In function handleMFLOSlot, we may get a variable LastInstInFunction
with a value of true from function getNextMachineInstr and IInSlot may
be null which would trigger an assert.
So we need to skip this case.
Fix#118223.
Before this patch, redundant COPY couldn't be removed for the following
case:
```
$R0 = OP ...
... // Read of %R0
$R1 = COPY killed $R0
```
This patch adds support for tracking the users of the source register
during backward propagation, so that we can remove the redundant COPY in
the above case and optimize it to:
```
$R1 = OP ...
... // Replace all uses of %R0 with $R1
```
Fix issue1: In mips1-4, require a minimum of 2 instructions between a
mflo/mfhi and the next mul/dmult/div/ddiv/divu/ddivu instruction.
Fix issue2: In mips1-4, should not put mflo into the delay slot for the
return.
Fix https://github.com/llvm/llvm-project/issues/81291
Minor improvement on cc39c3b17fb2598e20ca0854f9fe6d69169d85c7.
Use an aligned stack slot to store the shifted value.
Use the native register width as shifting unit, so the load of the
shift result is aligned.
If the shift amount is a multiple of the native register width, there is
no need to do a follow-up shift after the load. I added new tests for
these cases.
Co-authored-by: Gergely Futo <gergely.futo@hightec-rt.com>
1. Add MipsPat to optimize (andi (srl (truncate i64 $1), x), y) to (andi
(truncate (dsrl i64 $1, x)), y).
2. Add MipsPat to optimize (ext (truncate i64 $1), x, y) to (truncate
(dext i64 $1, x, y)).
The assembly result is the same as gcc.
Fixes https://github.com/llvm/llvm-project/issues/42826
…n MIPS
Modify:
Add a global variable 'CurForbiddenSlotAttr' to save current
instruction's forbidden slot and whether set reorder. This is the
judgment condition for whether to add nop. We would add a couple of
'.set noreorder' and '.set reorder' to wrap the current instruction and
the next instruction.
Then we can get previous instruction`s forbidden slot attribute and
whether set reorder by 'CurForbiddenSlotAttr'.
If previous instruction has forbidden slot and .set reorder is active
and current instruction is CTI. Then emit a NOP after it.
Fix https://github.com/llvm/llvm-project/issues/61045.
Because https://reviews.llvm.org/D158589 was 'Needs Review' state, not
ending, so we commit pull request again.
Do optimization to turn x >> (shift & 31/63) into a single srlv instead
of andi + srlv, since the mips variable shift instruction already
implicitly masks the shift, like x86, wasm and AMDGPU. Copy the
X86DAGToDAGISel::isUnneededShiftMask() function to MIPS for checking
whether need combine two instructions to one.
If we start with an i128 shift, the initial shift amount would usually
have zeros in bit 8 and above. xoring the shift amount with -1 will set
those upper bits to 1. If DAGCombiner is able to prove those bits are
now 1, then the shift that uses the xor will be replaced with undef.
Which we don't want.
Reduce the xor constant to VT.bits-1 where VT is half the size of the
larger shift type. This avoids toggling the upper bits. The hardware
shift instruction only uses the lower bits of the shift amount. I assume
the code used NOT because the hardware doesn't use the upper bits, but
that isn't compatible with the LLVM poison semantics.
Fixes#71142.
PR #66334 tried to renumber slot indexes before register allocation, but
the numbering was still affected by list entries for instructions which
had been erased. Fix this to make the register allocator's live range
length heuristics even less dependent on the history of how instructions
have been added to and removed from SlotIndexes's maps.
https://reviews.llvm.org/D140493 is going to teach SROA how to promote allocas
that have variably-indexed loads. That does bring up questions of cost model,
since that requires creating wide shifts.
Indeed, our legalization for them is not optimal.
We either split it into parts, or lower it into a libcall.
But if the shift amount is by a multiple of CHAR_BIT,
we can also legalize it throught stack.
The basic idea is very simple:
1. Get a stack slot 2x the width of the shift type
2. store the value we are shifting into one half of the slot
3. pad the other half of the slot. for logical shifts, with zero, for arithmetic shift with signbit
4. index into the slot (starting from the base half into which we spilled, either upwards or downwards)
5. load
6. split loaded integer
This works for both little-endian and big-endian machines:
https://alive2.llvm.org/ce/z/YNVwd5
And better yet, if the original shift amount was not a multiple of CHAR_BIT,
we can just shift by that remainder afterwards: https://alive2.llvm.org/ce/z/pz5G-K
I think, if we are going perform shift->shift-by-parts expansion more than once,
we should instead go through stack, which is what this patch does.
Reviewed By: craig.topper
Differential Revision: https://reviews.llvm.org/D140638
This reverts commit 122efef8ee9be57055d204d52c38700fe933c033.
- Patch fixed to not reuse definitions from predecessors in EH landing pads.
- Late review suggestions (by MaskRay) have been addressed.
- M68k/pipeline.ll test updated.
- Init captures added in processBlock() to avoid capturing structured bindings.
