Commit Graph

477 Commits

Author SHA1 Message Date
Francis Visoiu Mistrih d42289e291 [RISCV] Fix uninitialized variable after call to evaluateConstantImm
For llvm/test/MC/RISCV/rv64i-aliases-invalid.s, UBSan reports:

lib/Target/RISCV/AsmParser/RISCVAsmParser.cpp:371:9: runtime error:
load of value 3879186881, which is not a valid value for type
'RISCVMCExpr::VariantKind'
SUMMARY: UndefinedBehaviorSanitizer: undefined-behavior
lib/Target/RISCV/AsmParser/RISCVAsmParser.cpp:371:9 in

It turns out that evaluateConstantImm does not set `VK` and it remains
unitialized when doing comparisons in `isImmXLenLI()`.

Differential Revision: https://reviews.llvm.org/D65347

llvm-svn: 367230
2019-07-29 15:52:13 +00:00
Hsiangkai Wang 18ccfadd46 [DebugInfo] Generate fixups as emitting DWARF .debug_frame/.eh_frame.
It is necessary to generate fixups in .debug_frame or .eh_frame as
relaxation is enabled due to the address delta may be changed after
relaxation.

There is an opcode with 6-bits data in debug frame encoding. So, we
also need 6-bits fixup types.

Differential Revision: https://reviews.llvm.org/D58335

llvm-svn: 366524
2019-07-19 02:03:34 +00:00
Hsiangkai Wang 657277e0f1 Revert "[DebugInfo] Generate fixups as emitting DWARF .debug_frame/.eh_frame."
This reverts commit 17e3cbf5fe656483d9016d0ba9e1d0cd8629379e.

llvm-svn: 366444
2019-07-18 15:06:50 +00:00
Hsiangkai Wang e43ce1a958 [DebugInfo] Generate fixups as emitting DWARF .debug_frame/.eh_frame.
It is necessary to generate fixups in .debug_frame or .eh_frame as
relaxation is enabled due to the address delta may be changed after
relaxation.

There is an opcode with 6-bits data in debug frame encoding. So, we
also need 6-bits fixup types.

Differential Revision: https://reviews.llvm.org/D58335

llvm-svn: 366442
2019-07-18 14:47:34 +00:00
Alex Bradbury b8d352a08b [RISCV] Reset NoPHIS MachineFunctionProperty in emitSelectPseudo
We insered PHIS were there were none before, so the property must be
reset. This error was found on an EXPENSIVE_CHECKS build.

llvm-svn: 366412
2019-07-18 07:52:41 +00:00
Alex Bradbury 8aba95d64c [RISCV] Avoid signed integer overflow UB in RISCVMatInt::generateInstSeq
Found by UBSan.

llvm-svn: 366398
2019-07-18 04:02:58 +00:00
Alex Bradbury ad73a436dc [RISCV] Don't acccess an invalidated iterator in RISCVInstrInfo::removeBranch
Issue found by ASan.

llvm-svn: 366397
2019-07-18 03:23:47 +00:00
Alex Bradbury 1ffceaa543 [RISCV] Match GNU tools canonical JALR and add aliases
The canonical GNU form of JALR resembles a load/store instruction rather
than placing the immediate offset as a separate argument, so match this
behaviour. Also add parser-only aliases for the three-operand form, and
add other shorter aliases also emitted by GNU tools.

Differential Revision: https://reviews.llvm.org/D55277
Patch by James Clarke.

llvm-svn: 366179
2019-07-16 04:56:43 +00:00
Alex Bradbury bb479ca311 [RISCV] Avoid overflow when determining number of nops for code align
RISCVAsmBackend::shouldInsertExtraNopBytesForCodeAlign() assumed that the
align specified would be greater than or equal to the minimum nop length, but
that is not always the case - for example if a user specifies ".align 0" in
assembly.

Differential Revision: https://reviews.llvm.org/D63274
Patch by Edward Jones.

llvm-svn: 366176
2019-07-16 04:40:25 +00:00
Alex Bradbury e9ad0cf6cf [RISCV] Fix a potential issue in shouldInsertFixupForCodeAlign()
The bool result of shouldInsertExtraNopBytesForCodeAlign() is not checked but
the returned nop count is unconditionally read even though it could be
uninitialized.

Differential Revision: https://reviews.llvm.org/D63285
Patch by Edward Jones.

llvm-svn: 366175
2019-07-16 04:37:19 +00:00
Alex Bradbury ef8577ef98 [RISCV][NFC] Split PseudoCALL pattern out from instruction
Since PseudoCALL defines AsmString, it can be generated from assembly,
and so code-gen patterns should be defined separately to be consistent
with the style of the RISCV backend. Other pseudo-instructions exist
that have code-gen patterns defined directly, but these instructions are
purely for code-gen and cannot be written in assembly.

Differential Revision: https://reviews.llvm.org/D64012
Patch by James Clarke.

llvm-svn: 366174
2019-07-16 03:56:45 +00:00
Alex Bradbury a3c7b27419 [RISCV][NFC] Fix HasStedExtA -> HasStdExtA typo in comment
Differential Revision: https://reviews.llvm.org/D64011
Patch by James Clarke.

llvm-svn: 366173
2019-07-16 03:54:08 +00:00
Alex Bradbury 4ac0b9be23 [RISCV] Make RISCVELFObjectWriter::getRelocType check IsPCRel
Previously, this function didn't check the IsPCRel argument. But doing so is a
useful check for errors, and also seemingly necessary for FK_Data_4 (which we
produce a R_RISCV_32_PCREL relocation for if IsPCRel).

Other than R_RISCV_32_PCREL, this should be NFC. Future exception handling
related patches will include tests that capture this behaviour.

llvm-svn: 366172
2019-07-16 03:47:34 +00:00
Sam Elliott fafec5155e [RISCV] Allow parsing dot '.' in assembly
Summary:
Useful for jumps, such as `j .`.

I am not sure who should review this. Do not hesitate to change the reviewers if needed.

Reviewers: asb, jrtc27, lenary

Reviewed By: lenary

Subscribers: MaskRay, lenary, hiraditya, rbar, johnrusso, simoncook, apazos, sabuasal, niosHD, kito-cheng, shiva0217, zzheng, edward-jones, rogfer01, MartinMosbeck, brucehoult, the_o, rkruppe, PkmX, jocewei, psnobl, benna, Jim, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D63669

Patch by John LLVM (JohnLLVM)

llvm-svn: 365881
2019-07-12 08:36:07 +00:00
Sam Elliott 114d2db49b [RISCV] Fix ICE in isDesirableToCommuteWithShift
Summary:
There was an error being thrown from isDesirableToCommuteWithShift in
some tests. This was tracked down to the method being called before
legalisation, with an extended value type, not a machine value type.

In the case I diagnosed, the error was only hit with an instruction sequence
involving `i24`s in the add and shift. `i24` is not a Machine ValueType, it is
instead an Extended ValueType which was causing the issue.

I have added a test to cover this case, and fixed the error in the callback.

Reviewers: asb, luismarques

Reviewed By: asb

Subscribers: hiraditya, rbar, johnrusso, simoncook, apazos, sabuasal, niosHD, kito-cheng, shiva0217, jrtc27, MaskRay, zzheng, edward-jones, rogfer01, MartinMosbeck, brucehoult, the_o, rkruppe, PkmX, jocewei, psnobl, benna, Jim, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D64425

llvm-svn: 365511
2019-07-09 16:24:16 +00:00
Alex Bradbury e0831dac0c [RISCV] Fix RISCVTTIImpl::getIntImmCost for immediates where getMinSignedBits() > 64
APInt::getSExtValue will assert if getMinSignedBits() > 64. This can happen,
for instance, if examining an i128. Avoid this assertion by checking
Imm.getMinSignedBits() <= 64 before doing
getTLI()->isLegalAddImmediate(Imm.getSExtValue()). We could directly check
getMinSignedBits() <= 12 but it seems better to reuse the isLegalAddImmediate
helper for this.

