https://reviews.llvm.org/D84909
Patch adds two new GICombinerRules, one for G_INTTOPTR and one for
G_PTRTOINT. The G_INTTOPTR elides ptr2int(int2ptr(x)) to a copy of x, if
the cast is within the same address space. The G_PTRTOINT elides
int2ptr(ptr2int(x)) to a copy of x. Patch additionally adds new combiner
tests for the AArch64 target to test these new combiner rules.
Patch by mkitzan
It's possible to end up with a zext or something in the way of a G_CONSTANT,
even pre-legalization. This can happen with memsets.
e.g.
https://godbolt.org/z/Bjc8cw
To make sure we can catch these cases, use `getConstantVRegValWithLookThrough`
instead of `mi_match`.
Differential Revision: https://reviews.llvm.org/D81875
This implements the following combines:
((0-A) + B) -> B-A
(A + (0-B)) -> A-B
Porting over the basic algebraic combines from the DAGCombiner. There are
several combines which fold adds away into subtracts. This is just the simplest
one.
I noticed that add combines are some of the most commonly hit across CTMark,
(via print statements when they fire), so I'm porting over some of the obvious
ones.
This gives some minor code size improvements on CTMark at -O3 on AArch64.
Differential Revision: https://reviews.llvm.org/D77453
Summary:
Note to downstream target maintainers: this might silently change the semantics of your code if you override `TargetLowering::allowsMisalignedMemoryAccesses` without marking it override.
This patch is part of a series to introduce an Alignment type.
See this thread for context: http://lists.llvm.org/pipermail/llvm-dev/2019-July/133851.html
See this patch for the introduction of the type: https://reviews.llvm.org/D64790
Reviewers: courbet
Subscribers: hiraditya, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D81374
During legalization we can end up with extends of loads, which in the case of
zexts causes us to not hit tablegen imported patterns.
The caveat here is that we don't want anyext load forming, since some variants
are illegal. This change also prevents the combine from creating any illegal
loads.
Differential Revision: https://reviews.llvm.org/D80458
If we have a memory instruction (e.g. a load), we shouldn't combine it away in
some trivial combine.
It's possible that, say, a call lives between the instructions. This could
modify the value loaded, making the load instructions not safe to fold.
Differential Revision: https://reviews.llvm.org/D80053
(This patch is by Jessica, I'm just committing it on her behalf because I need
a post-legalizer combiner for something else).
This supersedes D77250, which did equivalent work in the selector. This can be
done pre-legalization or post-legalization. Post-legalization is more likely to
hit, since G_IMPLICIT_DEFs tend to appear during legalization. There's no reason
to not do it pre-legalization though-- if it can be caught earlier, great.
(I also think that it might be worth reimplementing D78769 using a
target-specific post-legalization combine too after thinking about it for a
while.)
Differential Revision: https://reviews.llvm.org/D78852
Summary:
Fix an issue which could result in ElideBrByInvertingCond or
CombineIndexedLoadStore being missed when debug info is present. In both
cases the fix is s/hasOneUse/hasOneNonDbgUse/.
Reviewers: aemerson, dsanders
Subscribers: hiraditya, aprantl, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D78254
Summary:
This fixes several issues where the presence of debug instructions could
disable certain combines, due to dominance queries finding uses/defs that
don't actually exist.
Reviewers: dsanders, fhahn, paquette, aemerson
Subscribers: hiraditya, arphaman, aprantl, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D78253
When we have
```
a = G_OR x, x
```
or
```
b = G_AND y, y
```
We can drop the G_OR/G_AND and just use x/y respectively.
Also update arm64-fallback.ll because there was an or in there which hits this
transformation.
Differential Revision: https://reviews.llvm.org/D77105
Implement identity combines for operations like the following:
```
%a = G_SUB %b, 0
```
This can just be replaced with %b.
Over CTMark, this gives some minor size improvements at -O3.
Differential Revision: https://reviews.llvm.org/D76640
When we see this:
```
%a = COPY $physreg
...
SOMETHING implicit-def $physreg
...
%b = COPY $physreg
```
The two copies are not equivalent, and so we shouldn't perform any folding
on them.
When we have two instructions which use a physical register check that they
define the same virtual register(s) as well.
e.g., if we run into this case
```
%a = COPY $physreg
...
%b = COPY %a
```
we can say that the two copies are the same, and can be folded.
Differential Revision: https://reviews.llvm.org/D76890
Summary:
This is patch is part of a series to introduce an Alignment type.
See this thread for context: http://lists.llvm.org/pipermail/llvm-dev/2019-July/133851.html
See this patch for the introduction of the type: https://reviews.llvm.org/D64790
Reviewers: courbet
Subscribers: arsenm, dschuff, sdardis, nemanjai, jvesely, nhaehnle, sbc100, jgravelle-google, hiraditya, aheejin, kbarton, jrtc27, atanasyan, jfb, kerbowa, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D76925
When we find something like this:
```
%a:_(s32) = G_SOMETHING ...
...
%select:_(s32) = G_SELECT %cond(s1), %a, %a
```
We can remove the select and just replace it entirely with `%a` because it's
always going to result in `%a`.
Same if we have
```
%select:_(s32) = G_SELECT %cond(s1), %a, %b
```
where we can deduce that `%a == %b`.
