Commit Graph

5949 Commits

Author SHA1 Message Date
Christopher Tetreault 49fd24fe9e Clean up usages of asserting vector getters in Type
Summary:
Remove usages of asserting vector getters in Type in preparation for the
VectorType refactor. The existence of these functions complicates the
refactor while adding little value.

Reviewers: hfinkel, efriedma, sdesmalen

Reviewed By: efriedma

Subscribers: wuzish, nemanjai, hiraditya, kbarton, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D77266
2020-04-08 16:10:55 -07:00
Sean Fertile d0b57b41f4 [PowerPC][AIX][NFC] Replace deprecated getByValAlign call.
Replace call to deprecated 'getByValAlign()' with
'getNonZeroByValAlign()'.
2020-04-08 13:27:39 -04:00
Matt Arsenault ca0ace7298 CodeGen: Use Register in MachineBasicBlock 2020-04-08 12:10:58 -04:00
Matt Arsenault 84aa58cbe2 CodeGen: Use Register in TargetLowering 2020-04-08 12:10:58 -04:00
Sean Fertile 8abfd2c3bb [PowerPC][AIX] Enable passing byval formal arguments in multiple registers.
Any or all the argument registers can be used to pass a byval formal
argument, with the limitation that the argument must fit in the
available registers (ie: is not split between registers and stack).

Differential Revision: https://reviews.llvm.org/D76902
2020-04-08 11:16:33 -04:00
Stefan Pintilie 6c4b40def7 [PowerPC][Future] Add Support For Functions That Do Not Use A TOC.
On PowerPC most functions require a valid TOC pointer.

This is the case because either the function itself needs to use this
pointer to access the TOC or because other functions that are called
from that function expect a valid TOC pointer in the register R2.
The main exception to this is leaf functions that do not access the TOC
since they are guaranteed not to need a valid TOC pointer.

This patch introduces a feature that will allow more functions to not
require a valid TOC pointer in R2.

Differential Revision: https://reviews.llvm.org/D73664
2020-04-08 08:07:35 -05:00
Matt Arsenault 6011627f51 CodeGen: More conversions to use Register 2020-04-07 18:54:36 -04:00
Matt Arsenault aa26dd9858 CodeGen: Use Register in more places 2020-04-07 15:59:40 -04:00
Nemanja Ivanovic ecd8435483 [NFC][PowerPC] Fix register class for patterns using XXPERMDIs
There are a few patterns where we use a superclass for inputs to this
instruction rather than the correct class. This can sometimes lead to
unncessary copies.
2020-04-07 14:06:08 -05:00
David Tenty b9245f14b7 [NFC][PowerPC] Cleanup 64-bit and Darwin CalleeSavedRegs
Summary:
- Remove the no longer used Darwin CalleeSavedRegs
- Combine the SVR464 callee saved regs and AIX64 since the two are (and should be) identical into PPC64
- Update tests for 64-bit CSR change

Reviewers: sfertile, ZarkoCA, cebowleratibm, jasonliu, #powerpc

Reviewed By: sfertile

Subscribers: wuzish, nemanjai, hiraditya, kbarton, shchenz, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D77235
2020-04-07 11:49:10 -04:00
Chris Bowler d6ea82d11c [AIX][PPC] Implement by-val caller arguments in multiple registers
Differential Revision: https://reviews.llvm.org/D76380
2020-04-06 11:06:51 -04:00
Matt Arsenault 30ebafaa56 CodeGen: Convert some TII hooks to use Register 2020-04-03 14:52:54 -04:00
jasonliu d65557d15d [NFC][XCOFF][AIX] Refactor get/setContainingCsect
Summary:
For current architect, we always require setContainingCsect to be
called on every MCSymbol got used in XCOFF context.
This is very hard to achieve because symbols gets created everywhere
 and other MCSymbol types(ELF, COFF) do not have similar rules.
It's very easy to miss setting the containing csect, and we would
need to add a lot of XCOFF specialized code around some common code area.

This patch intendeds to do
1. Rely on getFragment().getParent() to get csect from labels.
2. Only use get/setRepresentedCsect (was get/setContainingCsect)
if symbol itself represents a csect.

Reviewers: DiggerLin, hubert.reinterpretcast, daltenty

Differential Revision: https://reviews.llvm.org/D77080
2020-04-03 13:33:12 +00:00
Qiu Chaofan 71f1ab5354 [PowerPC] Remove unnecessary XSRSP instruction
MI peephole will remove unnecessary FRSP instructions. This patch
removes such unnecessary XSRSP.