Differential Revision: https://reviews.llvm.org/D64390

llvm-svn: 365462
2019-07-09 10:56:18 +00:00
Alex Bradbury 0b9addb8c0 [RISCV] Specify registers used in DWARF exception handling
Defines RISCV registers for getExceptionPointerRegister() and
getExceptionSelectorRegister().

Differential Revision: https://reviews.llvm.org/D63411
Patch by Edward Jones.
Modified by Alex Bradbury to add CHECK lines to exception-pointer-register.ll.

llvm-svn: 365301
2019-07-08 09:16:47 +00:00
Alex Bradbury e1e036a33b [RISCV] Support z and i operand modifiers
Differential Revision: https://reviews.llvm.org/D57792
Patch by James Clarke.

llvm-svn: 365291
2019-07-08 05:00:26 +00:00
Sam Elliott b2c9eed0d7 [RISCV] Support @llvm.readcyclecounter() Intrinsic
On RISC-V, the `cycle` CSR holds a 64-bit count of the number of clock
cycles executed by the core, from an arbitrary point in the past. This
matches the intended semantics of `@llvm.readcyclecounter()`, which we
currently leave to the default lowering (to the constant 0).

With this patch, we will now correctly lower this intrinsic to the
intended semantics, using the user-space instruction `rdcycle`. On
64-bit targets, we can directly lower to this instruction.

On 32-bit targets, we need to do more, as `rdcycle` only returns the low
32-bits of the `cycle` CSR. In this case, we perform a custom lowering,
based on the PowerPC lowering, using `rdcycleh` to obtain the high
32-bits of the `cycle` CSR. This custom lowering inserts a new basic
block which detects overflow in the high 32-bits of the `cycle` CSR
during reading (because multiple instructions are required to read). The
emitted assembly matches the suggested assembly in the RISC-V
specification.

Differential Revision: https://reviews.llvm.org/D64125

llvm-svn: 365201
2019-07-05 12:35:21 +00:00
Sam Elliott 6884d5e040 [RISCV][NFC] Replace hard-coded CSR duplication with symbolic references
Reviewers: asb, lenary

Reviewed By: asb, lenary

Subscribers: MaskRay, hiraditya, rbar, johnrusso, simoncook, apazos, sabuasal, niosHD, kito-cheng, shiva0217, zzheng, edward-jones, rogfer01, MartinMosbeck, brucehoult, the_o, rkruppe, PkmX, jocewei, psnobl, benna, Jim, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D64139

Patch by James Clarke (jrtc27)

llvm-svn: 365195
2019-07-05 12:16:40 +00:00
Fangrui Song 6fa850c4fe [RISCV] Delete a ctor that is commented out. NFC
llvm-svn: 365175
2019-07-05 08:25:14 +00:00
Fangrui Song 92e78b7bed [RISCV] Add break; to the last switch case
As suggested by jrtc27 in the post-commit review of D60528.

llvm-svn: 364746
2019-07-01 11:41:07 +00:00
Lewis Revill cf74881329 [RISCV] Add pseudo instruction for calls with explicit register
This patch adds the PseudoCALLReg instruction which allows using an
explicit register operand as the destination for the return address.

GCC can successfully parse this form of the call instruction, which
would be used for calls to functions which do not use ra as the return
address register, such as the __riscv_save libcalls. This patch forms
the first part of an implementation of -msave-restore for RISC-V.

Differential Revision: https://reviews.llvm.org/D62685

llvm-svn: 364403
2019-06-26 10:35:58 +00:00
Matt Arsenault e3a676e9ad CodeGen: Introduce a class for registers
Avoids using a plain unsigned for registers throughoug codegen.
Doesn't attempt to change every register use, just something a little
more than the set needed to build after changing the return type of
MachineOperand::getReg().

llvm-svn: 364191
2019-06-24 15:50:29 +00:00
Sam Elliott 96c8bc7956 [RISCV] Add RISCV-specific TargetTransformInfo
Summary:
LLVM Allows Targets to provide information that guides optimisations
made to LLVM IR. This is done with callbacks on a TargetTransformInfo object.

This patch adds a TargetTransformInfo class for RISC-V. This will allow us to
implement RISC-V specific callbacks as they become necessary.

This commit also adds the getIntImmCost callbacks, and tests them with a simple
constant hoisting test. Our immediate costs are on the conservative side, for
the moment, but we prevent hoisting in most circumstances anyway.

Previous review was on D63007

Reviewers: asb, luismarques

Reviewed By: asb

Subscribers: ributzka, MaskRay, llvm-commits, Jim, benna, psnobl, jocewei, PkmX, rkruppe, the_o, brucehoult, MartinMosbeck, rogfer01, edward-jones, zzheng, jrtc27, shiva0217, kito-cheng, niosHD, sabuasal, apazos, simoncook, johnrusso, rbar, hiraditya, mgorny

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D63433

llvm-svn: 364046
2019-06-21 13:36:09 +00:00
Lewis Revill 18737e81eb [RISCV] Allow parsing immediates that use tilde & exclaim
This patch allows immediates (and CSR alias immediates) which start with
a tilde token or an exclaim (!) token to be parsed as intended.

Differential Revision: https://reviews.llvm.org/D57320

llvm-svn: 363783
2019-06-19 10:27:24 +00:00
Lewis Revill 218aa0edb1 [RISCV] Fix failure to parse parenthesized immediates
Since the parser attempts to parse an operand as a register with
parentheses before parsing it as an immediate, immediates in
parentheses should not be parsed by parseRegister. However in the case
where the immediate does not start with an identifier, the LParen is not
unlexed and so the RParen causes an unexpected token error.

This patch adds the missing UnLex, and modifies the existing UnLex to
not use a buffered token, as it should always be unlexing an LParen.

Differential Revision: https://reviews.llvm.org/D57319

llvm-svn: 363782
2019-06-19 10:11:13 +00:00
Lewis Revill 39263ac5d1 [RISCV] Add lowering of global TLS addresses
This patch adds lowering for global TLS addresses for the TLS models of
InitialExec, GlobalDynamic, LocalExec and LocalDynamic.

LocalExec support required using a 4-operand add instruction, which uses
the fourth operand to express a relocation on the symbol. The necessary
fixup is emitted when the instruction is emitted.

Differential Revision: https://reviews.llvm.org/D55305

llvm-svn: 363771
2019-06-19 08:40:59 +00:00
Sam Elliott 9f155bc6e5 [RISCV] Prevent re-ordering some adds after shifts
Summary:
DAGCombine will normally turn a `(shl (add x, c1), c2)` into `(add (shl x, c2), c1 << c2)`, where `c1` and `c2` are constants. This can be prevented by a callback in TargetLowering.

On RISC-V, materialising the constant `c1 << c2` can be more expensive than materialising `c1`, because materialising the former may take more instructions, and may use a register, where materialising the latter would not.

This patch implements the hook in RISCVTargetLowering to prevent this transform, in the cases where:
- `c1` fits into the immediate field in an `addi` instruction.
- `c1` takes fewer instructions to materialise than `c1 << c2`.

In future, DAGCombine could do the check to see whether `c1` fits into an add immediate, which might simplify more targets hooks than just RISC-V.

Reviewers: asb, luismarques, efriedma

Reviewed By: asb

Subscribers: xbolva00, lebedev.ri, craig.topper, lewis-revill, Jim, hiraditya, rbar, johnrusso, simoncook, apazos, sabuasal, niosHD, kito-cheng, shiva0217, jrtc27, zzheng, edward-jones, rogfer01, MartinMosbeck, brucehoult, the_o, rkruppe, PkmX, jocewei, psnobl, benna, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D62857

llvm-svn: 363736
2019-06-18 20:38:08 +00:00
Lewis Revill 74c8364954 [RISCV] Lower calls through PLT
This patch adds support for generating calls through the procedure
linkage table where required for a given ExternalSymbol or GlobalAddress
callee.

