Debug info is currently preventing VPT block creation, leading to
different codegen. This patch attempts to skip any debug instructions
during vpt block creation, making sure they do not interfere.
Differential Revision: https://reviews.llvm.org/D103610
We remove VPNOT instructions in VPT blocks as we create them, turning
them into else predicates. We don't remove the dead instructions until
after the block has been created though. Because the VPNOT will have
killed the vpr register it used, this makes finalizeBundle add internal
flags to the vpr uses of any instructions after the VPNOT. These
incorrect flags can then confuse what is alive and what is not, leading
to machine verifier problems.
This patch removes them earlier instead, before the bundle is finalized
so that kill flags remain valid.
Differential Revision: https://reviews.llvm.org/D92227
This was accidentally using the same name for two different variables in
the same line. Whilst it seems to work for some compilers, others have
trouble and it is probably not a fantastic idea.
When we fold a VCMP into a VPST instruction any kill flags between the
old VCMP position and the new insertion point need to be removed, in
order to keep the verifier happy.
Differential Revision: https://reviews.llvm.org/D90964
getARMVPTBlockMask was an outdated function that only handled basic
block masks: T, TT, TTT and TTTT. This worked fine before the MVE
VPT Block Insertion Pass improvements as it was the only kind of
masks that it could generate, but now it can generate more complex
masks that uses E predicates, so it's dangerous to use that function
to calculate VPT/VPST block masks.
I replaced it with 2 different functions:
- expandPredBlockMask, in ARMBaseInfo. This adds an "E" or "T" at
the end of an existing PredBlockMask.
- recomputeVPTBlockMask, in Thumb2InstrInfo. This takes an iterator
to a VPT/VPST instruction and recomputes its block mask by looking
at the predicated instructions that follows it. This should be
used to recompute a block mask after removing/adding a predicated
instruction to the block.
The expandPredBlockMask function is pretty much imported from the MVE
VPT Blocks pass.
I had to change the ARMLowOverheadLoops and MVEVPTBlocks passes as well
so they could use these new functions.
Differential Revision: https://reviews.llvm.org/D78201
The pass was incorrectly reverting back to a "T" when something wrote
to VPR inside a "E" block. This is not the correct behaviour, the
predicate should stay the same.
Differential Revision: https://reviews.llvm.org/D77798
This allows the MVE VPT Block insertion pass to remove VPNOTs in
order to create more complex VPT blocks such as TE, TEET, TETE, etc.
Differential Revision: https://reviews.llvm.org/D75993
This reverts commit e34801c8e6df and the followup due to multiple
problems.
I've tried to keep the tests and RDA parts where possible, as those
still seem useful.
Fix a missing and broken test: 2 VPT blocks predicated on the same VCMP
instruction that can be folded. The problem was that for each VPT block, we
record the predicate statements with a list, but the same instruction was added
twice. Thus, we were running in an assert trying to remove the same instruction
twice. To avoid this the instructions are now recorded with a set.
Differential Revision: https://reviews.llvm.org/D72699
This is a recommit of D71330, but with a few things fixed and changed:
1) ReachingDefAnalysis: this was not running with optnone as it was checking
skipFunction(), which other analysis passes don't do. I guess this is a
copy-paste from a codegen pass.
2) VPTBlockPass: here I've added skipFunction(), because like most/all
optimisations, we don't want to run this with optnone.
This fixes the issues with the initial/previous commit: the VPTBlockPass was
running with optnone, but ReachingDefAnalysis wasn't, and so VPTBlockPass was
crashing querying ReachingDefAnalysis.
I've added test case mve-vpt-block-optnone.mir to check that we don't run
VPTBlock with optnone.
Differential Revision: https://reviews.llvm.org/D71470
Record the discovered VPT blocks while checking for validity and, for
now, only handle blocks that begin with VPST and not VPT. We're now
allowing more than one instruction to define vpr, but each block must
somehow be predicated using the vctp. This leaves us with several
scenarios which need fixing up:
1) A VPT block with is only predicated by the vctp and has no
internal vpr defs.
2) A VPT block which is only predicated by the vctp but has an
internal vpr def.
3) A VPT block which is predicated upon the vctp as well as another
vpr def.
4) A VPT block which is not predicated upon a vctp, but contains it
and all instructions within the block are predicated upon in.
The changes needed are, for:
1) The easy one, just remove the vpst and unpredicate the
instructions in the block.
2) Remove the vpst and unpredicate the instructions up to the
internal vpr def. Need insert a new vpst to predicate the
remaining instructions.
3) No nothing.
4) The vctp will be inside a vpt and the instruction will be removed,
so adjust the size of the mask on the vpst.
Differential Revision: https://reviews.llvm.org/D71107
In ARMLowOverheadLoops.cpp, MVETailPredication.cpp, and MVEVPTBlock.cpp we have
quite a few helper functions all looking at the opcodes of MVE instructions.
This moves all these utility functions to ARMBaseInstrInfo.
Diferential Revision: https://reviews.llvm.org/D71426
This reverts commit 9468e3334ba54fbb1b209aaec662d7375451fa1f.
There's a test that doesn't like this change. The RDA analysis
gets invalided by changes in the block, which is not taken into
account. Revert while I work on a fix for this.
This adds ReachingDefAnalysis (RDA) to the VPTBlock pass, so that we can
reimplement findVCMPToFoldIntoVPS with just a few calls to RDA.
Differential Revision: https://reviews.llvm.org/D71330
MVE has VPT instructions, which perform the duties of both a VCMP and a VPST in
a single instruction, performing the compare and starting the VPT block in one.
This teaches the MVEVPTBlockPass to fold them, searching back through the
basicblock for a valid VCMP and creating the VPT from its operands.
There are some changes to the VPT instructions to accommodate this, altering
the order of the operands to match the VCMP better, and changing P0 register
defs to be VPR defs, as is used in other places.
Differential Revision: https://reviews.llvm.org/D66577
llvm-svn: 371982
This attempts to just fix the creation of VPT blocks, fixing up the iterating,
which instructions are considered in the bundle, and making sure that we do not
overrun the end of the block.
Differential Revision: https://reviews.llvm.org/D67219
llvm-svn: 371064
This just pulls the MVEVPTBlockPass into a separate file, as opposed to being
wrapped up in Thumb2ITBlockPass.
Differential revision: https://reviews.llvm.org/D66579
llvm-svn: 370187