This implements the following cases:
- `%select:_(s32) = G_SELECT %cond(s1), %a, %a` -> `%a`
- `%select:_(s32) = G_SELECT %cond(s1), %a, %some_copy_from_a` -> `%a`
- `%select:_(s32) = G_SELECT %cond(s1), %a, %b` -> `%a` when `%a` and `%b`
are defined by identical instructions
This gives a few minor code size improvements on CTMark at -O3 for AArch64.
Differential Revision: https://reviews.llvm.org/D76523
Port over the following:
- shuffle undef, undef, any_mask -> undef
- shuffle anything, anything, undef_mask -> undef
This sort of thing shows up a lot when you try to bugpoint code containing
shufflevector.
Differential Revision: https://reviews.llvm.org/D76382
This ports some combines from DAGCombiner.cpp which perform some trivial
transformations on instructions with undef operands.
Not having these can make it extremely annoying to find out where we differ
from SelectionDAG by looking at existing lit tests. Without them, we tend to
produce pretty bad code generation when we run into instructions which use
undef operands.
Also remove the nonpow2_store_narrowing testcase from arm64-fallback.ll, since
we no longer fall back on the add.
Differential Revision: https://reviews.llvm.org/D76339
Produce an unmerge to a narrower type and introduce a narrower shift
if needed. I wasn't sure if there was a better way to parameterize the
target's preferred shift type for the GICombineRule, so manually call
the combine helper.
Like COPY instructions explained in D70616, we don't check the constraints
when combining G_UNMERGE_VALUES. Use the same logic used in D70616 to check
if registers can be replaced, or a COPY instruction needs to be built.
https://reviews.llvm.org/D70564
Summary: This patch introduces an API for MemOp in order to simplify and tighten the client code.
Reviewers: courbet
Subscribers: arsenm, nemanjai, jvesely, nhaehnle, hiraditya, kbarton, jsji, kerbowa, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D73964
Summary: This is a first step before changing the types to llvm::Align and introduce functions to ease client code.
Reviewers: courbet
Subscribers: arsenm, sdardis, nemanjai, jvesely, nhaehnle, hiraditya, kbarton, jrtc27, atanasyan, jsji, kerbowa, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D73785
For pow2 constants we should use G_SHL for pattern matching (and perf)
purposes later.
Vector support not yet implemented.
Differential Revision: https://reviews.llvm.org/D73659
We're planning to remove the shufflemask operand from ShuffleVectorInst
(D72467); fix GlobalISel so it doesn't depend on that Constant.
The change to prelegalizercombiner-shuffle-vector.mir happens because
the input contains a literal "-1" in the mask (so the parser/verifier
weren't really handling it properly). We now treat it as equivalent to
"undef" in all contexts.
Differential Revision: https://reviews.llvm.org/D72663
Summary:
When combining COPY instructions, we were replacing the destination registers
with the source register without checking register constraints. This patch adds
a simple logic to check if the constraints match before replacing registers.
Reviewers: qcolombet, aditya_nandakumar, aemerson, paquette, dsanders, Petar.Avramovic
Reviewed By: aditya_nandakumar
Subscribers: rovka, hiraditya, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D70616
LLVM IR of 1-element vectors get lower into scalar in GISel. As a
result, shuffle vector may also produce a scalar.
This patch teaches the shuffle combiner how to deal with scalars when
they are in the destination type of a shuffle vector.
For now, we just support the easy case where this can be lowered to
a plain copy. For other cases, we leave the shuffle vector as is.
This type of IR are seen in O0 pipelines. E.g., as produced with
SingleSource/UnitTests/Vector/AArch64/aarch64_neon_intrinsics.c.
rdar://problem/57198904
Summary:
G_GEP is rather poorly named. It's a simple pointer+scalar addition and
doesn't support any of the complexities of getelementptr. I therefore
propose that we rename it. There's a G_PTR_MASK so let's follow that
convention and go with G_PTR_ADD
Reviewers: volkan, aditya_nandakumar, bogner, rovka, arsenm
Subscribers: sdardis, jvesely, wdng, nhaehnle, hiraditya, jrtc27, atanasyan, arphaman, Petar.Avramovic, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D69734
Teach the combiner helper how to replace shuffle_vector of scalars
into build_vector.
I am not particularly happy about having to add this combine, but we
currently get those from <1 x iN> from the IR.
Bonus: This fixes an assert in the shuffle_vector combines since before
this patch, we were expecting vector types.
Teach the CombinerHelper how to turn shuffle_vectors, that
concatenate vectors, into concat_vectors and add this combine
to the AArch64 pre-legalizer combiner.
Differential Revision: https://reviews.llvm.org/D69149
llvm-svn: 375452
Teach the combiner helper how to flatten concat_vectors of build_vectors
into a build_vector.
Add this combine as part of AArch64 pre-legalizer combiner.
Differential Revision: https://reviews.llvm.org/D69071
llvm-svn: 375066
Summary:
This is just moving the existing C++ code around and will be NFC w.r.t
AArch64. Renamed 'CombineBr' to something more descriptive
('ElideByByInvertingCond') at the same time.
The remaining combines in AArch64PreLegalizeCombiner require features that
aren't implemented at this point and will be hoisted as they are added.
Depends on D68424
Reviewers: bogner, volkan
Subscribers: kristof.beyls, hiraditya, Petar.Avramovic, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D68426
llvm-svn: 375057