Differential Revision: https://reviews.llvm.org/D55304

llvm-svn: 363686
2019-06-18 14:29:45 +00:00
Luis Marques 2e46312ffd [DAGCombiner] [CodeGenPrepare] More comprehensive GEP splitting
Some GEPs were not being split, presumably because that split would just be 
undone by the DAGCombiner. Not performing those splits can prevent important 
optimizations, such as preventing the element indices / member offsets from 
being (partially) folded into load/store instruction immediates. This patch:

- Makes the splits also occur in the cases where the base address and the GEP 
  are in the same BB.
- Ensures that the DAGCombiner doesn't reassociate them back again.

Differential Revision: https://reviews.llvm.org/D60294

llvm-svn: 363544
2019-06-17 10:54:12 +00:00
Fangrui Song 44cc4e9351 [RISCV] Simplify RISCVAsmBackend::writeNopData(). NFC
llvm-svn: 363486
2019-06-15 06:14:15 +00:00
Hsiangkai Wang 04ddf39b44 [RISCV] Add CFI directives for RISCV prologue/epilog.
In order to generate correct debug frame information, it needs to
generate CFI information in prologue and epilog.

Differential Revision: https://reviews.llvm.org/D61773

llvm-svn: 363120
2019-06-12 03:04:22 +00:00
Lewis Revill a5240361dd [RISCV] Add lowering of addressing sequences for PIC
This patch allows lowering of PIC addresses by using PC-relative
addressing for DSO-local symbols and accessing the address through the
global offset table for non-DSO-local symbols.

Differential Revision: https://reviews.llvm.org/D55303

llvm-svn: 363058
2019-06-11 12:57:47 +00:00
Lewis Revill 28a5cadb3a [RISCV] Lower inline asm constraints I, J & K for RISC-V
This validates and lowers arguments to inline asm nodes which have the
constraints I, J & K, with the following semantics (equivalent to GCC):

I: Any 12-bit signed immediate.
J: Immediate integer zero only.
K: Any 5-bit unsigned immediate.

Differential Revision: https://reviews.llvm.org/D54093

llvm-svn: 363054
2019-06-11 12:42:13 +00:00
Tom Stellard 4b0b26199b Revert CMake: Make most target symbols hidden by default
This reverts r362990 (git commit 374571301d)

This was causing linker warnings on Darwin:

ld: warning: direct access in function 'llvm::initializeEvexToVexInstPassPass(llvm::PassRegistry&)'
from file '../../lib/libLLVMX86CodeGen.a(X86EvexToVex.cpp.o)' to global weak symbol
'void std::__1::__call_once_proxy<std::__1::tuple<void* (&)(llvm::PassRegistry&),
std::__1::reference_wrapper<llvm::PassRegistry>&&> >(void*)' from file '../../lib/libLLVMCore.a(Verifier.cpp.o)'
means the weak symbol cannot be overridden at runtime. This was likely caused by different translation
units being compiled with different visibility settings.

llvm-svn: 363028
2019-06-11 03:21:13 +00:00
Tom Stellard 374571301d CMake: Make most target symbols hidden by default
Summary:
For builds with LLVM_BUILD_LLVM_DYLIB=ON and BUILD_SHARED_LIBS=OFF
this change makes all symbols in the target specific libraries hidden
by default.

A new macro called LLVM_EXTERNAL_VISIBILITY has been added to mark symbols in these
libraries public, which is mainly needed for the definitions of the
LLVMInitialize* functions.

This patch reduces the number of public symbols in libLLVM.so by about
25%.  This should improve load times for the dynamic library and also
make abi checker tools, like abidiff require less memory when analyzing
libLLVM.so

One side-effect of this change is that for builds with
LLVM_BUILD_LLVM_DYLIB=ON and LLVM_LINK_LLVM_DYLIB=ON some unittests that
access symbols that are no longer public will need to be statically linked.

Before and after public symbol counts (using gcc 8.2.1, ld.bfd 2.31.1):
nm before/libLLVM-9svn.so | grep ' [A-Zuvw] ' | wc -l
36221
nm after/libLLVM-9svn.so | grep ' [A-Zuvw] ' | wc -l
26278

Reviewers: chandlerc, beanz, mgorny, rnk, hans

Reviewed By: rnk, hans

Subscribers: Jim, hiraditya, michaelplatings, chapuni, jholewinski, arsenm, dschuff, jyknight, dylanmckay, sdardis, nemanjai, jvesely, nhaehnle, javed.absar, sbc100, jgravelle-google, aheejin, kbarton, fedor.sergeev, asb, rbar, johnrusso, simoncook, apazos, sabuasal, niosHD, jrtc27, zzheng, edward-jones, mgrang, atanasyan, rogfer01, MartinMosbeck, brucehoult, the_o, PkmX, jocewei, kristina, jsji, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D54439

llvm-svn: 362990
2019-06-10 22:12:56 +00:00
Sam Elliott f720647ddd [RISCV] Support Bit-Preserving FP in F/D Extensions
Summary:
This allows some integer bitwise operations to instead be performed by
hardware fp instructions. This is correct because the RISC-V spec
requires the F and D extensions to use the IEEE-754 standard
representation, and fp register loads and stores to be bit-preserving.

This is tested against the soft-float ABI, but with hardware float
extensions enabled, so that the tests also ensure the optimisation also
fires in this case.

Reviewers: asb, luismarques

Reviewed By: asb

Subscribers: hiraditya, rbar, johnrusso, simoncook, apazos, sabuasal, niosHD, kito-cheng, shiva0217, jrtc27, zzheng, edward-jones, rogfer01, MartinMosbeck, brucehoult, the_o, rkruppe, PkmX, jocewei, psnobl, benna, Jim, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D62900

llvm-svn: 362790
2019-06-07 12:20:14 +00:00
Lewis Revill 74927554e2 [RISCV] Support assembling TLS LA pseudo instructions
This patch adds the pseudo instructions la.tls.ie and la.tls.gd, used in
the initial-exec and global-dynamic TLS models respectively when
addressing a global. The pseudo instructions are expanded in the
assembly parser.

llvm-svn: 361499
2019-05-23 14:46:27 +00:00
Richard Trieu 51fc56d603 [RISCV] Create a TargetInfo header. NFC
Move the declarations of getThe<Name>Target() functions into a new header in
TargetInfo and make users of these functions include this new header.
This fixes a layering problem.

llvm-svn: 360732
2019-05-15 00:24:15 +00:00
Richard Trieu 00ecf67045 [RISCV] Move InstPrinter files to MCTargetDesc. NFC
For some targets, there is a circular dependency between InstPrinter and
MCTargetDesc.  Merging them together will fix this.  For the other targets,
the merging is to maintain consistency so all targets will have the same
structure

llvm-svn: 360505
2019-05-11 02:43:58 +00:00
Lewis Revill df3cb477a3 [RISCV] Support assembling %tls_{ie,gd}_pcrel_hi modifiers
This patch adds support for parsing and assembling the %tls_ie_pcrel_hi
and %tls_gd_pcrel_hi modifiers.

Differential Revision: https://reviews.llvm.org/D55342

llvm-svn: 358994
2019-04-23 14:46:13 +00:00
Luis Marques 20d2424016 [RISCV] Custom lower SHL_PARTS, SRA_PARTS, SRL_PARTS
When not optimizing for minimum size (-Oz) we custom lower wide shifts
(SHL_PARTS, SRA_PARTS, SRL_PARTS) instead of expanding to a libcall.

Differential Revision: https://reviews.llvm.org/D59477

llvm-svn: 358498
2019-04-16 14:38:32 +00:00
Roger Ferrer Ibanez b621f04135 [RISCV] Diagnose invalid second input register operand when using %tprel_add
RISCVMCCodeEmitter::expandAddTPRel asserts that the second operand must be
x4/tp. As we are not currently checking this in the RISCVAsmParser, the assert
is easy to trigger due to wrong assembly input.

This patch does a late check of this constraint.

An alternative could be using a singleton register class for x4/tp similar to
the current one for sp. Unfortunately it does not result in a good diagnostic.
Because add is an overloaded mnemonic, if no matching is possible, the
diagnostic of the first failing alternative seems to be used as the diagnostic
itself. This means that this case the %tprel_add is diagnosed as an invalid
operand (because the real add instruction only has 3 operands).

