69 Commits

Author SHA1 Message Date
Evgenii Kudriashov
d365a45cb3
[GlobalISel] Introduce G_TRAP, G_DEBUGTRAP, G_UBSANTRAP (#84941)
Here we introduce three new GMIR instructions to cover a set of trap
intrinsics. The idea behind it is that generic intrinsics shouldn't be
used with G_INTRINSIC opcode.

These new instructions can match perfectly with existing trap ISD nodes.
It allows X86, AArch64, RISCV and Mips to reuse SelectionDAG patterns for
selection and avoid manual selection. However AMDGPU is an exception. It
selects traps during legalization regardless SelectionDAG or GlobalISel.

Since there are not many places where traps are used, this change
attempts to clean up all the usages of G_INTRINSIC with trap intrinsics. So,
there is no stage when both G_TRAP and
G_INTRINSIC_W_SIDE_EFFECTS(@llvm.trap) are allowed.
2024-03-23 13:12:44 +01:00
darkbuck
d0f4663f48
[GlobalISel][Mips] Global ISel for brcond
- Enable equivalent between `brcond` and `G_BRCOND`.
- Remove the manual selection of `G_BRCOND` in Mips. Revise test cases.

Reviewers: petar-avramovic, bcardosolopes, arsenm

Reviewed By: arsenm

Pull Request: https://github.com/llvm/llvm-project/pull/81306
2024-02-10 21:44:05 -05:00
Nikita Popov
ff9af4c43a [CodeGen] Convert tests to opaque pointers (NFC) 2024-02-05 14:07:09 +01:00
Quentin Dian
112fba974c
[MIRPrinter] Don't print line break when there is no instructions (NFC) (#80147)
Per #80143, we can remove the extra line break when there is no
instruction.
2024-02-01 22:10:52 +08:00
pvanhout
c3cfbbc416 [GlobalISel] Add dead flags to implicit defs in ISel
Checks for implicit defs that are unused within a pattern and mark them as dead.

This is done directly at the TableGen level forr efficiency.
The instructions are directly created with the "dead" operand and no further analysis is needed later.

Reviewed By: arsenm

Differential Revision: https://reviews.llvm.org/D157273
2023-08-09 14:20:51 +02:00
Nikita Popov
60442f0d44 [CodeGen] Convert some tests to opaque pointers (NFC)
These are mostly MIR tests, which I did not handle during previous
conversions.
2023-01-05 13:21:20 +01:00
Matt Arsenault
fae05692a3 CodeGen: Print/parse LLTs in MachineMemOperands
This will currently accept the old number of bytes syntax, and convert
it to a scalar. This should be removed in the near future (I think I
converted all of the tests already, but likely missed a few).

Not sure what the exact syntax and policy should be. We can continue
printing the number of bytes for non-generic instructions to avoid
test churn and only allow non-scalar types for generic instructions.

This will currently print the LLT in parentheses, but accept parsing
the existing integers and implicitly converting to scalar. The
parentheses are a bit ugly, but the parser logic seems unable to deal
without either parentheses or some keyword to indicate the start of a
type.
2021-06-30 16:54:13 -04:00
Petar Avramovic
5171d1523d [MIPS GlobalISel] Select 4 byte unaligned load and store
Improve legality checks for load and store, 4 byte scalar
load and store are now legal for all subtargets.
During regbank selection 4 byte unaligned loads and stores
for MIPS32r5 and older get mapped to gprb.
Select 4 byte unaligned loads and stores for MIPS32r5.
Fix tests that unintentionally had unaligned load or store.

Differential Revision: https://reviews.llvm.org/D74624
2020-02-19 11:57:06 +01:00
Petar Avramovic
92c80529dd [MIPS GlobalISel] RegBankSelect G_MERGE_VALUES and G_UNMERGE_VALUES
Consider large operands in G_MERGE_VALUES and G_UNMERGE_VALUES as
Ambiguous during regbank selection.
Introducing new InstType AmbiguousWithMergeOrUnmerge which will
allow us to recognize whether to narrow scalar or use s64:fprb.

This change exposed a bug when reusing data from TypeInfoForMF.
Thus when Instr is about to get destroyed (using narrow scalar)
clear its data in TypeInfoForMF. Internal data is saved based on
Instr's address, and it will no longer be valid.
Add detailed asserts for InstType and operand size.

