140366
2023-01-05 21:18:53 -05:00
Roman Lebedev
3a8e009f97
Revert "Reland "[SimplifyCFG] FoldBranchToCommonDest(): deal with mismatched IV's in PHI's in common successor block""
One of these two changes is exposing (or causing) some more miscompiles.
A reproducer is in progress, so reverting until resolved.

This reverts commit 428f36401b1b695fd501ebfdc8773bed8ced8d4e.
2022-12-20 18:36:42 +03:00
Roman Lebedev
428f36401b
Reland "[SimplifyCFG] FoldBranchToCommonDest(): deal with mismatched IV's in PHI's in common successor block"
This reverts commit 37b8f09a4b61bf9bf9d0b9017d790c8b82be2e17,
and returns commit 1bd0b82e508d049efdb07f4f8a342f35818df341.
The miscompile was in InstCombine, and it has been addressed.

This tries to approach the problem noted by @arsenm:
terrible codegen for `__builtin_fpclassify()`:
https://godbolt.org/z/388zqdE37

Just because the PHI in the common successor happens to have different
incoming values for these two blocks, doesn't mean we have to give up.
It's quite easy to deal with this, we just need to produce a select:
https://alive2.llvm.org/ce/z/000srb

Now, the cost model for this transform is rather overly strict,
so this will basically never fire. We tally all (over all preds)
the selects needed to the NumBonusInsts

Differential Revision: https://reviews.llvm.org/D139275
2022-12-17 05:18:54 +03:00
Alexander Kornienko
37b8f09a4b Revert "[SimplifyCFG] FoldBranchToCommonDest(): deal with mismatched IV's in PHI's in common successor block"
This reverts commit 1bd0b82e508d049efdb07f4f8a342f35818df341, since it leads to
miscompiles. See https://reviews.llvm.org/D139275#3993229 and
https://reviews.llvm.org/D139275#4001580.
2022-12-16 17:23:35 +01:00
Roman Lebedev
1bd0b82e50
[SimplifyCFG] FoldBranchToCommonDest(): deal with mismatched IV's in PHI's in common successor block
This tries to approach the problem noted by @arsenm:
terrible codegen for `__builtin_fpclassify()`:
https://godbolt.org/z/388zqdE37

Just because the PHI in the common successor happens to have different
incoming values for these two blocks, doesn't mean we have to give up.
It's quite easy to deal with this, we just need to produce a select:
https://alive2.llvm.org/ce/z/000srb

Now, the cost model for this transform is rather overly strict,
so this will basically never fire. We tally all (over all preds)
the selects needed to the NumBonusInsts

Differential Revision: https://reviews.llvm.org/D139275
2022-12-12 18:20:03 +03:00
Chen Zheng
eb7d16ea25 [PowerPC] make expensive mflr be away from its user in the function prologue
mflr is kind of expensive on Power version smaller than 10, so we should
schedule the store for the mflr's def away from mflr.

In epilogue, the expensive mtlr has no user for its def, so it doesn't
matter that the load and the mtlr are back-to-back.

Reviewed By: RolandF

Differential Revision: https://reviews.llvm.org/D137423
2022-11-14 21:14:20 -05:00
Kai Nacke
5403c59c60 [PPC] Opaque pointer migration, part 2.
The LIT test cases were migrated with the script provided by
Nikita Popov. Due to the size of the change it is split into
several parts.

Reviewed By: nemanja, nikic

Differential Revision: https://reviews.llvm.org/D135474
2022-10-11 17:24:06 +00:00
Nemanja Ivanovic
4f568fbd21 [PowerPC] Do not emit HW loop when TLS var accessed in PHI of loop exit
If any PHI nodes in loop exit blocks have incoming values from the
loop that are accesses of TLS variables with local dynamic or general
dynamic TLS model, the address will be computed inside the loop. Since
this includes a call to __tls_get_addr, this will in turn cause the
CTR loops verifier to complain.
Disable CTR loops in such cases.

Fixes: https://bugs.llvm.org/show_bug.cgi?id=48527
2020-12-28 20:36:16 -06:00