Differential Revision: https://reviews.llvm.org/D60528

llvm-svn: 358183
2019-04-11 15:13:12 +00:00
Shiva Chen 7cc03bd064 [RISCV] Put data smaller than eight bytes to small data section
Because of gp = sdata_start_address + 0x800, gp with signed twelve-bit offset
could covert most of the small data section. Linker relaxation could transfer
the multiple data accessing instructions to a gp base with signed twelve-bit
offset instruction.

Differential Revision: https://reviews.llvm.org/D57493

llvm-svn: 358150
2019-04-11 04:59:13 +00:00
Nick Desaulniers 5277b3ff25 [AsmPrinter] refactor to remove remove AsmVariant. NFC
Summary:
The InlineAsm::AsmDialect is only required for X86; no architecture
makes use of it and as such it gets passed around between arch-specific
and general code while being unused for all architectures but X86.

Since the AsmDialect is queried from a MachineInstr, which we also pass
around, remove the additional AsmDialect parameter and query for it deep
in the X86AsmPrinter only when needed/as late as possible.

This refactor should help later planned refactors to AsmPrinter, as this
difference in the X86AsmPrinter makes it harder to make AsmPrinter more
generic.

Reviewers: craig.topper

Subscribers: jholewinski, arsenm, dschuff, jyknight, dylanmckay, sdardis, nemanjai, jvesely, nhaehnle, javed.absar, sbc100, jgravelle-google, eraman, hiraditya, aheejin, kbarton, fedor.sergeev, asb, rbar, johnrusso, simoncook, apazos, sabuasal, niosHD, jrtc27, zzheng, edward-jones, atanasyan, rogfer01, MartinMosbeck, brucehoult, the_o, PkmX, jocewei, jsji, llvm-commits, peter.smith, srhines

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D60488

llvm-svn: 358101
2019-04-10 16:38:43 +00:00
Lewis Revill aa79a3fe8e [RISCV] Support assembling TLS add and associated modifiers
This patch adds support in the MC layer for parsing and assembling the
4-operand add instruction needed for TLS addressing. This also involves
parsing the %tprel_hi, %tprel_lo and %tprel_add operand modifiers.

Differential Revision: https://reviews.llvm.org/D55341

llvm-svn: 357698
2019-04-04 14:13:37 +00:00
Lewis Revill 24a74096a4 Test commit: Remove double variable assignment
llvm-svn: 357601
2019-04-03 15:54:30 +00:00
Alex Bradbury f8078f6b1d [RISCV] Support assembling @plt symbol operands
This patch allows symbols appended with @plt to parse and assemble with the
R_RISCV_CALL_PLT relocation.

Differential Revision: https://reviews.llvm.org/D55335
Patch by Lewis Revill.

llvm-svn: 357470
2019-04-02 12:47:20 +00:00
Alex Bradbury 44668ae7c7 [RISCV] Attach VK_RISCV_CALL to symbols upon creation
This patch replaces the addition of VK_RISCV_CALL in RISCVMCCodeEmitter by
creating the RISCVMCExpr when tail/call are parsed, or in the codegen case
when the callee symbols are created.

This required adding a new CallSymbol operand to allow only adding
VK_RISCV_CALL to tail/call instructions.

This patch will allow further expansion of parsing and codegen to easily
include PLT symbols which must generate the R_RISCV_CALL_PLT relocation.

Differential Revision: https://reviews.llvm.org/D55560
Patch by Lewis Revill.

llvm-svn: 357396
2019-04-01 14:53:17 +00:00
Alex Bradbury da20f5ca74 [RISCV] Generate address sequences suitable for mcmodel=medium
This patch adds an implementation of a PC-relative addressing sequence to be
used when -mcmodel=medium is specified. With absolute addressing, a 'medium'
codemodel may cause addresses to be out of range. This is because while
'medium' implies a 2 GiB addressing range, this 2 GiB can be at any offset as
opposed to 'small', which implies the first 2 GiB only.

Note that LLVM/Clang currently specifies code models differently to GCC, where
small and medium imply the same functionality as GCC's medlow and medany
respectively.

Differential Revision: https://reviews.llvm.org/D54143
Patch by Lewis Revill.

llvm-svn: 357393
2019-04-01 14:42:56 +00:00
Luis Marques 3091884e25 [RISCV] Add seto pattern expansion
Adds a `seto` pattern expansion. Without it the lowerings of `fcmp one` and 
`fcmp ord` would be inefficient due to an unoptimized double negation.

Differential Revision: https://reviews.llvm.org/D59699

llvm-svn: 357378
2019-04-01 09:54:14 +00:00
Alex Bradbury ca81a56f65 [RISCV] Don't evaluatePCRelLo if a relocation will be forced (e.g. due to linker relaxation)
A pcrel_lo will point to the associated pcrel_hi fixup which in turn points to
the real target. RISCVMCExpr::evaluatePCRelLo will work around this
indirection in order to allow the fixup to be evaluate properly. However, if
relocations are forced (e.g. due to linker relaxation is enabled) then its
evaluation is undesired and will result in a relocation with the wrong target.

This patch modifies evaluatePCRelLo so it will not try to evaluate if the
fixup will be forced as a relocation. A new helper method is added to
RISCVAsmBackend to query this.

Differential Revision: https://reviews.llvm.org/D59686

llvm-svn: 357374
2019-04-01 02:38:27 +00:00
Alex Bradbury 0b2803ee65 [RISCV] Add codegen support for ilp32f, ilp32d, lp64f, and lp64d ("hard float") ABIs
This patch adds support for the RISC-V hard float ABIs, building on top of
rL355771, which added basic target-abi parsing and MC layer support. It also
builds on some re-organisations and expansion of the upstream ABI and calling
convention tests which were recently committed directly upstream.

A number of aspects of the RISC-V float hard float ABIs require frontend
support (e.g. flattening of structs and passing int+fp for fp+fp structs in a
pair of registers), and will be addressed in a Clang patch.

As can be seen from the tests, it would be worthwhile extending
RISCVMergeBaseOffsets to handle constant pool as well as global accesses.

Differential Revision: https://reviews.llvm.org/D59357

llvm-svn: 357352
2019-03-30 17:59:30 +00:00
Alex Bradbury 9681b01c21 [RISCV] Add DAGCombine for (SplitF64 (ConstantFP x))
The SplitF64 node is used on RV32D to convert an f64 directly to a pair of i32
(necessary as bitcasting to i64 isn't legal). When performed on a ConstantFP,
this will result in a FP load from the constant pool followed by a store to
the stack and two integer loads from the stack (necessary as there is no way
to directly move between f64 FPRs and i32 GPRs on RV32D). It's always cheaper
to just materialise integers for the lo and hi parts of the FP constant, so do
that instead.

llvm-svn: 357341
2019-03-30 09:15:47 +00:00
Luis Marques 614fd9d830 [RISCV] Improve codegen for icmp {ne,eq} with a constant
Adds two patterns to improve the codegen of GPR value comparisons with small
constants. Instead of first loading the constant into another register and then
doing an XOR of those registers, these patterns directly use the constant as an
XORI immediate.

llvm-svn: 356990
2019-03-26 12:55:00 +00:00
Alex Bradbury dab1f6fc4e [RISCV] Add basic RV32E definitions and MC layer support
The RISC-V ISA defines RV32E as an alternative "base" instruction set
encoding, that differs from RV32I by having only 16 rather than 32 registers.
This patch adds basic definitions for RV32E as well as MC layer support
(assembling, disassembling) and tests. The only supported ABI on RV32E is
ILP32E.

Add a new RISCVFeatures::validate() helper to RISCVUtils which can be called
from codegen or MC layer libraries to validate the combination of TargetTriple
and FeatureBitSet. Other targets have similar checks (e.g. erroring if SPE is
enabled on PPC64 or oddspreg + o32 ABI on Mips), but they either duplicate the
checks (Mips), or fail to check for both codegen and MC codepaths (PPC).