Generate generic instructions instead of MIPS target instructions
during argument lowering and custom legalizer.
Select G_UNMERGE_VALUES and G_MERGE_VALUES when proper banks are
selected: {s32:gprb, s32:gprb, s64:fprb} for G_UNMERGE_VALUES and
{s64:fprb, s32:gprb, s32:gprb} for G_MERGE_VALUES.
Update tests. One improvement is when floating point argument in
gpr(or two gprs) gets passed to another function through gpr
unnecessary fpr-to-gpr moves are no longer generated.

Differential Revision: https://reviews.llvm.org/D74623
2020-02-19 10:09:52 +01:00
Petar Avramovic
2b66d32f3f [MIPS GlobalISel] Select count leading zeros
llvm.ctlz.<type> intrinsic has additional i1 argument is_zero_undef,
it tells whether zero as the first argument produces a defined result.
MIPS clz instruction returns 32 for zero input.
G_CTLZ is generated from llvm.ctlz.<type> (<type> <src>, i1 false)
intrinsics, clang generates these intrinsics from __builtin_clz and
__builtin_clzll.
G_CTLZ_ZERO_UNDEF can also be generated from llvm.ctlz with true as
second argument. It is also traditionally part of and many algorithms
that are now predicated on avoiding zero-value inputs.

Add narrow scalar for G_CTLZ (algorithm uses G_CTLZ_ZERO_UNDEF).
Lower G_CTLZ_ZERO_UNDEF and select G_CTLZ for MIPS32.

Differential Revision: https://reviews.llvm.org/D73214
2020-01-27 09:43:38 +01:00
Petar Avramovic
94a24e7a40 [MIPS GlobalISel] Select bswap
G_BSWAP is generated from llvm.bswap.<type> intrinsics, clang genrates
these intrinsics from __builtin_bswap32 and __builtin_bswap64.
Add lower and narrowscalar for G_BSWAP.
Lower G_BSWAP on MIPS32, select G_BSWAP on MIPS32 revision 2 and later.

Differential Revision: https://reviews.llvm.org/D71362
2019-12-30 11:13:22 +01:00
Petar Avramovic
1f559353a7 [MIPS GlobalISel] Select andi, ori and xori
Introduce IntImmLeaf version of PatLeaf immZExt16 for 32-bit immediates.
Change immZExt16 with imm32ZExt16 for andi, ori and xori.
This keeps same behavior for SDAG and allows for GlobalISel selectImpl
to select 'G_CONSTANT imm' + G_AND, G_OR, G_XOR into ANDi, ORi, XORi,
respectively, when 32-bit imm satisfies imm32ZExt16 predicate: zero
extending 16 low bits of imm is equal to imm.
Large number of test changes comes from zero extending of small types
which is transformed into 'and' with bitmask in legalizer.

Differential Revision:https://reviews.llvm.org/D70185
2019-11-15 11:41:25 +01:00
Petar Avramovic
dda8e95540 [MIPS GlobalISel] Select addiu
Introduce IntImmLeaf version of PatLeaf immSExt16 for 32-bit immediates.
Change immSExt16 with imm32SExt16 for addiu.
This keeps same behavior for SDAG and allows for GlobalISel selectImpl
to select 'G_CONSTANT imm' + G_ADD into ADDIu when 32-bit imm satisfies
imm32SExt16 predicate: sign extending 16 low bits of imm is equal to imm.

Differential Revision: https://reviews.llvm.org/D70184
2019-11-15 11:36:13 +01:00
Daniel Sanders
e74c5b9661 [globalisel] Rename G_GEP to G_PTR_ADD
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
2019-11-05 10:31:17 -08:00
Petar Avramovic
417dd67825 [MIPS GlobalISel] Select MSA vector generic and builtin fsqrt
selectImpl is able to select G_FSQRT when we set bank for vector
operands to fprb. Add detailed tests.
Note: G_FSQRT is generated from llvm-ir intrinsics llvm.sqrt.*,
and at the moment MIPS is not able to generate this intrinsic for
vector type (some targets generate vector llvm.sqrt.* from calls
to a builtin function).
__builtin_msa_fsqrt_<format> will be transformed into G_FSQRT
in legalizeIntrinsic and selected in the same way.

