This reverts commit d8f57105010cc7e78026e511d5def873fc91e0e7.
Original Commit:
Author: Haicheng Wu <haicheng@codeaurora.org>
Date: Sun Feb 18 13:51:33 2018 +0000
[AArch64] Coalesce Copy Zero during instruction selection
Add special case for copy of zero to avoid a double copy.
Differential Revision: https://reviews.llvm.org/D36104
Author's intention is to remove a BB that has one mov instruction. In
order to do that, d8f571050 pessmizes MachineSinking by introducing a
copy, such that mov instruction is NOT moved to the BB. Optimization
downstream gets rid of the BB with only mov instruction. This works well
if we have only one fall through branch as there is only one "extra"
mov instruction.
If we have multiple fall throughs, we will have a lot of redundant movs.
In such a case, it's better to have this BB which has one mov instruction.
This is causing degradation in jpeg, fft and other codebases. I believe
if we want to remove a BB with only one branch instruction, we should not
pessimize Machine Sinking at all, and find some other solution.
llvm-svn: 335251
Summary: This patch originated from D46562 and is a proper subset, with some issues addressed.
Reviewers: spatel, hfinkel, wristow, arsenm, javed.absar
Reviewed By: spatel
Subscribers: wdng, nhaehnle
Differential Revision: https://reviews.llvm.org/D47909
llvm-svn: 334996
Summary: This patch originated from D47388 and is a proper subset of the originating changes, containing only the fmf optimization guard extensions.
Reviewers: spatel, hfinkel, wristow, arsenm, javed.absar, rampitec, nhaehnle, nemanjai
Reviewed By: rampitec, nhaehnle
Subscribers: tpr, nemanjai, wdng
Differential Revision: https://reviews.llvm.org/D47918
llvm-svn: 334876
This is r334750 (which was reverted in r334754) with a fix for an
uninitialized variable that was caught by msan.
Original commit message:
> If a copy bundle happens to involve overlapping registers, we can end
> up with emitting the copies in an order that ends up clobbering some
> of the subregisters. Since instructions in the copy bundle
> semantically happen at the same time, this is incorrect and we need to
> make sure we order the copies such that this doesn't happen.
llvm-svn: 334756
If a copy bundle happens to involve overlapping registers, we can end
up with emitting the copies in an order that ends up clobbering some
of the subregisters. Since instructions in the copy bundle
semantically happen at the same time, this is incorrect and we need to
make sure we order the copies such that this doesn't happen.
Differential Revision: https://reviews.llvm.org/D48154
llvm-svn: 334750
We're constant folding here, so we shouldn't check uses. This matches
the IR optimizer behavior.
The x86 test shows the expected win. The AArch64 test shows something
else. This only seems to happen if the "generic" AArch64 CPU model is
used by MachineCombiner, so I'll file a bug report to follow-up.
llvm-svn: 334608
Register x20 is a callee-saved register which may be used for other
purposes in certain contexts, for example to hold special variables
within the kernel. This change adds support for reserving this register
both to frontend and backend to make this register usable for these
purposes.
Differential Revision: https://reviews.llvm.org/D46552
llvm-svn: 334531
Apparently, MachineInstr class definition as well as pretty much all of
the machine passes assume that the only kind of MachineInstr's operands
that is variadic for variadic opcodes is explicit non-definitions.
In particular, this assumption is made by MachineInstr::defs(), uses(),
and explicit_uses() methods, as well as by MachineCSE pass.
The assumption is incorrect judging from at least TableGen backend
implementation, that recognizes variable_ops in OutOperandList, and the
very existence of G_UNMERGE_VALUES generic opcode, or ARM load multiple
instructions, all of which have variadic defs.
In particular, MachineCSE pass breaks MIR with CSE'able G_UNMERGE_VALUES
instructions in it.
This commit implements MachineInstr::getNumExplicitDefs() similar to
pre-existing MachineInstr::getNumExplicitOperands(), fixes
MachineInstr::defs(), uses(), and explicit_uses(), and fixes MachineCSE
pass.