Codegen for the ILP32E ABI support and RV32E codegen are left for a future
patch/patches.

Differential Revision: https://reviews.llvm.org/D59470

llvm-svn: 356744
2019-03-22 11:21:40 +00:00
Alex Bradbury b9e78c3994 [RISCV] Optimize emission of SELECT sequences
This patch optimizes the emission of a sequence of SELECTs with the same
condition, avoiding the insertion of unnecessary control flow. Such a sequence
often occurs when a SELECT of values wider than XLEN is legalized into two
SELECTs with legal types. We have identified several use cases where the
SELECTs could be interleaved with other instructions. Therefore, we extend the
sequence to include non-SELECT instructions if we are able to detect that the
non-SELECT instructions do not impact the optimization.

This patch supersedes https://reviews.llvm.org/D59096, which attempted to
address this issue by introducing a new SelectionDAG node. Hat tip to Eli
Friedman for his feedback on how to best handle this issue.

Differential Revision: https://reviews.llvm.org/D59355
Patch by Luís Marques.

llvm-svn: 356741
2019-03-22 10:45:03 +00:00
Alex Bradbury 3369101158 [RISCV] Allow conversion of CC logic to bitwise logic
Indicates in the TargetLowering interface that conversions from CC logic to
bitwise logic are allowed. Adds tests that show the benefit when optimization
opportunities are detected. Also adds tests that show that when the optimization
is not applied correct code is generated (but opportunities for other
optimizations remain).

Differential Revision: https://reviews.llvm.org/D59596
Patch by Luís Marques.

llvm-svn: 356740
2019-03-22 10:39:22 +00:00
Alex Bradbury 997947961a [RISCV][NFC] Factor out matchRegisterNameHelper in RISCVAsmParser.cpp
Contains common logic to match a string to a register name.

llvm-svn: 356330
2019-03-17 12:02:32 +00:00
Alex Bradbury b18e314a7c [RISCV] Fix RISCVAsmParser::ParseRegister and add tests
RISCVAsmParser::ParseRegister is called from AsmParser::parseRegisterOrNumber,
which in turn is called when processing CFI directives. The RISC-V
implementation wasn't setting RegNo, and so was incorrect. This patch address
that and adds cfi directive tests that demonstrate the fix. A follow-up patch
will factor out the register parsing logic shared between ParseRegister and
parseRegister.

llvm-svn: 356329
2019-03-17 12:00:58 +00:00
Alex Bradbury fec503acb6 [RISCV] Fix rL356123
The wrong version of the patch was committed. This fixes typos that broke the build.

llvm-svn: 356124
2019-03-14 08:31:35 +00:00
Alex Bradbury 8dbc6398e1 [RISCV][NFC] Rename callee saved regs 'CSR' to CSR_ILP32_LP64 and minor RISCVRegisterInfo refactoring
The CSR renaming further prepares the way for an upcoming patch adding support for more
RISC-V ABIs.

Modify RISCVRegisterInfo::getCalleeSavedRegs and
RISCVRegisterInfo::getReservedRegs to do MF->getSubtarget<RISCVSubtarget>()
once rather than multiple times.

llvm-svn: 356123
2019-03-14 08:28:48 +00:00
Alex Bradbury 8a70468a27 [RISCV] Only mark fp as reserved if the function has a dedicated frame pointer
This follows similar logic in the ARM and Mips backends, and allows the free
use of s0 in functions without a dedicated frame pointer. The changes in
callee-saved-gprs.ll most clearly show the effect of this patch.

llvm-svn: 356063
2019-03-13 16:33:45 +00:00
Alex Bradbury 18f95e6a6f [RISCV] Replace incorrect use of sizeof with array_lengthof
RISCVDisassembler was incorrectly using sizeof(Arr) when it should have used
sizeof(Arr)/sizeof(Arr[0]). Update to use array_lengthof instead.

llvm-svn: 356035
2019-03-13 09:22:57 +00:00
Eli Friedman 74b6aae4e8 [RISCV][MC] Find matching pcrel_hi fixup in more cases.
If a symbol points to the end of a fragment, instead of searching for
fixups in that fragment, search in the next fragment.

Fixes spurious assembler error with subtarget change next to "la"
pseudo-instruction, or expanded equivalent.

Alternate proposal to fix the problem discussed in
https://reviews.llvm.org/D58759.

Testcase by Ana Pazos.

Differential Revision: https://reviews.llvm.org/D58943

llvm-svn: 355946
2019-03-12 18:14:16 +00:00
Alex Bradbury 4d20cc21c7 [RISCV] Do a sign-extension in a compare-and-swap of 32 bit in RV64A
AtomicCmpSwapWithSuccess is legalised into an AtomicCmpSwap plus a comparison.
This requires an extension of the value which, by default, is a
zero-extension. When we later lower AtomicCmpSwap into a PseudoCmpXchg32 and then expanded in
RISCVExpandPseudoInsts.cpp, the lr.w instruction does a sign-extension.

This mismatch of extensions causes the comparison to fail when the compared
value is negative. This change overrides TargetLowering::getExtendForAtomicOps
for RISC-V so it does a sign-extension instead.

Differential Revision: https://reviews.llvm.org/D58829
Patch by Ferran Pallarès Roca.

llvm-svn: 355869
2019-03-11 21:41:22 +00:00
Alex Bradbury b6d322bdc2 [RISCV] Allow fp as an alias of s0
The RISC-V Assembly Programmer's Manual defines fp as another alias of x8.
However, our tablegen rules only recognise s0. This patch adds fp as another
alias of x8. GCC also accepts fp.

Differential Revision: https://reviews.llvm.org/D59209
Patch by Ferran Pallarès Roca.

llvm-svn: 355867
2019-03-11 21:35:26 +00:00
Alex Bradbury 2c6c84e52c [RISCV][NFC] Convert some MachineBaiscBlock::iterator(MI) to MI.getIterator()
llvm-svn: 355864
2019-03-11 20:43:29 +00:00
Alex Bradbury 62c8a57a74 [RISCV][NFC] Minor refactoring of CC_RISCV
Immediately check if we need to early-exit as we have a return value that
can't be returned directly. Also tweak following if/else.

llvm-svn: 355773
2019-03-09 11:16:27 +00:00
Alex Bradbury bd0eff316a [RISCV][NFC] Split out emitSelectPseudo from EmitInstrWithCustomInserter
It's cleaner and more consistent to have a separate helper function here.

llvm-svn: 355772
2019-03-09 09:30:14 +00:00
Alex Bradbury fea4957177 [RISCV] Support -target-abi at the MC layer and for codegen
This patch adds proper handling of -target-abi, as accepted by llvm-mc and
llc. Lowering (codegen) for the hard-float ABIs will follow in a subsequent
patch. However, this patch does add MC layer support for the hard float and
RVE ABIs (emission of the appropriate ELF flags
https://github.com/riscv/riscv-elf-psabi-doc/blob/master/riscv-elf.md#-file-header).

ABI parsing must be shared between codegen and the MC layer, so we add
computeTargetABI to RISCVUtils. A warning will be printed if an invalid or
unrecognized ABI is given.

Differential Revision: https://reviews.llvm.org/D59023

llvm-svn: 355771
2019-03-09 09:28:06 +00:00
Ana Pazos 5254d1baae [RISCV] Allow access to FP CSRs without F extension
Summary:
Floating-point CSRs should be accessible even when F extension is not enabled.
But pseudo instructions that access floating point CSRs still require the F extension.
GNU tools already implement this behavior. RISC-V spec is pending update to reflect
this behavior and to extend it to pseudo instructions that access floating point CSRs.

