This was causing a machine verifier failure on the test suite.
Make sure that we don't end up with a weird register class here.
Failure for reference:
*** Bad machine code: Illegal virtual register for instruction ***
- function: check_constrain
- basic block: %bb.1 (0x7f8b70839f80)
- instruction: early-clobber %6:gpr64, early-clobber %7:gpr64sp =
JumpTableDest32 %5:gpr64, %1:gpr64sp, %jump-table.0
- operand 3: %1:gpr64sp
Expected a GPR64 register, but got a GPR64sp register
Differential Revision: https://reviews.llvm.org/D77349
This reverts commit b3297ef051.
This change is incorrect. The current semantic of null in the IR is a
pointer with the bitvalue 0. It is not a cast from an integer 0, so
this should preserve the pointer type.
Previously for any copy from a register bigger than the destination:
Copied to a same-sized register in the destination register bank.
Subregister copy of that to the destination.
This fails for copies from 128-bit FPRs to GPRs because the GPR register bank
can't accomodate 128-bit values.
Instead of special-casing such copies to perform the truncation beforehand in
the source register bank, generalize this:
a) Perform a subregister copy straight from source register whenever possible.
This results in shorter MIR and fixes the above problem.
b) Perform a full copy to target bank and then do a subregister copy only if
source bank can't support target's size. E.g. GPR to 8-bit FPR copy.
Patch by Raul Tambre (tambre)!
Differential Revision: https://reviews.llvm.org/D75421
Since all types <32b on gpr end up being assigned gpr32 regclasses, we can end
up with PHIs here which try to select between a gpr32 and an fpr16. Ideally RBS
shouldn't be selecting heterogenous regbanks for operands if possible, but we
still need to be able to deal with it here.
To fix this, if we have a gpr-bank operand < 32b in size and at least one other
operand is on the fpr bank, then we add cross-bank copies to homogenize the
operand banks. For simplicity the bank that we choose to settle on is whatever
bank the def operand has. For example:
%endbb:
%dst:gpr(s16) = G_PHI %in1:gpr(s16), %bb1, %in2:fpr(s16), %bb2
=>
%bb2:
...
%in2_copy:gpr(s16) = COPY %in2:fpr(s16)
...
%endbb:
%dst:gpr(s16) = G_PHI %in1:gpr(s16), %bb1, %in2_copy:gpr(s16), %bb2
Differential Revision: https://reviews.llvm.org/D75086
When we have to widen to a 64-bit register, we have to emit a SUBREG_TO_REG.
Add a general-purpose widening helpe which emits the correct SUBREG_TO_REG
instruction based off of a desired size and add a testcase.
Also remove some asserts which are technically incorrect in `emitTestBit`.
- p0 doesn't count as a scalar type, so we need to check `!Ty.isVector()`
instead
- Whenever we have a s1, the Size/Bit checks are too conservative, so just
remove them
Replace these asserts with less conservative ones where applicable.
Differential Revision: https://reviews.llvm.org/D74427
The issue in the previous commits was that we swap the LHS and RHS while
looking for the constant. In SLT/SGT, the constant must be on the RHS, or the
optimization is invalid.
Move the swapping logic after the check for the SLT/SGT case and update tests.
Original commits:
d78cefb160a373841407
This reverts commit a373841407.
It looks like this broke set_shadow_test.c, so I'm reverting until I can fix it.
I also reverted the SGT change because it's probably also broken.
When we have a G_BRCOND fed by a sgt compare against -1, we can just emit a TBZ.
This is similar to the code in `AArch64TargetLowering::LowerBR_CC`.
Also while we're here, properly scope the commutative constant check in
`selectCompareBranch`, since it sometimes would call
`getConstantVRegValWithLookThrough` twice.
Differential Revision: https://reviews.llvm.org/D74149
When we have a G_ICMP which checks SLT, and the comparison is against 0, we
can emit a TBNZ instead of a CBZ.
This lets us fold in things into the branch, which can provide some code size
savings.
This is similar to the case in `AArch64TargetLowering::LowerBR_CC`.
https://reviews.llvm.org/D74090
Factor it out into `emitTestBit` and add some asserts to the new function.
This will be useful for implementing TB(N)Z emission for SLT/SGT compares.
Differential Revision: https://reviews.llvm.org/D74080
Add support for walking through G_LSHR in `getTestBitReg`. Equivalent to the
code in `getTestBitOperand` in AArch64ISelLowering.
```
(tbz (lshr x, c), b) -> (tbz x, b+c) when b + c is < # bits in x
```
Differential Revision: https://reviews.llvm.org/D74077
contractCrossBankCopyIntoStore() finds the instruction defines the
source register and uses its output to replace the register. There are,
however, instructions that have multiple outputs, e.g. G_UNMERGE_VALUES.