As the issue addressed seems to affect only machine passes that could be
ran mid-GlobalISel pipeline at the moment, the other passes aren't fixed
by this commit, like MachineLICM: that could be done on per-pass basis
when (if ever) they get adopted for GlobalISel.
Reviewed By: arsenm
Differential Revision: https://reviews.llvm.org/D45640
llvm-svn: 334520
Summary:
In D47428, i propose to choose the `~(-(1 << nbits))` as the canonical form of low-bit-mask formation.
As it is seen from these tests, there is a reason for that.
AArch64 currently better handles `~(-(1 << nbits))`, but not the more traditional `(1 << nbits) - 1` (sic!).
The other way around for X86.
It would be much better to canonicalize.
It would seem that there is too much tests, but this is most of all the auto-generated possible variants
of C code that one would expect for BZHI to be formed, and then manually cleaned up a bit.
So this should be pretty representable, which somewhat good coverage...
Related links:
https://bugs.llvm.org/show_bug.cgi?id=36419https://bugs.llvm.org/show_bug.cgi?id=37603https://bugs.llvm.org/show_bug.cgi?id=37610https://rise4fun.com/Alive/idM
Reviewers: javed.absar, craig.topper, RKSimon, spatel
Reviewed By: RKSimon
Subscribers: kristof.beyls, llvm-commits, RKSimon, craig.topper, spatel
Differential Revision: https://reviews.llvm.org/D47452
llvm-svn: 334124
If no alignment is set, the abi/preferred alignment of structs will be
used which may be higher than required. This can lead to extra padding
and in the end an increase in data size.
Differential Revision: https://reviews.llvm.org/D47633
llvm-svn: 334099
Start by emitting remarks for very basic unsupported cases such as
irreducible CFGs and EHFunclets. The end goal is to be able to cover all
the cases where we give up with an explanation.
llvm-svn: 333972
Before we were relying on the any extend of the s1 to s32, but
for AAPCS we need to zero-extend it to at least s8.
Fixes PR36719
Differential Revision: https://reviews.llvm.org/D47425
llvm-svn: 333747
This is to make it clear what kind of bugs the LegalizerInfo::verifier
is able to catch and test its output
Reviewers: aemerson, qcolombet
Reviewed By: aemerson
Differential Revision: https://reviews.llvm.org/D46338
llvm-svn: 333597
As suggested in https://bugs.llvm.org/show_bug.cgi?id=32384#c1, this change
makes the inlining of `memset()` and `memcpy()` more aggressive when
compiling for speed. The tuning remains the same when optimizing for size.
Patch by: Sebastian Pop <s.pop@samsung.com>
Evandro Menezes <e.menezes@samsung.com>
Differential revision: https://reviews.llvm.org/D45098
llvm-svn: 333429
The existing code has three different ways to try to lower a 64-bit
immediate to the sequence ORR+MOVK. The result is messy: it misses
some possible sequences, and the order of the checks means we sometimes
emit two MOVKs when we only need one.
Instead, just use a simple loop to try all possible two-instruction
ORR+MOVK sequences.
Differential Revision: https://reviews.llvm.org/D47176
llvm-svn: 333218
When we're outlining a sequence that ends in a call, we can save up to
three instructions in the outlined function by turning the call into
a tail-call. I refer to this as thunk outlining because the resulting
outlined function looks like a thunk; suggestions welcome for a better
name.
In addition to making the outlined function shorter, thunk outlining
allows outlining calls which would otherwise be illegal to outline:
we don't need to save/restore LR, so we don't need to prove anything
about the stack access patterns of the callee.
To make this work effectively, I also added
MachineOutlinerInstrType::LegalTerminator to the generic MachineOutliner
code; this allows treating an arbitrary instruction as a terminator in
the suffix tree.
Differential Revision: https://reviews.llvm.org/D47173
llvm-svn: 333015
This is the FP sibling of D43141 with the corresponding IR change in rL327212.