Differential Revision: https://reviews.llvm.org/D69376
2019-10-25 14:45:14 +02:00
Petar Avramovic
e3b49df50e [MIPS GlobalISel] Select MSA vector generic and builtin fabs
selectImpl is able to select G_FABS when we set bank for vector
operands to fprb. Add detailed tests.
Note: G_FABS is generated from llvm-ir intrinsics llvm.fabs.*,
and at the moment MIPS is not able to generate this intrinsic for
vector type (some targets generate vector llvm.fabs.* from calls
to a builtin function).
We can handle fabs using __builtin_msa_fmax_a_<format> and passing
same vector as both arguments. __builtin_msa_fmax_a_<format> will
be directly selected into FMAX_A_<format> in legalizeIntrinsic.

Differential Revision: https://reviews.llvm.org/D69346
2019-10-24 13:45:26 +02:00
Petar Avramovic
914ce66413 [MIPS GlobalISel] MSA vector generic and builtin fadd, fsub, fmul, fdiv
Select vector G_FADD, G_FSUB, G_FMUL and G_FDIV for MIPS32 with MSA. We
have to set bank for vector operands to fprb and selectImpl will do the
rest. __builtin_msa_fadd_<format>, __builtin_msa_fsub_<format>,
__builtin_msa_fmul_<format> and __builtin_msa_fdiv_<format> will be
transformed into G_FADD, G_FSUB, G_FMUL and G_FDIV in legalizeIntrinsic
respectively and selected in the same way.

Differential Revision: https://reviews.llvm.org/D69340
2019-10-24 10:15:07 +02:00
Petar Avramovic
1d7f79c017 [MIPS GlobalISel] MSA vector generic and builtin sdiv, srem, udiv, urem
Select vector G_SDIV, G_SREM, G_UDIV and G_UREM for MIPS32 with MSA. We
have to set bank for vector operands to fprb and selectImpl will do the
rest. __builtin_msa_div_s_<format>, __builtin_msa_mod_s_<format>,
__builtin_msa_div_u_<format> and __builtin_msa_mod_u_<format> will be
transformed into G_SDIV, G_SREM, G_UDIV and G_UREM in legalizeIntrinsic
respectively and selected in the same way.

Differential Revision: https://reviews.llvm.org/D69333
2019-10-24 10:03:36 +02:00
Petar Avramovic
d1815dacb0 [MIPS GlobalISel] Select MSA vector generic and builtin mul
Select vector G_MUL for MIPS32 with MSA. We have to set bank
for vector operands to fprb and selectImpl will do the rest.
Manual selection of G_MUL is now done for gprb only.
__builtin_msa_mulv_<format> will be transformed into G_MUL
in legalizeIntrinsic and selected in the same way.

Differential Revision: https://reviews.llvm.org/D69310
2019-10-23 11:22:07 +02:00
Petar Avramovic
c46d24f5c3 [MIPS GlobalISel] Select MSA vector generic and builtin sub
Select vector G_SUB for MIPS32 with MSA. We have to set bank
for vector operands to fprb and selectImpl will do the rest.
__builtin_msa_subv_<format> will be transformed into G_SUB
in legalizeIntrinsic and selected in the same way.
__builtin_msa_subvi_<format> will be directly selected into
SUBVI_<format> in legalizeIntrinsic.

Differential Revision: https://reviews.llvm.org/D69306
2019-10-23 11:15:25 +02:00
Petar Avramovic
e4af9de36c [MIPS GlobalISel] Select MSA vector generic and builtin add
Select vector G_ADD for MIPS32 with MSA. We have to set bank
for vector operands to fprb and selectImpl will do the rest.
__builtin_msa_addv_<format> will be transformed into G_ADD
in legalizeIntrinsic and selected in the same way.
__builtin_msa_addvi_<format> will be directly selected into
ADDVI_<format> in legalizeIntrinsic. MIR tests for it have
unnecessary additional copies. Capture current state of tests
with run-pass=legalizer with a test in test/CodeGen/MIR/Mips.

Differential Revision: https://reviews.llvm.org/D68984

llvm-svn: 375501
2019-10-22 13:51:57 +00:00
Petar Avramovic
599591f3d4 [MIPS GlobalISel] Add MSA registers to fprb. Select vector load, store
Add vector MSA register classes to fprb, they are 128 bit wide.
MSA instructions use the same registers for both integer and floating
point operations. Therefore we only need to check for vector element
size during legalization or instruction selection.