Current implementation hardcodes to operand 0 and has no way of knowing
which output should be used.
This change adds another function to directly return the register that
is the source of the register and use that for folding.
This fixes https://bugs.llvm.org/show_bug.cgi?id=44783
Differential Revision: https://reviews.llvm.org/D74005
This implements walking over G_ASHR in the same way as `getTestBitOperand` in
AArch64ISelLowering.
```
(tbz (ashr x, c), b) -> (tbz x, b+c) or (tbz x, msb) if b+c is > # bits in x
```
Differential Revision: https://reviews.llvm.org/D73933
(1) The check needs to be on the 0th operand of whatever we're folding
(2) Checks for validity should happen before we change the bit
Fixes a bug which caused MultiSource/Applications/JM/lencod to fail at -O3.
Differential Revision: https://reviews.llvm.org/D74002
This ports the existing case for G_XOR from `getTestBitOperand` in
AArch64ISelLowering into GlobalISel.
The idea is to flip between TBZ and TBNZ while walking through G_XORs.
Let's say we have
```
tbz (xor x, c), b
```
Let's say the `b`-th bit in `c` is 1. Then
- If the `b`-th bit in `x` is 1, the `b`-th bit in `(xor x, c)` is 0.
- If the `b`-th bit in `x` is 0, then the `b`-th bit in `(xor x, c)` is 1.
So, then
```
tbz (xor x, c), b == tbnz x, b
```
Let's say the `b`-th bit in `c` is 0. Then
- If the `b`-th bit in `x` is 1, the `b`-th bit in `(xor x, c)` is 1.
- If the `b`-th bit in `x` is 0, then the `b`-th bit in `(xor x, c)` is 0.
So, then
```
tbz (xor x, c), b == tbz x, b
```
Differential Revision: https://reviews.llvm.org/D73929
This implements the following optimization:
```
(tbz (shl x, c), b) -> (tbz x, b-c)
```
Which appears in `getTestBitOperand` in AArch64ISelLowering.cpp.
If we test bit `b` of `shl x, c`, we can fold away the `shl` by looking `c` bits
to the right of `b` in `x` when this fits in the type. So, we can just test the
`b-c`th bit.
Differential Revision: https://reviews.llvm.org/D73924
Given
```
tb(n)z (and x, m), b
```
Where the `b`-th bit of `m` is 1,
```
tb(n)z (and x, m), b == tb(n)z x, b
```
So, we can walk past a `G_AND` in this case.
Also add test/CodeGen/AArch64/GlobalISel/opt-fold-and-tbz-tbnz.mir to test this.
Differential Revision: https://reviews.llvm.org/D73790
convertPtrAddToAdd improved overall code size and quality by a significant amount,
but on -O0 we generate some cross-class copies due to the fact that we emitted
G_PTRTOINT and G_INTTOPTR around the G_ADD. Unfortunately at -O0 we don't run any
register coalescing, so these cross class copies end up escaping as moves, and
we ended up regressing 3 benchmarks on CTMark (though still a winner overall).
This patch changes the lowering to instead directly emit the G_ADD into the
destination register, and then force changes the dest LLT to s64 from p0. This
should be ok, as all uses of the register should now be selected and therefore
the LLT doesn't matter for the users. It does however matter for the importer
patterns, which will fail to select a G_ADD if there's a p0 LLT.
I'm not able to get rid of the G_PTRTOINT on the source yet however. We can't
use the same trick of breaking the type system since that could break the
selection of the defining instruction. Thus with -O0 we still end up with a
cross class copy on source.
Code size improvements on -O0:
Program baseline new diff
test-suite :: CTMark/Bullet/bullet.test 965520 949164 -1.7%
test-suite...TMark/7zip/7zip-benchmark.test 1069456 1052600 -1.6%
test-suite...ark/tramp3d-v4/tramp3d-v4.test 1213692 1199804 -1.1%
test-suite...:: CTMark/sqlite3/sqlite3.test 421680 419736 -0.5%
test-suite...-typeset/consumer-typeset.test 837076 833380 -0.4%
test-suite :: CTMark/lencod/lencod.test 799712 796976 -0.3%
test-suite...:: CTMark/ClamAV/clamscan.test 688264 686132 -0.3%
test-suite :: CTMark/kimwitu++/kc.test 1002344 999648 -0.3%
test-suite...Mark/mafft/pairlocalalign.test 422296 421768 -0.1%
test-suite :: CTMark/SPASS/SPASS.test 656792 656532 -0.0%
Geomean difference -0.6%
Differential Revision: https://reviews.llvm.org/D73910
When you encounter a G_TRUNC, you are moving from a larger type to a smaller
type.