- RISCV has this disabled for now.
Original commit message:
A new pass MachineLateInstrsCleanup is added to be run after PEI.
This is a simple pass that removes redundant and identical instructions
whenever found by scanning the MF once while keeping track of register
definitions in a map. These instructions are typically immediate loads
resulting from rematerialization, and address loads emitted by target in
eliminateFrameInde().
This is enabled by default, but a target could easily disable it by means of
'disablePass(&MachineLateInstrsCleanupID);'.
This late cleanup is naturally not "optimal" in removing instructions as it
is done by looking at phys-regs, but still quite effective. It would be
desirable to improve other parts of CodeGen and avoid these redundant
instructions in the first place, but there are no ideas for this yet.
Differential Revision: https://reviews.llvm.org/D123394
Reviewed By: RKSimon, foad, craig.topper, arsenm, asb
Init captures added in processBlock() to avoid capturing structured bindings,
which caused the build problems (with clang).
RISCV has this disabled for now until problems relating to post RA pseudo
expansions are resolved.
A new pass MachineLateInstrsCleanup is added to be run after PEI.
This is a simple pass that removes redundant and identical instructions
whenever found by scanning the MF once while keeping track of register
definitions in a map. These instructions are typically immediate loads
resulting from rematerialization, and address loads emitted by target in
eliminateFrameInde().
This is enabled by default, but a target could easily disable it by means of
'disablePass(&MachineLateInstrsCleanupID);'.
This late cleanup is naturally not "optimal" in removing instructions as it
is done by looking at phys-regs, but still quite effective. It would be
desirable to improve other parts of CodeGen and avoid these redundant
instructions in the first place, but there are no ideas for this yet.
Differential Revision: https://reviews.llvm.org/D123394
Reviewed By: RKSimon, foad, craig.topper, arsenm, asb
Add the instructions and patterns for loads and stores in microMIPSr3
when a 64 bit FPU is present. Previously, this would lead to an
instruction selection failure.
This resolves PR/49200.
Thanks to jdeguire for reporting the issue!
Differential Revision: https://reviews.llvm.org/D124723
Previously, the choice between the instruction selection of ISD::FABS was
decided at the point of setting the MIPS target lowering operation choice
either `Custom` lowering or `Legal`. This lead to instruction selection
failures as functions could be marked as having no NaNs.
Changing the lowering to always be `Custom` and directly handling the
the cases where MIPS selects the instructions for ISD::FABS resolves
this crash.
Thanks to kray for reporting the issue and to Simon Atanasyan for producing
the reduced test case.
This resolves PR/53722.
Differential Revision: https://reviews.llvm.org/D124651
This reverts commit 83a798d4b0e17ac41d5430f1290d3661343eee1e.
As discussed in D120714 with @thakis, the patch added unneeded complexity
without noticeable benefits.
Place PersistentId declaration under #if LLVM_ENABLE_ABI_BREAKING_CHECKS to
reduce memory usage when it is not needed.
Differential Revision: https://reviews.llvm.org/D120714
MIPS I, II, and III have delay slots for floating point
comparisons and floating point register transfers (mtc1, mfc1).
Currently, these are not taken into account and thus broken code
may be generated on these targets. This patch inserts nops
as necessary, while attempting to leave the current instruction
if it is safe to stay.
The tests in this patch were updated by @sajattack
Patch by @overdrivenpotato (Marko Mijalkovic <marko.mijalkovic97@gmail.com>)
Differential Revision: https://reviews.llvm.org/D115127
Similar to D108842 and D108844.
__has_builtin(builtin_mul_overflow) returns true for 32b MIPS targets,
but Clang is deferring to compiler RT when encountering long long types.
This breaks MIPS malta_defconfig builds of the Linux kernel that are
using __builtin_mul_overflow with these types for these targets.
If the semantics of __has_builtin mean "the compiler resolves these,
always" then we shouldn't conditionally emit a libcall.
This will still need to be worked around in the Linux kernel in order to
continue to support malta_defconfig builds of the Linux kernel for this
target with older releases of clang.
Link: https://bugs.llvm.org/show_bug.cgi?id=28629
Link: https://github.com/ClangBuiltLinux/linux/issues/1438
Reviewed By: rengolin
Differential Revision: https://reviews.llvm.org/D108926
Currently isReallyTriviallyReMaterializableGeneric() implementation
prevents rematerialization on any virtual register use on the grounds
that is not a trivial rematerialization and that we do not want to
extend liveranges.
It appears that LRE logic does not attempt to extend a liverange of
a source register for rematerialization so that is not an issue.
That is checked in the LiveRangeEdit::allUsesAvailableAt().
The only non-trivial aspect of it is accounting for tied-defs which
normally represent a read-modify-write operation and not rematerializable.
The test for a tied-def situation already exists in the
/CodeGen/AMDGPU/remat-vop.mir,
test_no_remat_v_cvt_f32_i32_sdwa_dst_unused_preserve.
The change has affected ARM/Thumb, Mips, RISCV, and x86. For the targets
where I more or less understand the asm it seems to reduce spilling
(as expected) or be neutral. However, it needs a review by all targets'
specialists.