Add helper function in MipsLegalizerInfo and switch to legalIf
LegalizeRuleSet to keep legalization rules compact since they depend
on MipsSubtarget and presence of MSA.
fprb is assigned to all vector operands.
Move selectLoadStoreOpCode to MipsInstructionSelector in order to
reduce number of arguments.

Differential Revision: https://reviews.llvm.org/D68867

llvm-svn: 374872
2019-10-15 09:30:08 +00:00
Petar Avramovic
c063b0b0d3 [MIPS GlobalISel] VarArg argument lowering, select G_VASTART and vacopy
CC_Mips doesn't accept vararg functions for O32, so we have to explicitly
use CC_Mips_FixedArg.
For lowerCall we now properly figure out whether callee function is vararg
or not, this has no effect for O32 since we always use CC_Mips_FixedArg.
For lower formal arguments we need to copy arguments in register to stack
and save pointer to start for argument list into MipsMachineFunction
object so that G_VASTART could use it during instruction select.
For vacopy we need to copy content from one vreg to another,
load and store are used for that purpose.

Differential Revision: https://reviews.llvm.org/D67756

llvm-svn: 372555
2019-09-23 08:11:41 +00:00
Petar Avramovic
ff6ac1eb5f [MIPS GlobalISel] Select indirect branch
Select G_BRINDIRECT for MIPS32.

Differential Revision: https://reviews.llvm.org/D67441

llvm-svn: 371730
2019-09-12 11:44:36 +00:00
Petar Avramovic
75e43a607c [MIPS GlobalISel] Select G_IMPLICIT_DEF
G_IMPLICIT_DEF is used for both integer and floating point implicit-def.
Handle G_IMPLICIT_DEF as ambiguous opcode in MipsRegisterBankInfo.
Select G_IMPLICIT_DEF for MIPS32.

Differential Revision: https://reviews.llvm.org/D67439

llvm-svn: 371727
2019-09-12 11:32:38 +00:00
Guillaume Chatelet
48904e9452 [Alignment] Use llvm::Align in MachineFunction and TargetLowering - fixes mir parsing
Summary:
This catches malformed mir files which specify alignment as log2 instead of pow2.
See https://reviews.llvm.org/D65945 for reference,

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: MatzeB, qcolombet, dschuff, arsenm, sdardis, nemanjai, jvesely, nhaehnle, hiraditya, kbarton, asb, rbar, johnrusso, simoncook, apazos, sabuasal, niosHD, jrtc27, MaskRay, zzheng, edward-jones, atanasyan, rogfer01, MartinMosbeck, brucehoult, the_o, PkmX, jocewei, jsji, Petar.Avramovic, asbirlea, s.egerton, pzheng, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D67433

llvm-svn: 371608
2019-09-11 11:16:48 +00:00
Petar Avramovic
a4bfc8dfda [MIPS GlobalISel] Select G_FENCE
G_FENCE comes form fence instruction. For MIPS fence is generated in
AtomicExpandPass when atomic instruction gets surrounded with fence
instruction when needed.
G_FENCE arguments don't have LLT, because of that there is no job for
legalizer and regbankselect. Instruction select G_FENCE for MIPS32.

Differential Revision: https://reviews.llvm.org/D67181

llvm-svn: 371056
2019-09-05 11:20:32 +00:00
Matt Arsenault
8ec5c10042 GlobalISel/TableGen: Handle setcc patterns
This is a special case because one node maps to two different G_
instructions, and the operand order is changed.

This mostly enables G_FCMP for AMDPGPU. G_ICMP is still manually
selected for now since it has the SALU and VALU complication to deal
with.

llvm-svn: 370280
2019-08-29 01:13:41 +00:00
Petar Avramovic
caef930699 [MIPS GlobalISel] Select jump_table and brjt
G_JUMP_TABLE and G_BRJT appear from translation of switch statement.
Select these two instructions for MIPS32, both pic and non-pic.

Differential Revision: https://reviews.llvm.org/D65861

llvm-svn: 368274
2019-08-08 10:21:12 +00:00
Petar Avramovic
8a40cedfe6 [MIPS GlobalISel] Fold load/store + G_GEP + G_CONSTANT
Fold load/store + G_GEP + G_CONSTANT when
immediate in G_CONSTANT fits into 16 bit signed integer.