Asking for the i-th bit on a larger value is the same as asking for the i-th
bit on a smaller value.
So, we should always be able to walk through G_TRUNC when computing the bit
for a TB(N)Z.
Differential Revision: https://reviews.llvm.org/D73748
This is similar to the code in getTestBitOperand in AArch64ISelLowering. Instead
of implementing all of the TB(N)Z optimizations at once, this patch implements
the simplest case first. The way that this is set up should make it fairly easy
to add the rest as we go along.
The idea here is that after determining that we can use a TB(N)Z, we can
continue looking through instructions and perform further folding.
In this case, when we have a G_ZEXT or G_ANYEXT where the extended bits are not
used, we can fold it into the TB(N)Z.
Differential Revision: https://reviews.llvm.org/D73673
Found by inspection, but there's no test for this yet because G_PTR_ADD is
currently illegal for vectors. I'll add the test at a later time when the
legalizer support has landed.
This lowering tries to look for G_PTR_ADD instructions and then converts
them to a standard G_ADD with a COPY on the source, and G_INTTOPTR on the
result. This is ok for address space 0 on AArch64 as p0 can be treated as
s64.
The motivation behind this is to expose the add semantics to the imported
tablegen patterns. We shouldn't need to check for uses being loads/stores,
because the selector works bottom up, uses before defs. By the time we
end up trying to select a G_PTR_ADD, we should have already attempted to
fold this into addressing modes and were therefore unsuccessful.
This gives some performance and code size improvements across the board.
Differential Revision: https://reviews.llvm.org/D73673
When the bit is <= 32, we have to use the W register variant for TB(N)Z.
This is because of the way the instruction is encoded.
Differential Revision: https://reviews.llvm.org/D73660
When the G_BRCOND is fed by a eq or ne G_ICMP, it may be possible to fold a
G_AND into the branch by producing a tbnz/tbz instead.
This happens when
1. We have a ne/eq G_ICMP feeding into the G_BRCOND
2. The G_ICMP is a comparison against 0
3. One of the operands of the G_AND is a power of 2 constant
This is very similar to the code in AArch64TargetLowering::LowerBR_CC.
Add opt-and-tbnz-tbz to test this.
Differential Revision: https://reviews.llvm.org/D73573
It can still be beneficial to do the optimization if the result of the compare
is used by *another* select.
Differential Revision: https://reviews.llvm.org/D73511
When I cached this a long time ago it seems I forgot to remove the locally
declared variable of the same name in select(), so the caching wasn't having
any compile time benefit. Doh.
The code was originally ported from SelectionDAG, which does CSE behind the scenes
automatically. When copying the return address from LR live into the function, we
need to make sure to use the single copy on function entry. Any later copy from LR
could be using clobbered junk.
Implement this by caching the copy in the per-MF state in the selector.
Should hopefully fix the AArch64 sanitiser buildbot failure.
These intrinsics expand to a variable number of instructions so just like in
ISelLowering.cpp we use custom code to deal with them.
Committing Tim's original patch.
Differential Revision: https://reviews.llvm.org/D65656
----
Breaks EXPENSIVE_CHECKS builds.
These intrinsics expand to a variable number of instructions so just like in
ISelLowering.cpp we use custom code to deal with them.
Committing Tim's original patch.
Differential Revision: https://reviews.llvm.org/D65656
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
The current implementation assumes there is an instruction associated
with the transform, but this is not the case for
timm/TargetConstant/immarg values. These transforms should directly
operate on a specific MachineOperand in the source
instruction. TableGen would assert if you attempted to define an
equivalent GISDNodeXFormEquiv using timm when it failed to find the
instruction matcher.
Specially recognize SDNodeXForms on timm, and pass the operand index
to the render function.
Ideally this would be a separate render function type that looks like
void renderFoo(MachineInstrBuilder, const MachineOperand&), but this
proved to be somewhat mechanically painful. Add an optional operand
index which will only be passed if the transform should only look at
the one source operand.
Theoretically it would also be possible to only ever pass the
MachineOperand, and the existing renderers would check the parent. I
think that would be somewhat ugly for the standard usage which may
want to inspect other operands, and I also think MachineOperand should
eventually not carry a pointer to the parent instruction.
Use it in one sample pattern. This isn't a great example, since the
transform exists to satisfy DAG type constraints. This could also be
avoided by just changing the MachineInstr's arbitrary choice of
operand type from i16 to i32. Other patterns have nontrivial uses, but
this serves as the simplest example.
One flaw this still has is if you try to use an SDNodeXForm defined
for imm, but the source pattern uses timm, you still see the "Failed
to lookup instruction" assert. However, there is now a way to avoid
it.