Reviewers: asb

Reviewed By: asb

Subscribers: asb, rbar, johnrusso, simoncook, sabuasal, niosHD, kito-cheng, shiva0217, zzheng, edward-jones, rogfer01, MartinMosbeck, brucehoult, the_o, rkruppe, PkmX, jocewei, llvm-commits

Differential Revision: https://reviews.llvm.org/D58932

llvm-svn: 355753
2019-03-08 23:01:08 +00:00
Alex Bradbury db67be889d [RISCV][NFC] IsEligibleForTailCallOptimization -> isEligibleForTailCallOptimization
Also clang-format the modified hunks.

llvm-svn: 354584
2019-02-21 14:31:41 +00:00
Alex Bradbury 047170cfc3 [RISCV] Add implied zero offset load/store alias patterns
Allow load/store instructions with implied zero offset for compatibility with
GNU assembler.

Differential Revision: https://reviews.llvm.org/D57141
Patch by James Clarke.

llvm-svn: 354581
2019-02-21 14:09:34 +00:00
Kito Cheng 303217e8b4 [RISCV] Implement pseudo instructions for load/store from a symbol address.
Summary:
Those pseudo-instructions are making load/store instructions able to
load/store from/to a symbol, and its always using PC-relative addressing
to generating a symbol address.

Reviewers: asb, apazos, rogfer01, jrtc27

Differential Revision: https://reviews.llvm.org/D50496

llvm-svn: 354430
2019-02-20 03:31:32 +00:00
Alex Bradbury 6aae216109 [RISCV][NFC] Move some std::string to StringRef
llvm-svn: 354333
2019-02-19 14:42:00 +00:00
Alex Bradbury 22531c4a14 [RISCV] Add assembler support for LA pseudo-instruction
This patch also introduces the emitAuipcInstPair helper, which is then used
for both emitLoadAddress and emitLoadLocalAddress.

Differential Revision: https://reviews.llvm.org/D55325
Patch by James Clarke.

llvm-svn: 354111
2019-02-15 09:53:32 +00:00
Alex Bradbury 8eb87e59a6 [RISCV] Support assembling %got_pcrel_hi operator
Differential Revision: https://reviews.llvm.org/D55279
Patch by James Clarke.

llvm-svn: 354110
2019-02-15 09:43:46 +00:00
Craig Topper 784929d045 Implementation of asm-goto support in LLVM
This patch accompanies the RFC posted here:
http://lists.llvm.org/pipermail/llvm-dev/2018-October/127239.html

This patch adds a new CallBr IR instruction to support asm-goto
inline assembly like gcc as used by the linux kernel. This
instruction is both a call instruction and a terminator
instruction with multiple successors. Only inline assembly
usage is supported today.

This also adds a new INLINEASM_BR opcode to SelectionDAG and
MachineIR to represent an INLINEASM block that is also
considered a terminator instruction.

There will likely be more bug fixes and optimizations to follow
this, but we felt it had reached a point where we would like to
switch to an incremental development model.

Patch by Craig Topper, Alexander Ivchenko, Mikhail Dvoretckii

Differential Revision: https://reviews.llvm.org/D53765

llvm-svn: 353563
2019-02-08 20:48:56 +00:00
Alex Bradbury 7539fa2c2d [RISCV] Implement RV64D codegen
This patch:
* Adds necessary RV64D codegen patterns
* Modifies CC_RISCV so it will properly handle f64 types (with soft float ABI)

Note that in general there is no reason to try to select fcvt.w[u].d rather than fcvt.l[u].d for i32 conversions because fptosi/fptoui produce poison if the input won't fit into the target type.

Differential Revision: https://reviews.llvm.org/D53237

llvm-svn: 352833
2019-02-01 03:53:30 +00:00
Alex Bradbury d834d8301d [RISCV] Add RV64F codegen support
This requires a little extra work due tothe fact i32 is not a legal type. When
call lowering happens post-legalisation (e.g. when an intrinsic was inserted
during legalisation). A bitcast from f32 to i32 can't be introduced. This is
similar to the challenges with RV32D. To handle this, we introduce
target-specific DAG nodes that perform bitcast+anyext for f32->i64 and
trunc+bitcast for i64->f32.

Differential Revision: https://reviews.llvm.org/D53235

llvm-svn: 352807
2019-01-31 22:48:38 +00:00
Shiva Chen 5af037f1e9 [RISCV] Insert R_RISCV_ALIGN relocation type and Nops for code alignment when linker relaxation enabled
Linker relaxation may change code size. We need to fix up the alignment
of alignment directive in text section by inserting Nops and R_RISCV_ALIGN
relocation type. So then linker could satisfy the alignment by removing Nops.

To do this:

1. Add shouldInsertExtraNopBytesForCodeAlign target hook to calculate
   the Nops we need to insert.

2. Add shouldInsertFixupForCodeAlign target hook to insert
   R_RISCV_ALIGN fixup type.

Differential Revision: https://reviews.llvm.org/D47755

llvm-svn: 352616
2019-01-30 11:16:59 +00:00
Alex Bradbury 0092df0669 [RISCV] Add target DAG combine for bitcast fabs/fneg on RV32FD
DAGCombiner::visitBITCAST will perform:
 fold (bitconvert (fneg x)) -> (xor (bitconvert x), signbit)
 fold (bitconvert (fabs x)) -> (and (bitconvert x), (not signbit))

As shown in double-bitmanip-dagcombines.ll, this can be advantageous. But
RV32FD doesn't use bitcast directly (as i64 isn't a legal type), and instead
uses RISCVISD::SplitF64. This patch adds an equivalent DAG combine for
SplitF64.

llvm-svn: 352247
2019-01-25 21:55:48 +00:00
Ana Pazos 05a6064385 Reapply: [RISCV] Set isAsCheapAsAMove for ADDI, ORI, XORI, LUI
This reapplies commit r352010 with RISC-V test fixes.

llvm-svn: 352237
2019-01-25 20:22:49 +00:00
Alex Bradbury 456d3798d6 [RISCV] Custom-legalise i32 SDIV/UDIV/UREM on RV64M
Follow the same custom legalisation strategy as used in D57085 for
variable-length shifts (see that patch summary for more discussion). Although
we may lose out on some late-stage DAG combines, I think this custom
legalisation strategy is ultimately easier to reason about.

There are some codegen changes in rv64m-exhaustive-w-insts.ll but they are all
neutral in terms of the number of instructions.

Differential Revision: https://reviews.llvm.org/D57096

llvm-svn: 352171
2019-01-25 05:11:34 +00:00
Alex Bradbury 299d690a50 [RISCV] Custom-legalise 32-bit variable shifts on RV64
The previous DAG combiner-based approach had an issue with infinite loops
between the target-dependent and target-independent combiner logic (see
PR40333). Although this was worked around in rL351806, the combiner-based
approach is still potentially brittle and can fail to select the 32-bit shift
variant when profitable to do so, as demonstrated in the pr40333.ll test case.

This patch instead introduces target-specific SelectionDAG nodes for
SHLW/SRLW/SRAW and custom-lowers variable i32 shifts to them. pr40333.ll is a
good example of how this approach can improve codegen.

This adds DAG combine that does SimplifyDemandedBits on the operands (only
lower 32-bits of first operand and lower 5 bits of second operand are read).
This seems better than implementing SimplifyDemandedBitsForTargetNode as there
is no guarantee that would be called (and it's not for e.g. the anyext return
test cases). Also implements ComputeNumSignBitsForTargetNode.

There are codegen changes in atomic-rmw.ll and atomic-cmpxchg.ll but the new
instruction sequences are semantically equivalent.

Differential Revision: https://reviews.llvm.org/D57085

llvm-svn: 352169
2019-01-25 05:04:00 +00:00
Ana Pazos 5c0521ac52 Revert "[RISCV] Set isAsCheapAsAMove for ADDI, ORI, XORI, LUI"
This reverts commit ccfb060ecb5d7e18ea729455660484d576bde2cc.