Reviewed By: steven.zhang

Differential Revision: https://reviews.llvm.org/D77208
2020-04-03 11:05:14 +08:00
Fangrui Song cbd3969e8c [PPCInstPrinter] Delete an unneeded overload of printBranchOperand. NFC
It was added by D76591 for migration purposes (not all
printBranchOperand users have migrated to the overload with `uint64_t Address`).
Now that all have been migrated, the parameter can go away.
2020-04-01 22:45:25 -07:00
Fangrui Song 85adce3d73 [PPCInstPrinter] Change B to print the target address in hexadecimal form
Follow-up of D76591 and D76907
2020-04-01 22:38:24 -07:00
Guillaume Chatelet 1dffa2550b [Alignment][NFC] Transition to MachineFrameInfo::getObjectAlign()
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, sdardis, nemanjai, jvesely, nhaehnle, hiraditya, kbarton, jrtc27, atanasyan, kerbowa, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D77215
2020-04-01 14:08:28 +00:00
Guillaume Chatelet c7468c1696 [Alignment][NFC] Use Align in SelectionDAG::getMemIntrinsicNode
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: jholewinski, nemanjai, hiraditya, kbarton, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D77149
2020-04-01 09:32:05 +00:00
Kai Luo 8eb40e41f6 [PowerPC] Don't generate ST_VSR_SCAL_INT if power8-vector is disabled
Summary:
In https://bugs.llvm.org/show_bug.cgi?id=45297, it fails selecting
instructions for `PPCISD::ST_VSR_SCAL_INT`. The reason it generate the
`PPCISD::ST_VSR_SCAL_INT` with `-power8-vector` in IR is PPC's
combiner checks `hasP8Altivec` rather than `hasP8Vector`. This patch
should resolve PR45297.

Differential Revision: https://reviews.llvm.org/D76773
2020-04-01 02:15:25 +00:00
Fangrui Song 4af7560b37 [PPCInstPrinter] Print conditional branches as `bt 2, $target` instead of `bt 2, .+$imm`
Follow-up of D76591.

Reviewed By: #powerpc, sfertile

Differential Revision: https://reviews.llvm.org/D76907
2020-03-31 15:05:38 -07:00
Guillaume Chatelet c9d5c19597 [Alignment][NFC] Transitionning more getMachineMemOperand call sites
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, dylanmckay, sdardis, nemanjai, jvesely, nhaehnle, hiraditya, kbarton, jrtc27, atanasyan, Jim, kerbowa, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D77121
2020-03-31 08:36:18 +00:00
QingShan Zhang 4eeb56d088 [PowerPC] Don't do the folding if the operand is R0/X0
We have this transformation in PowerPC peephole:

Replace instruction:
  renamable $x28 = ADDI8 renamable $x7, -8
  renamable $x28 = ADD8 killed renamable $x28, renamable $x0
  STFD killed renamable $f0, -8, killed renamable $x28 :: (store 8 into %ir._ind_cast99.epil)
with:
  renamable $x28 = ADDI8 renamable $x7, -16
  STFDX killed renamable $f0, $x0, killed $x28 :: (store 8 into %ir._ind_cast99.epil)

It is invalid as the '$x0' in STFDX is constant 0, not register r0.

Reviewed By: Nemanjai

Differential Revision: https://reviews.llvm.org/D77034
2020-03-31 02:50:19 +00:00
Guillaume Chatelet bdf77209b9 [Alignment][NFC] Use Align version of getMachineMemOperand
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: jyknight, sdardis, nemanjai, hiraditya, kbarton, fedor.sergeev, asb, rbar, johnrusso, simoncook, sabuasal, niosHD, jrtc27, MaskRay, zzheng, edward-jones, atanasyan, rogfer01, MartinMosbeck, brucehoult, the_o, jfb, PkmX, jocewei, Jim, lenary, s.egerton, pzheng, sameer.abuasal, apazos, luismarques, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D77059
2020-03-30 15:46:27 +00:00
Fangrui Song fc93787d7e [MC][PowerPC] Make .reloc support arbitrary relocation types
Generalizes ad7199f3e6 (R_PPC_NONE/R_PPC64_NONE).
2020-03-28 17:04:31 -07:00
diggerlin 9c20f09985 [AIX] Address comment https://reviews.llvm.org/D76162#inline-701237
SUMMARY:

Address clang format issue:

"clang format this block, I don't think the spaces are aligned correctly."