Differential Revision: https://reviews.llvm.org/D106408
Currently isReallyTriviallyReMaterializableGeneric() implementation
prevents rematerialization on any virtual register use on the grounds
that is not a trivial rematerialization and that we do not want to
extend liveranges.
It appears that LRE logic does not attempt to extend a liverange of
a source register for rematerialization so that is not an issue.
That is checked in the LiveRangeEdit::allUsesAvailableAt().
The only non-trivial aspect of it is accounting for tied-defs which
normally represent a read-modify-write operation and not rematerializable.
The test for a tied-def situation already exists in the
/CodeGen/AMDGPU/remat-vop.mir,
test_no_remat_v_cvt_f32_i32_sdwa_dst_unused_preserve.
The change has affected ARM/Thumb, Mips, RISCV, and x86. For the targets
where I more or less understand the asm it seems to reduce spilling
(as expected) or be neutral. However, it needs a review by all targets'
specialists.
Differential Revision: https://reviews.llvm.org/D106408
This adds custom lowering for truncating stores when operating on
fixed length vectors in SVE. It also includes a DAG combine to
fold extends followed by truncating stores into non-truncating
stores in order to prevent this pattern appearing once truncating
stores are supported.
Currently truncating stores are not used in certain cases where
the size of the vector is larger than the target vector width.
Differential Revision: https://reviews.llvm.org/D104471
This adds custom lowering for truncating stores when operating on
fixed length vectors in SVE. It also includes a DAG combine to
fold extends followed by truncating stores into non-truncating
stores in order to prevent this pattern appearing once truncating
stores are supported.
Currently truncating stores are not used in certain cases where
the size of the vector is larger than the target vector width.
Differential Revision: https://reviews.llvm.org/D104471
This also removes a pattern from RISCV that is no longer needed
since the sexti32 on the LHS of the srem in the pattern implies
the result is sign extended so the sign_extend_inreg should be
removed in DAG combine now.
Reviewed By: luismarques, RKSimon
Differential Revision: https://reviews.llvm.org/D97133
As detailed in https://blog.regehr.org/archives/1709 we don't make use of the known leading/trailing zeros for shifted values in cases where we don't know the shift amount value.
This patch adds support to SelectionDAG::ComputeKnownBits to use KnownBits::countMinTrailingZeros and countMinLeadingZeros to set the minimum guaranteed leading/trailing known zero bits.
Differential Revision: https://reviews.llvm.org/D72573
There is not match for the `MipsJmpLink texternalsym` and `MipsJmpLink
tglobaladdr` patterns for microMIPS R6. As a result LLVM incorrectly
selects the `JALRC16` compact 2-byte instruction which takes a target
instruction address from a register only and assign `R_MIPS_32` relocation
for this instruction. This relocation completely overwrites `JALRC16`
and nearby instructions.
This patch adds missed matching patterns, selects `BALC` instruction and
assign a correct `R_MICROMIPS_PC26_S1` relocation.
Differential Revision: https://reviews.llvm.org/D64552
llvm-svn: 365870
On Mips32r2 bitcast can be expanded to two sw instructions and an ldc1
when using bitcast i64 to double or an sdc1 and two lw instructions when
using bitcast double to i64. By introducing custom lowering that uses
mtc1/mthc1 we can avoid excessive instructions.
Patch by Mirko Brkusanin.
Differential Revision: https://reviews.llvm.org/D61069
llvm-svn: 359171
Before this change LLVM emits non-microMIPS variant of the `mov.d`
command for microMIPS code.
Differential Revision: http://reviews.llvm.org/D59045
llvm-svn: 356052
A pattern needed to match TruncIntFP was missing. This was causing multiple
tests from llvm test suite to fail during compilation for micromips.
Patch by Mirko Brkusanin.
Differential Revision: https://reviews.llvm.org/D58722
llvm-svn: 355825
Instruction abs.[ds] is not generating correct result when working
with NaNs for revisions prior mips32r6 and mips64r6.
To generate a sequence which always produce a correct result, but also
to allow user more control on how his code is compiled, attribute
+abs2008 is added, so user can choose legacy or 2008.
By default legacy mode is used on revisions prior R6. Mips32r6 and
mips64r6 use abs2008 mode by default.
Differential Revision: https://reviews.llvm.org/D35983
llvm-svn: 352370
The callee address is added as an optional operand (MCSymbol) in
AdjustInstrPostInstrSelection() and then used by asm printer to insert:
'.reloc tmplabel, R_MIPS_JALR, symbol
tmplabel:'.
Controlled with '-mips-jalr-reloc', default is true.
Differential revision: https://reviews.llvm.org/D56694
llvm-svn: 351485
With this patch, shifts are lowered to optimal number of instructions
necessary to shift types larger than the general purpose register size.
This resolves PR/32293.
Thanks to Kyle Butt for reporting the issue!
Differential Revision: https://reviews.llvm.org/D56320
llvm-svn: 351059