Some tests need to to fixed before reapplying this commit.

llvm-svn: 352014
2019-01-24 03:00:26 +00:00
Ana Pazos c54abc520c [RISCV] Set isAsCheapAsAMove for ADDI, ORI, XORI, LUI
Summary:
Affected instructions:
PseudoLI simplest form (ADDI with X0)
ALU operations with immediate (they do not set status flag - ADDI, ORI, XORI)

Reviewers: asb

Reviewed By: asb

Subscribers: shiva0217, rkruppe, kito-cheng, asb, rbar, johnrusso, simoncook, sabuasal, niosHD, zzheng, edward-jones, mgrang, rogfer01, MartinMosbeck, brucehoult, the_o, PkmX, jocewei

Differential Revision: https://reviews.llvm.org/D56526

llvm-svn: 352010
2019-01-24 02:41:40 +00:00
Ana Pazos 29ace0e62c [RISCV] Set isReMaterializable for ORI, XORI
Reviewers: asb

Reviewed By: asb

Subscribers: asb, rbar, johnrusso, simoncook, sabuasal, niosHD, kito-cheng, shiva0217, zzheng, edward-jones, rogfer01, MartinMosbeck, brucehoult, the_o, rkruppe, PkmX, jocewei

Differential Revision: https://reviews.llvm.org/D57069

llvm-svn: 352008
2019-01-24 02:31:23 +00:00
Ana Pazos 5f51e09c7b Fixed isReMaterializable setting for LUI instruction.
llvm-svn: 351895
2019-01-22 22:59:47 +00:00
Matt Arsenault 39508331ef Reapply "IR: Add fp operations to atomicrmw"
This reapplies commits r351778 and r351782 with
RISCV test fixes.

llvm-svn: 351850
2019-01-22 18:18:02 +00:00
Alex Bradbury 0a9c9a8daa [RISCV][NFC] Change naming scheme for RISC-V specific DAG nodes
Previously we had names like 'Call' or 'Tail'. This potentially clashes with
the naming scheme used elsewhere in RISCVInstrInfo.td. Many other backends
would use names like AArch64call or PPCtail. I prefer the SystemZ approach,
which uses prefixed all-lowercase names. This matches the naming scheme used
for target-independent SelectionDAG nodes.

llvm-svn: 351823
2019-01-22 14:05:11 +00:00
Alex Bradbury cd26560e46 [RISCV] Quick fix for PR40333
Avoid the infinite loop caused by the target DAG combine converting ANYEXT to
SIGNEXT and the target-independent DAG combine logic converting back to
ANYEXT. Do this by not adding the new node to the worklist.

Committing directly as this definitely doesn't make the problem any worse, and
I intend to follow-up with a patch that avoids this custom combiner logic
altogether and just lowers the i32 operations to a target-specific
SelectionDAG node. This should be easier to reason about and improve codegen
quality in some cases (though may miss out on some later DAG combines).

llvm-svn: 351806
2019-01-22 12:11:53 +00:00
Chandler Carruth 285fe716c5 Revert r351778: IR: Add fp operations to atomicrmw
This broke the RISCV build, and even with that fixed, one of the RISCV
tests behaves surprisingly differently with asserts than without,
leaving there no clear test pattern to use. Generally it seems bad for
hte IR to differ substantially due to asserts (as in, an alloca is used
with asserts that isn't needed without!) and nothing I did simply would
fix it so I'm reverting back to green.

This also required reverting the RISCV build fix in r351782.

llvm-svn: 351796
2019-01-22 10:29:58 +00:00
Alex Bradbury 1b9cd446f7 [RISCV][NFC] Add break to case statement in RISCVDAGToDAGISel::Select
The break isn't strictly needed yet as there is no subsequent entry in the
case. But adding to prevent mistakes further down the road.

llvm-svn: 351785
2019-01-22 07:22:00 +00:00
Alex Bradbury b96b755c4d [RISCV] Fix build after r351778
Also add a comment to explain the expansion strategy for atomicrmw
{fadd,fsub}.

llvm-svn: 351782
2019-01-22 05:06:57 +00:00
Matt Arsenault bfdba5e4fc IR: Add fp operations to atomicrmw
Add just fadd/fsub for now.

llvm-svn: 351778
2019-01-22 03:32:36 +00:00
Kito Cheng 5e8798f987 [RISCV] Add R_RISCV_RELAX relocation to all possible relax candidates.
Summary:
Add R_RISCV_RELAX relocation to all possible relax candidates and
update corresponding testcase.

Reviewers: asb, apazos

Differential Revision: https://reviews.llvm.org/D46677

llvm-svn: 351723
2019-01-21 05:27:09 +00:00
Chandler Carruth 2946cd7010 Update the file headers across all of the LLVM projects in the monorepo
to reflect the new license.

We understand that people may be surprised that we're moving the header
entirely to discuss the new license. We checked this carefully with the
Foundation's lawyer and we believe this is the correct approach.

Essentially, all code in the project is now made available by the LLVM
project under our new license, so you will see that the license headers
include that license only. Some of our contributors have contributed
code under our old license, and accordingly, we have retained a copy of
our old license notice in the top-level files in each project and
repository.

llvm-svn: 351636
2019-01-19 08:50:56 +00:00
Alex Bradbury 07f1c62371 [RISCV] Add codegen support for RV64A
In order to support codegen RV64A, this patch:
* Introduces masked atomics intrinsics for atomicrmw operations and cmpxchg
  that use the i64 type. These are ultimately lowered to masked operations
  using lr.w/sc.w, but we need to use these alternate intrinsics for RV64
  because i32 is not legal
* Modifies RISCVExpandPseudoInsts.cpp to handle PseudoAtomicLoadNand64 and
  PseudoCmpXchg64
* Modifies the AtomicExpandPass hooks in RISCVTargetLowering to sext/trunc as
  needed for RV64 and to select the i64 intrinsic IDs when necessary
* Adds appropriate patterns to RISCVInstrInfoA.td
* Updates test/CodeGen/RISCV/atomic-*.ll to show RV64A support

This ends up being a fairly mechanical change, as the logic for RV32A is
effectively reused.

Differential Revision: https://reviews.llvm.org/D53233

llvm-svn: 351422
2019-01-17 10:04:39 +00:00
Alex Bradbury 61aa940074 [RISCV] Introduce codegen patterns for RV64M-only instructions
As discussed on llvm-dev
<http://lists.llvm.org/pipermail/llvm-dev/2018-December/128497.html>, we have
to be careful when trying to select the *w RV64M instructions. i32 is not a
legal type for RV64 in the RISC-V backend, so operations have been promoted by
the time they reach instruction selection. Information about whether the
operation was originally a 32-bit operations has been lost, and it's easy to
write incorrect patterns.

Similarly to the variable 32-bit shifts, a DAG combine on ANY_EXTEND will
produce a SIGN_EXTEND if this is likely to result in sdiv/udiv/urem being
selected (and so save instructions to sext/zext the input operands).

Differential Revision: https://reviews.llvm.org/D53230

llvm-svn: 350993
2019-01-12 07:43:06 +00:00
Alex Bradbury d05eae7a7b [RISCV] Add patterns for RV64I SLLW/SRLW/SRAW instructions
This restores support for selecting the SLLW/SRLW/SRAW instructions, which was
removed in rL348067 as the previous patterns made some unsafe assumptions.
Also see the related llvm-dev discussion
<http://lists.llvm.org/pipermail/llvm-dev/2018-December/128497.html>

Ultimately I didn't introduce a custom SelectionDAG node, but instead added a
DAG combine that inserts an AssertZext i5 on the shift amount for an i32
variable-length shift and also added an ANY_EXTEND DAG-combine which will
instead produce a SIGN_EXTEND for an i32 variable-length shift, increasing the
opportunity to safely select SLLW/SRLW/SRAW.

There are obviously different ways of addressing this (a number discussed in
the llvm-dev thread), so I'd welcome further feedback and comments.

Note that there are now some cases in
test/CodeGen/RISCV/rv64i-exhaustive-w-insts.ll where sraw/srlw/sllw is
selected even though sra/srl/sll could be used without any extra instructions.
Given both are semantically equivalent, there doesn't seem a good reason to
prefer one vs the other. Given that would require more logic to still select
sra/srl/sll in those cases, I've left it preferring the *w variants.