This adds support for selecting a large chunk of the load/store *roW patterns.
This is pretty much a straight port of AArch64DAGToDAGISel::SelectAddrModeWRO
into GISel. The code is very similar to the XRO code. The main difference is
that in the *roW patterns, we want to try and fold in an extend, and *possibly*
a shift along with it. A good portion of this patch is refactoring the existing
XRO code.
- Add selectAddrModeWRO
- Factor out the code from selectAddrModeShiftedExtendXReg which is used by both
selectAddrModeXRO and selectAddrModeWRO into selectExtendedSHL.
This is similar to the function of the same name in AArch64DAGToDAGISel.
- Add support for extends to the factored out code in selectExtendedSHL.
- Teach getExtendTypeForInst how to handle AND masks that are intended to be
used in loads/stores (necessary for this addressing mode.)
- Make getExtendTypeForInst not static because moving it made an annoying diff
and I wanted to have the WRO/XRO functions close to each other while I was
writing the code.
Differential Revision: https://reviews.llvm.org/D72426
This has two main effects:
- Optimizes debug info size by saving 221.86 MB of obj file size in a
Windows optimized+debug build of 'all'. This is 3.03% of 7,332.7MB of
object file size.
- Incremental step towards decoupling target intrinsics.
The enums are still compact, so adding and removing a single
target-specific intrinsic will trigger a rebuild of all of LLVM.
Assigning distinct target id spaces is potential future work.
Part of PR34259
Reviewers: efriedma, echristo, MaskRay
Reviewed By: echristo, MaskRay
Differential Revision: https://reviews.llvm.org/D71320
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
This teaches GISel to select patterns which fold an extend plus optional shift
into the addressing mode. In particular, adds and subs.
Factor out the arith extended register ComplexPatterns in AArch64InstrFormats.td
and create GISel equivalents.
Add some equivalent functions to the ones in AArch64ISelDAGToDAG:
- `selectArithExtendedRegister`
- `narrowExtendRegIfNeeded`
- `getExtendTypeForInst`
`getExtendTypeForInst` includes the checks for loads and stores. This will be
used for WRO addressing modes in loads + stores.
Teach selectCopy to properly handle subregister copies on the same bank in
order to support `narrowExtendRegIfNeeded`. The extended register must be a
GPR32, so we need to support same-bank subregister copies.
Fix a bug in getSubRegForClass which would cause registers on things like
GPR32common to end up getting ssub. Just change the check to look for FPR32
rather than GPR32.
For tests:
- Add select-arith-extended-reg.mir
- Update addsub_ext.ll to include GlobalISel checks
Differential Revision: https://reviews.llvm.org/D66835
llvm-svn: 370410
AMDGPU uses this for some addressing mode selection patterns. The
analysis run itself doesn't do anything so it seems easier to just
always require this than adding a way to opt in.
llvm-svn: 370388
Remove manual selection code for this intrinsic and use a GISelPredicateCode
instead.
This allows us to fully select this intrinsic without any tricky custom C++
matching.
Differential Revision: https://reviews.llvm.org/D65780
llvm-svn: 370380
Add a GISelPredicateCode to ldaxr_*. This allows us to import the patterns for
@llvm.aarch64.ldaxr.*, and thus select them.
Add `isLoadStoreOfNumBytes` for the GISelPredicateCode, since each of these
intrinsics involves the same check.
Add select-ldaxr-intrin.mir, and update arm64-ldxr-stxr.ll.
Differential Revision: https://reviews.llvm.org/D66897
llvm-svn: 370377
Instead of using custom C++ in `earlySelect` for loads and stores, just import
the patterns.
Remove `earlySelectLoad`, since we can just import the work it's doing.
Some minor changes to how `ComplexRendererFns` are returned for the XRO
addressing modes. If you add immediates in two steps, sometimes they are not
imported properly and you only end up with one immediate. I'm not sure if this
is intentional.
- Update load-addressing-modes.mir to include the instructions we can now
import.
- Add a similar test, store-addressing-modes.mir to show which store opcodes we
currently import, and show that we can pull in shifts etc.
- Update arm64-fastisel-gep-promote-before-add.ll to use FastISel instead of
GISel. This test failed with GISel because GISel folds the gep into the load.
The test checks that FastISel doesn't fold non-pointer-width adds into loads.
GISel on the other hand, produces a G_CONSTANT of -128 for the add, and then
a G_GEP, which must be pointer-width.
Note that we don't get STRBRoX right now. It seems like the importer can't
handle `FPR8Op:{ *:[Untyped] }:$Rt` source operands. So, those are not currently
supported.
Differential Revision: https://reviews.llvm.org/D66679
llvm-svn: 369806
Jessica Paquette