We can't propagate undef here because if a variable operand is a NaN, these
binops must propagate NaN. Neither global nor node-level fast-math makes a
difference. If we have 'nnan', I think later folds can turn the NaN into undef.
The tests in X86/fp-undef.ll are meant to be the definitive verification for
these folds - everything reduces identically now.
The other test changes are collateral damage. They may need to be altered to
preserve their intent.
Differential Revision: https://reviews.llvm.org/D47026
llvm-svn: 332920
Summary:
This **appears** to be the last missing piece for the masked merge pattern handling in the backend.
This is [[ https://bugs.llvm.org/show_bug.cgi?id=37104 | PR37104 ]].
[[ https://bugs.llvm.org/show_bug.cgi?id=6773 | PR6773 ]] will introduce an IR canonicalization that is likely bad for the end assembly.
Previously, `andps`+`andnps` / `bsl` would be generated. (see `@out`)
Now, they would no longer be generated (see `@in`), and we need to make sure that they are generated.
Differential Revision: https://reviews.llvm.org/D46528
llvm-svn: 332904
Counting the number of instructions is both unintuitive and inaccurate.
On AArch64, this only affects the generated remarks and certain rare
pseudo-instructions, but it will have a bigger impact on other targets.
Differential Revision: https://reviews.llvm.org/D46921
llvm-svn: 332685
We need to clean up the DAG floating-point undef logic.
This process is similar to how we handled integer undef
logic in D43141.
And as we did there, I'm trying to reduce the patch by
changing tests that would probably become meaningless
once we correct FP undef folding.
Follow-up to:
https://reviews.llvm.org/rL332534
...because that change wasn't enough.
llvm-svn: 332636
We need to clean up the DAG floating-point undef logic.
This process is similar to how we handled integer undef
logic in D43141.
And as we did there, I'm trying to reduce the patch by
changing tests that would probably become meaningless
once we correct FP undef folding.
llvm-svn: 332534
This breaks the code which saves and restores LR, so we can't outline
without doing something more complicated for stack adjustment.
Found by inspection; we get lucky in most cases because getMemOpInfo
only handles STRWpost, not any other pre/post-increment forms. But it
hits a couple of artificial testcases in the tree.
Differential Revision: https://reviews.llvm.org/D46920
llvm-svn: 332529
The cost computation assumes we do this correctly, but the actual
lowering was wrong.
Differential Revision: https://reviews.llvm.org/D46923
llvm-svn: 332514
Keep loads and stores together (target defines how many loads
and stores to gang up), such that it will help in pairing
and vectorization.
Differential Revision https://reviews.llvm.org/D46477
llvm-svn: 332482
We currently handle all aggregates by creating one large LLT, and letting the
legalizer deal with splitting them up. However using this approach means that
we can't support big endian code correctly.
This patch changes the way that the IRTranslator deals with aggregate values,
by splitting them up into their constituent element values. To do this, parts
of the translator need to be modified to deal with multiple VRegs for a single
Value.
A new Value to VReg mapper is introduced to help keep compile time under
control, currently there is no measurable impact on CTMark despite the extra
code being generated in some cases.
Patch is based on the original work of Tim Northover.
Differential Revision: https://reviews.llvm.org/D46018
llvm-svn: 332449
This patch re-introduces the "S" inline assembler constraint. This matches
an absolute symbolic address or a label reference. The primary use case is
asm("adrp %0, %1\n\t"
"add %0, %0, :lo12:%1" : "=r"(addr) : "S"(&var));
I say re-introduces as it seems like "S" was implemented in the original
AArch64 backend, but it looks like it wasn't carried forward to the merged
backend. The original implementation had A and L modifiers that could be
used to print ":lo12:" to the string. It looks like gcc doesn't use these
and :lo12: is expected to be written in the inline assembly string so I've
not implemented A and L. Clang already supports the S modifier.
Fixes PR37180
Differential Revision: https://reviews.llvm.org/D46745
llvm-svn: 332444
It doesn't matter much this late in the pipeline, but one place that
does check for it is the function alignment code.