Subscribers: wuzish, nemanjai, hiraditya

Differential Revision: https://reviews.llvm.org/D76162
2020-03-27 16:21:53 -04:00
Guillaume Chatelet 74eac9031a [Alignment][NFC] MachineMemOperand::getAlign/getBaseAlign
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
2020-03-27 15:49:13 +00:00
Fangrui Song 6728a9ae19 [MCInstPrinter] Add parameter `Address` to printCustomAliasOperand. NFC
Follow-up of D72172 and llvmorg-11-init-6896-gb3cc5dcef0f.
2020-03-27 00:38:20 -07:00
Fangrui Song b3cc5dcef0 [MCInstPrinter] Add parameter `Address` to MCInstPrinter::printAliasInstr. NFC
Follow-up of D72172.
2020-03-27 00:03:32 -07:00
diggerlin fdfe411e7c [AIX] discard the label in the csect of function description and use qualname for linkage
SUMMARY:

SUMMARY
for a source file  "test.c"

void foo() {};

llc will generate assembly code as (assembly patch)
     .globl  foo
     .globl  .foo
     .csect foo[DS]
foo:

        .long   .foo
        .long   TOC[TC0]
        .long   0

   and symbol table as (xcoff object file)
   [4]     m   0x00000004     .data     1  unamex                    foo
   [5]     a4  0x0000000c       0    0     SD       DS    0    0
   [6]     m   0x00000004     .data     1  extern                    foo
   [7]     a4  0x00000004       0    0     LD       DS    0    0

   After first patch, the assembly will be as

        .globl  foo[DS]                 # -- Begin function foo
        .globl  .foo
        .align  2
        .csect foo[DS]
        .long   .foo
        .long   TOC[TC0]
        .long   0

    and symbol table will as
   [6]     m   0x00000004     .data     1  extern                    foo
   [7]     a4  0x00000004       0    0     DS      DS    0    0
Change the code for the assembly path and xcoff objectfile patch for llc.

Reviewers: Jason Liu
Subscribers: wuzish, nemanjai, hiraditya

Differential Revision: https://reviews.llvm.org/D76162
2020-03-26 15:46:52 -04:00
Guillaume Chatelet b727aabcb8 [Alignment][NFC] Use llvmTargetFrameLowering::getStackAlign
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

Reviewed By: courbet

Subscribers: wuzish, arsenm, jyknight, nemanjai, jvesely, nhaehnle, hiraditya, kbarton, fedor.sergeev, jrtc27, kerbowa, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D76613
2020-03-26 18:15:53 +00:00
Justin Hibbits 459e8e9488 [PowerPC]: Don't allow r0 as a target for LD_GOT_TPREL_L/32
Summary:
The linker is free to relax this (relocation R_PPC_GOT_TPREL16) against
R_PPC_TLS, if it sees fit (initial exec to local exec).  If r0 is used,
this can generate execution-invalid code (converts to 'addi %rX, %r0,
FOO, which translates in PPC-lingo to li %rX, FOO).  Forbid this
instead.

This fixes static binaries using locales on FreeBSD/powerpc
(tested on FreeBSD/powerpcspe).

Reviewed By: nemanjai
Differential Revision: https://reviews.llvm.org/D76662
2020-03-26 10:59:28 -05:00
Fangrui Song 3eef47407b [PPCInstPrinter] Change printBranchOperand(calltarget) to print the target address in hexadecimal form
```
// llvm-objdump -d output (before)
0: bl .-4
4: bl .+0
8: bl .+4

// llvm-objdump -d output (after) ; GNU objdump -d
0: bl 0xfffffffc / bl 0xfffffffffffffffc
4: bl 0x4
8: bl 0xc
```

Many Operand's are not annotated as OPERAND_PCREL.
They are not affected (e.g. `b .+67108860`). I plan to fix them in future patches.

Modified test/tools/llvm-objdump/ELF/PowerPC/branch-offset.s to test
address space wraparound for powerpc32 and powerpc64.

Reviewed By: sfertile, jhenderson

Differential Revision: https://reviews.llvm.org/D76591
2020-03-26 08:32:29 -07:00
Fangrui Song 5fad05e80d [MCInstPrinter] Pass `Address` parameter to MCOI::OPERAND_PCREL typed operands. NFC
Follow-up of D72172 and D72180

This patch passes `uint64_t Address` to print methods of PC-relative
operands so that subsequent target specific patches can change
`*InstPrinter::print{Operand,PCRelImm,...}` to customize the output.