Differential Revision: https://reviews.llvm.org/D65507

llvm-svn: 367535
2019-08-01 09:40:13 +00:00
Petar Avramovic
b1fc6f6130 [MIPS GlobalISel] Select inttoptr and ptrtoint
Select G_INTTOPTR and G_PTRTOINT for MIPS32.

Differential Revision: https://reviews.llvm.org/D65217

llvm-svn: 367104
2019-07-26 13:08:06 +00:00
Petar Avramovic
1e62635d05 [MIPS GlobalISel] ClampScalar and select pointer G_ICMP
Add narrowScalar to half of original size for G_ICMP.
ClampScalar G_ICMP's operands 2 and 3 to to s32.
Select G_ICMP for pointers for MIPS32. Pointer compare is same
as for integers, it is enough to declare them as legal type.

Differential Revision: https://reviews.llvm.org/D64856

llvm-svn: 366317
2019-07-17 12:08:01 +00:00
Petar Avramovic
7d0778ea6b [MIPS GlobalISel] Select float and double phi
Select float and double phi for MIPS32.

Differential Revision: https://reviews.llvm.org/D64420

llvm-svn: 365627
2019-07-10 13:18:13 +00:00
Petar Avramovic
7b31491ae2 [MIPS GlobalISel] Select float and double load and store
Select float and double load and store for MIPS32.

Differential Revision: https://reviews.llvm.org/D64419

llvm-svn: 365626
2019-07-10 12:55:21 +00:00
Petar Avramovic
dbb6d01d34 [MIPS GlobalISel] Regbanks for G_SELECT. Select i64, f32 and f64 select
Select gprb or fprb when def/use register operand of G_SELECT is
used/defined by either:
 copy to/from physical register or
 instruction with only one mapping available for that use/def operand.

Integer s64 select is handled with narrowScalar when mapping is applied,
produced artifacts are combined away. Manually set gprb to all register
operands of instructions created during narrowScalar.

For selection of floating point s32 or s64 select it is enough to set
fprb of appropriate size and selectImpl will do the rest.

Differential Revision: https://reviews.llvm.org/D64350

llvm-svn: 365492
2019-07-09 14:30:29 +00:00
Petar Avramovic
153bd24eda [MIPS GlobalISel] Select integer to floating point conversions
Select G_SITOFP and G_UITOFP for MIPS32.

Differential Revision: https://reviews.llvm.org/D63542

llvm-svn: 363912
2019-06-20 09:05:02 +00:00
Petar Avramovic
4b4dae1c76 [MIPS GlobalISel] Select floating point to integer conversions
Select G_FPTOSI and G_FPTOUI for MIPS32.

Differential Revision: https://reviews.llvm.org/D63541

llvm-svn: 363911
2019-06-20 08:52:53 +00:00
Sander de Smalen
5d6ee76c16 Describe stack-id as an enum
This patch changes MIR stack-id from an integer to an enum,
and adds printing/parsing support for this in MIR files. The default
stack-id '0' is now renamed to 'default'.

This should make MIR tests that have stack objects with different stack-ids
more descriptive. It also clarifies code operating on StackID.

Reviewers: arsenm, thegameg, qcolombet

Reviewed By: arsenm

Differential Revision: https://reviews.llvm.org/D60137

llvm-svn: 363533
2019-06-17 09:13:29 +00:00
Petar Avramovic
81132ce0e9 [MIPS GlobalISel] Select sqrt
Select G_FSQRT for MIPS32.

Differential Revision: https://reviews.llvm.org/D62905

llvm-svn: 362692
2019-06-06 10:00:41 +00:00
Petar Avramovic
0a1fd355b2 [MIPS GlobalISel] Select fabs
Select G_FABS for MIPS32.

Differential Revision: https://reviews.llvm.org/D62903

llvm-svn: 362690
2019-06-06 09:22:37 +00:00
Petar Avramovic
a7d0006447 [MIPS GlobalISel] Select fpext and fptrunc
Select G_FPEXT and G_FPTRUNC for MIPS32.