Differential Revision: https://reviews.llvm.org/D46373
llvm-svn: 332415
When storing the 0th lane of a vector, use a simpler and usually more
efficient scalar store instead. In this case, also using the unscaled
offset.
Differential revision: https://reviews.llvm.org/D46762
llvm-svn: 332394
The test case added in r332265 had incomplete livein information which
was caught by the EXPENSIVE_CHECKS bot. Fix the livein information and
add -verify-machineinstrs to the test case.
llvm-svn: 332367
This is a simple hack based on what's proposed in D37686, but we can extend it if needed in follow-ups.
It gets us most of the FMF functionality that we want without adding any state bits to the flags. It
also intentionally leaves out non-FMF flags (nsw, etc) to minimize the patch.
It should provide a superset of the functionality from D46563 - the extra tests show propagation and
codegen diffs for fcmp, vecreduce, and FP libcalls.
The PPC log2() test shows the limits of this most basic approach - we only applied 'afn' to the last
node created for the call. AFAIK, there aren't any libcall optimizations based on the flags currently,
so that shouldn't make any difference.
Differential Revision: https://reviews.llvm.org/D46854
llvm-svn: 332358
Summary:
The BranchFolding pass is currently missing opportunities to hoist
common code if the hoisted-to block contains a single conditional branch
that has register uses. This occurs somewhat frequently on AArch64 with
CBZ/TBZ opcodes.
This change also eliminates some code differences when debug info is
present since the presence of e.g. DBG_VALUE instructions in the
hoisted-to block can enable hoisting that wouldn't have occurred without
them.
Reviewers: MatzeB, rnk, kparzysz, twoh, aprantl, javed.absar
Subscribers: kristof.beyls, JDevlieghere, mcrosier, llvm-commits
Differential Revision: https://reviews.llvm.org/D46324
llvm-svn: 332265
When storing the 0th lane of a vector, use a simpler and usually more efficient scalar store instead.
Differential revision: https://reviews.llvm.org/D46655
llvm-svn: 332251
This teaches tryToFoldExtOfLoad to set the right location on a
newly-created extload. With that in place, the logic for performing a
certain ([s|z]ext (load ...)) combine becomes identical for sexts and
zexts, and we can get rid of one copy of the logic.
The test case churn is due to dependencies on IROrders inherited from
the wrong SDLoc.
Part of: llvm.org/PR37262
Differential Revision: https://reviews.llvm.org/D46158
llvm-svn: 332118
Summary:
performPostLD1Combine in AArch64ISelLowering looks for vector
insert_vector_elt of a loaded value which it can optimize into a single
LD1LANE instruction. The code checking for the pattern was not checking
if the lane index was a constant which could cause two problems:
- an assert when lowering the LD1LANE ISD node since it assumes an
constant operand
- an assert in isel if the lane index value depends on the
post-incremented base register
Both of these issues are avoided by simply checking that the lane index
is a constant.
Fixes bug 35822.
Reviewers: t.p.northover, javed.absar
Subscribers: rengolin, kristof.beyls, mcrosier, llvm-commits
Differential Revision: https://reviews.llvm.org/D46591
llvm-svn: 332103
The second source operand of G_SHL, G_ASHR, and G_LSHR must preserve its
value as a (small) unsigned integer, therefore its incorrect to widen it
in any way but by zero extending it.
G_SHL was using G_ANYEXT and G_ASHR - G_SEXT (which is correct for their
destination and first source operands, but not the "number of bits to
shift" operand).
Generally, shifts aren't as similar to regular binary operations as it
might seem, for instance, they aren't commutative nor associative and
the second source operand usually requires a special treatment.
Reviewers: bogner, javed.absar, aivchenk, rovka
Reviewed By: bogner
Subscribers: igorb, kristof.beyls, llvm-commits
Differential Revision: https://reviews.llvm.org/D46413
llvm-svn: 331926
Aditya Nandakumar