Add MCInstPrinter::PrintBranchImmAsAddress which is set to true by
llvm-objdump.

```
// Current llvm-objdump -d output
aarch64: 20000: bl #0
ppc:     20000: bl .+4
x86:     20000: callq 0

// Ideal output
aarch64: 20000: bl 0x20000
ppc:     20000: bl 0x20004
x86:     20000: callq 0x20005

// GNU objdump -d. The lack of 0x is not ideal because the result cannot be re-assembled
aarch64: 20000: bl 20000
ppc:     20000: bl 0x20004
x86:     20000: callq 20005
```

In `lib/Target/X86/X86GenAsmWriter1.inc` (generated by `llvm-tblgen -gen-asm-writer`):

```
   case 12:
     // CALL64pcrel32, CALLpcrel16, CALLpcrel32, EH_SjLj_Setup, JCXZ, JECXZ, J...
-    printPCRelImm(MI, 0, O);
+    printPCRelImm(MI, Address, 0, O);
     return;
```

Some targets have 2 `printOperand` overloads, one without `Address` and
one with `Address`. They should annotate derived `Operand` properly with
`let OperandType = "OPERAND_PCREL"`.

Reviewed By: jhenderson

Differential Revision: https://reviews.llvm.org/D76574
2020-03-26 08:21:15 -07:00
Kang Zhang 4673699a47 [PowerPC] Remove the repeated definition for some InstAlias for mtspr/mfspr
Summary:
Below InstAlias have been redefined, this patch is to remove the repeated
definition.
mtdec/mfdec mtsdr1/mfsdr1 mtsrr0/mfsrr0 mtsrr1/mfsrr1 mtasr

Reviewed By: nemanjai, steven.zhang

Differential Revision: https://reviews.llvm.org/D75821
2020-03-26 09:58:30 +00:00
QingShan Zhang 1ef7bf4121 [PowerPC] Improve the way legalize mul for v8i16 and add pattern to match mul + add
We can legalize the operation MUL for v8i16 with instruction (vmladduhm A, B, 0)
if altivec enabled. Now, it is set as custom and expand it later, which is not
the right way. And then, we can add the pattern to match the mul + add with (vmladduhm A, B, C)

Reviewed By: Nemanjai

Differential Revision: https://reviews.llvm.org/D76751
2020-03-26 04:46:49 +00:00
Sean Fertile 3282d875d6 [PowerPC][AIX] ByVal formal arguments in a single register.
Adds support for passing ByVal formal arguments as long as they fit in a
single register.

Differential Revision: https://reviews.llvm.org/D76401
2020-03-25 11:09:40 -04:00
Chen Zheng 9d07d91fb6 [PowerPC] fix a typo in commit 3f85134d71
Implement target hook isProfitableToHoist - typo fix.
2020-03-24 01:56:15 -04:00
Nemanja Ivanovic bfa9ce1cb2 [PowerPC] Improve handling of some BUILD_VECTOR nodes
An analysis of real world code turned up a number of patterns with BUILD_VECTOR
of nodes resulting from operations on extracted vector elements for which we
produce poor code. This addresses those cases. No attempt is made for
completeness as that would entail a large amount of work for something that
there is no evidence of in real code.

Differential revision: https://reviews.llvm.org/D72660
2020-03-23 17:34:29 -05:00
Justin Hibbits f0990e104b [PowerPC]: e500 target can't use lwsync, use msync instead
The e500 core has a silicon bug that triggers an illegal instruction
program trap on any sync other than msync.  Other cores will typically
ignore illegal sync types, and the documentation even implies that the
'illegal' bits are ignored.

Address this hardware deficiency by only using msync, like the PPC440.

Differential Revision:  https://reviews.llvm.org/D76614
2020-03-23 17:15:27 -05:00
Guillaume Chatelet 3ba550a05a [Alignment][NFC] Use TFL::getStackAlign()
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: dylanmckay, sdardis, nemanjai, hiraditya, kbarton, asb, rbar, johnrusso, simoncook, sabuasal, niosHD, jrtc27, MaskRay, zzheng, edward-jones, atanasyan, rogfer01, MartinMosbeck, brucehoult, the_o, PkmX, jocewei, Jim, lenary, s.egerton, pzheng, sameer.abuasal, apazos, luismarques, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D76551
2020-03-23 13:48:29 +01:00
Fangrui Song 85c30f3374 [X86] Reland D71360 Clean up UseInitArray initialization for X86ELFTargetObjectFile
-fuse-init-array is now the CC1 default but TargetLoweringObjectFileELF::UseInitArray still defaults to false.
The following two unknown OS target triples continue using .ctors/.dtors because InitializeELF is not called.

clang -target i386 -c a.c
clang -target x86_64 -c a.c

This cleanup fixes this as a bonus.