Differential Revision: https://reviews.llvm.org/D62902

llvm-svn: 362689
2019-06-06 09:16:58 +00:00
Petar Avramovic
22e99c434f [MIPS GlobalISel] Select fcmp
Select floating point compare for MIPS32.

Differential Revision: https://reviews.llvm.org/D62721

llvm-svn: 362603
2019-06-05 14:03:13 +00:00
Petar Avramovic
efcd3c0009 [MIPS GlobalISel] Handle position independent code
Handle position independent code for MIPS32.
When callee is global address, lower call will emit callee
as G_GLOBAL_VALUE and add target flag if needed.
Support $gp in getRegBankFromRegClass().
Select G_GLOBAL_VALUE, specially handle case when
there are target flags attached by lowerCall.

Differential Revision: https://reviews.llvm.org/D62589

llvm-svn: 362210
2019-05-31 08:27:06 +00:00
Petar Avramovic
afa3afa384 [MIPS GlobalISel] Select floating point arithmetic operations
Select 32 and 64 bit floating point add, sub, mul and div for MIPS32.

Differential Revision: https://reviews.llvm.org/D60191

llvm-svn: 357584
2019-04-03 14:12:59 +00:00
Petar Avramovic
1af05df3de [MIPS GlobalISel] Select float constants
Select 32 and 64 bit float constants for MIPS32.

Differential Revision: https://reviews.llvm.org/D59933

llvm-svn: 357183
2019-03-28 16:58:12 +00:00
Petar Avramovic
a034a64f84 [MIPS GlobalISel] Select copy for arguments from FPRBRegBank
Move selectCopy into MipsInstructionSelector class.
Select copy for arguments from FPRBRegBank for MIPS32.

Differential Revision: https://reviews.llvm.org/D59644

llvm-svn: 356886
2019-03-25 11:38:06 +00:00
Petar Avramovic
3e0da146ac [MIPS GlobalISel] Improve selection of constants
Certain 32 bit constants can be generated with a single instruction
instead of two. Implement materialize32BitImm function for MIPS32.

Differential Revision: https://reviews.llvm.org/D59369

llvm-svn: 356238
2019-03-15 07:07:50 +00:00
Petar Avramovic
3d3120dc9a [MIPS GlobalISel] Fix mul operands
Unsigned mul high for MIPS32 is selected into two PseudoInstructions:
PseudoMULTu and PseudoMFHI that use accumulator register class ACC64 for
some of its operands. Registers in this class have appropriate hi and lo
register as subregisters: $lo0 and $hi0 are subregisters of $ac0 etc.
mul instruction implicit-defs $lo0 and $hi0 according to MipsInstrInfo.td.
In functions where mul and PseudoMULTu are present fastRegisterAllocator
will "run out of registers during register allocation" because
'calcSpillCost' for $ac0 will return spillImpossible because subregisters
$lo0 and $hi0 of $ac0 are reserved by mul instruction above. A solution is
to mark implicit-defs of $lo0 and $hi0 as dead in mul instruction.

Differential Revision: https://reviews.llvm.org/D58715

llvm-svn: 355594
2019-03-07 13:28:29 +00:00
Vlad Tsyrklevich
8925138007 Revert "[MIPS GlobalISel] Fix mul operands"
This reverts commit r355178, it is causing ASan failures on the
sanitizer bots.

llvm-svn: 355219
2019-03-01 18:58:22 +00:00
Petar Avramovic
9bf43b5c26 [MIPS GlobalISel] Fix mul operands
Unsigned mul high for MIPS32 is selected into two PseudoInstructions:
PseudoMULTu and PseudoMFHI that use accumulator register class ACC64 for
some of its operands. Registers in this class have appropriate hi and lo
register as subregisters: $lo0 and $hi0 are subregisters of $ac0 etc.
mul instruction implicit-defs $lo0 and $hi0 according to MipsInstrInfo.td.
In functions where mul and PseudoMULTu are present fastRegisterAllocator
will "run out of registers during register allocation" because
'calcSpillCost' for $ac0 will return spillImpossible because subregisters
$lo0 and $hi0 of $ac0 are reserved by mul instruction above. A solution is
to mark implicit-defs of $lo0 and $hi0 as dead in mul instruction.

Differential Revision: https://reviews.llvm.org/D58715

llvm-svn: 355178
2019-03-01 07:35:57 +00:00