X86SpeculativeLoadHardeningPass::tracePredStateThroughCall can call
MCContext::createTempSymbol before TargetLoweringObjectFileELF::Initialize().
We need to call TargetLoweringObjectFileELF::Initialize() ealier.

test/CodeGen/X86/speculative-load-hardening-indirect.ll

Differential Revision: https://reviews.llvm.org/D71360
2020-03-20 21:57:34 -07:00
Eric Christopher fc7233d774 Temporarily Revert "[X86] Reland D71360 Clean up UseInitArray initialization for X86ELFTargetObjectFile"
as it's causing msan failures.

This reverts commit 7899fe9da8.
2020-03-20 17:36:12 -07:00
Fangrui Song 7899fe9da8 [X86] Reland D71360 Clean up UseInitArray initialization for X86ELFTargetObjectFile
UseInitArray is now the CC1 default but TargetLoweringObjectFileELF::UseInitArray still defaults to false.
The following two unknown OS target triples continue using .ctors/.dtors because InitializeELF is not called.

clang -target i386 -c a.c
clang -target x86_64 -c a.c

This cleanup fixes this as a bonus.

Differential Revision: https://reviews.llvm.org/D71360
2020-03-20 11:18:36 -07:00
Chen Zheng 3f85134d71 [PowerPC] implement target hook isProfitableToHoist
On Powerpc fma is faster than fadd + fmul for some types,
(PPCTargetLowering::isFMAFasterThanFMulAndFAdd). we should implement target
hook isProfitableToHoist to prevent simplifyCFGpass from breaking fma
pattern by hoisting fmul to predecessor block.

Reviewed By: nemanjai

Differential Revision: https://reviews.llvm.org/D76207
2020-03-19 00:17:25 -04:00
Chen Zheng aacf022cd5 [PowerPC] add IR level isFMAFasterThanFMulAndFAdd - NFC
And also refactor legacy MIR level isFMAFasterThanFMulAndFAdd.

Reviewed By: steven.zhang

Differential Revision: https://reviews.llvm.org/D76265
2020-03-18 23:24:40 -04:00
Nemanja Ivanovic e009fad342 [PowerPC] Remove UB from PPCInstrInfo when handling rotates fed by constants
As pointed out in https://bugs.llvm.org/show_bug.cgi?id=45232 this code can
end up shifting a 64-bit unsigned value left by 64 bits. Althought this works
as expected on some platforms it is definitely UB. This patch removes the UB
and adds the associated test case.

Fixes: https://bugs.llvm.org/show_bug.cgi?id=45232
2020-03-18 13:40:39 -05:00
Chris Bowler c21866476e [PowerPC][AIX] Implement by-val caller arguments in a single register.
This is the first of a series of patches that adds caller support for
by-value arguments. This patch add support for arguments that are passed in a
single GPR.

There are 3 limitation cases:
-The by-value argument is larger than a single register.
-There are no remaining GPRs even though the by-value argument would
otherwise fit in a single GPR.
-The by-value argument requires alignment greater than register width.

Future patches will be required to add support for these cases as well
as for the callee handling (in LowerFormalArguments_AIX) that
corresponds to this work.

Differential Revision: https://reviews.llvm.org/D75863
2020-03-18 10:57:28 -04:00
Guillaume Chatelet d000655a8c [Alignment][NFC] Deprecate getMaxAlignment
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: jholewinski, arsenm, dschuff, jyknight, sdardis, nemanjai, jvesely, nhaehnle, sbc100, jgravelle-google, hiraditya, aheejin, kbarton, fedor.sergeev, asb, rbar, johnrusso, simoncook, sabuasal, niosHD, jrtc27, MaskRay, zzheng, edward-jones, atanasyan, rogfer01, MartinMosbeck, brucehoult, the_o, PkmX, jocewei, Jim, lenary, s.egerton, pzheng, sameer.abuasal, apazos, luismarques, kerbowa, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D76348
2020-03-18 14:48:45 +01:00
QingShan Zhang b83490bdb7 [PowerPC] Fix a typo of the condition of checking the fusion candidate 2020-03-17 10:04:18 +00:00
QingShan Zhang 0b126eec6d [NFC][PowerPC] Simplify the logic in lower select_cc
The logic in select_cc is messy and hard to follow. This is a NFC patch to simplify the logic.

Differential Revision: https://reviews.llvm.org/D75834
2020-03-17 03:47:39 +00:00