Differential Revision: https://reviews.llvm.org/D56264

llvm-svn: 350992
2019-01-12 07:32:31 +00:00
Alex Bradbury 6f302b8a69 [RISCV][MC] Add support for evaluating constant symbols as immediates
This further improves compatibility with GNU as, allowing input such as the
following to be assembled:

.equ CONST, 0x123456
li a0, CONST
addi a0, a0, %lo(CONST)

.equ CONST, 1
slli a0, a0, CONST

Note that we don't have perfect compatibility with gas, as it will avoid
emitting a relocation in this case:

addi a0, a0, %lo(CONST2)
.equ CONST2, 0x123456

Thanks to Shiva Chen for suggesting a better way to approach this during review.

Differential Revision: https://reviews.llvm.org/D52298

llvm-svn: 350831
2019-01-10 15:33:17 +00:00
Alex Bradbury 2ba76be882 [RISCV][MC] Accept %lo and %pcrel_lo on operands to li
This matches GNU assembler behaviour.

llvm-svn: 350321
2019-01-03 14:41:41 +00:00
Alex Bradbury eb3a64a4da [RISCV] Properly evaluate fixup_riscv_pcrel_lo12
This is a update to D43157 to correctly handle fixup_riscv_pcrel_lo12.

Notable changes:

Rebased onto trunk
Handle and test S-type
Test case pcrel-hilo.s is merged into relocations.s

D43157 description:
VK_RISCV_PCREL_LO has to be handled specially. The MCExpr inside is
actually the location of an auipc instruction with a VK_RISCV_PCREL_HI fixup
pointing to the real target.

Differential Revision: https://reviews.llvm.org/D54029
Patch by Chih-Mao Chen and Michael Spencer.

llvm-svn: 349764
2018-12-20 14:52:15 +00:00
Alex Bradbury 919f5fb8ca [RISCV] Add support for the various RISC-V FMA instruction variants
Adds support for the various RISC-V FMA instructions (fmadd, fmsub, fnmsub, fnmadd).

The criteria for choosing whether a fused add or subtract is used, as well as
whether the product is negated or not, is whether some of the arguments to the
llvm.fma.* intrinsic are negated or not. In the tests, extraneous fadd
instructions were added to avoid the negation being performed using a xor
trick, which prevented the proper FMA forms from being selected and thus
tested.

The FMA instruction patterns might seem incorrect (e.g., fnmadd: -rs1 * rs2 -
rs3), but they should be correct. The misleading names were inherited from
MIPS, where the negation happens after computing the sum.

The llvm.fmuladd.* intrinsics still do not generate RISC-V FMA instructions,
as that depends on TargetLowering::isFMAFasterthanFMulAndFAdd.

Some comments in the test files about what type of instructions are there
tested were updated, to better reflect the current content of those test
files.

Differential Revision: https://reviews.llvm.org/D54205
Patch by Luís Marques.

llvm-svn: 349023
2018-12-13 10:49:05 +00:00
David Green ca29c271d2 [Targets] Add errors for tiny and kernel codemodel on targets that don't support them
Adds fatal errors for any target that does not support the Tiny or Kernel
codemodels by rejigging the getEffectiveCodeModel calls.

Differential Revision: https://reviews.llvm.org/D50141

llvm-svn: 348585
2018-12-07 12:10:23 +00:00
Alex Bradbury 757d296222 [RISCV] Remove RV64I SLLW/SRLW/SRAW patterns and add new test cases
As noted by Eli Friedman <https://reviews.llvm.org/D52977?id=168629#1315291>, 
the RV64I shift patterns for SLLW/SRLW/SRAW make some incorrect assumptions. 
SRAW assumed that (sext_inreg foo, i32) could only be produced when 
sign-extended an i32. However, it can be produced by input such as:

define i64 @tricky_ashr(i64 %a, i64 %b) {
  %1 = shl i64 %a, 32
  %2 = ashr i64 %1, 32
  %3 = ashr i64 %2, %b
  ret i64 %3
}

It's important not to select sraw in the above case, because sraw only uses 
bits lower 5 bits from the shift, while a shift of 32-63 would be valid.

Similarly, the patterns for srlw assumed (and foo, 0xffffffff) would only be 
produced when zero-extending a value that was originally i32 in LLVM IR. This
is obviously incorrect.

This patch removes the SLLW/SRLW/SRAW shift patterns for the time being and 
adds test cases that would demonstrate a miscompile if the incorrect patterns 
were re-added.

llvm-svn: 348067
2018-12-01 05:00:00 +00:00
Alex Bradbury 4830fdd21a [RISCV] Add additional CSR instruction aliases (imm. operands)
This patch adds CSR instructions aliases for the cases where the instruction 
takes an immediate operand but the alias doesn't have the i suffix. This is 
necessary for gas/gcc compatibility.

gas doesn't do a similar conversion for fsflags or fsrm, so this should be 
complete.

Differential Revision: https://reviews.llvm.org/D55008
Patch by Luís Marques.

llvm-svn: 347991
2018-11-30 14:10:52 +00:00
Alex Bradbury 26403def69 [RISCV] Add UNIMP instruction (32- and 16-bit forms)
This patch adds support for UNIMP in both 32- and 16-bit forms. The 32-bit 
form can be seen as a variant of the ECALL/EBREAK/etc. family of instructions. 
The 16-bit form is just all zeroes, which isn't a valid RISC-V instruction, 
but still follows the 16-bit instruction form (i.e. bits 0-1 != 11).

Until recently unimp was undocumented and supported just by binutils, which 
printed unimp for either the 16 or 32-bit form. Both forms are now documented 
<https://github.com/riscv/riscv-asm-manual/pull/20> and binutils now supports 
c.unimp <https://sourceware.org/ml/binutils-cvs/2018-11/msg00179.html>.

Differential Revision: https://reviews.llvm.org/D54316
Patch by Luís Marques.

llvm-svn: 347988
2018-11-30 13:39:17 +00:00
Alex Bradbury e0e62e97df [TargetLowering][RISCV] Introduce isSExtCheaperThanZExt hook and implement for RISC-V
DAGTypeLegalizer::PromoteSetCCOperands currently prefers to zero-extend 
operands when it is able to do so. For some targets this is more expensive 
than a sign-extension, which is also a valid choice. Introduce the 
isSExtCheaperThanZExt hook and use it in the new SExtOrZExtPromotedInteger 
helper. On RISC-V, we prefer sign-extension for FromTy == MVT::i32 and ToTy == 
MVT::i64, as it can be performed using a single instruction.

Differential Revision: https://reviews.llvm.org/D52978

llvm-svn: 347977
2018-11-30 09:56:54 +00:00
Alex Bradbury bc96a98ed0 [RISCV] Introduce codegen patterns for instructions introduced in RV64I
As discussed in the RFC 
<http://lists.llvm.org/pipermail/llvm-dev/2018-October/126690.html>, 64-bit 
RISC-V has i64 as the only legal integer type.  This patch introduces patterns 
to support codegen of the new instructions 
introduced in RV64I: addiw, addiw, subw, sllw, slliw, srlw, srliw, sraw, 
sraiw, ld, sd.

Custom selection code is needed for srliw as SimplifyDemandedBits will remove 
lower bits from the mask, meaning the obvious pattern won't work:

def : Pat<(sext_inreg (srl (and GPR:$rs1, 0xffffffff), uimm5:$shamt), i32),
          (SRLIW GPR:$rs1, uimm5:$shamt)>;
This is sufficient to compile and execute all of the GCC torture suite for 
RV64I other than those files using frameaddr or returnaddr intrinsics 
(LegalizeDAG doesn't know how to promote the operands - a future patch 
addresses this).

When promoting i32 sltu/sltiu operands, it would be more efficient to use 
sign-extension rather than zero-extension for RV64. A future patch adds a hook 
to allow this.

Differential Revision: https://reviews.llvm.org/D52977

llvm-svn: 347973
2018-11-30 09:38:44 +00:00
Alex Bradbury 66d9a752b9 [RISCV] Implement codegen for cmpxchg on RV32IA
Utilise a similar ('late') lowering strategy to D47882. The changes to 
AtomicExpandPass allow this strategy to be utilised by other targets which 
implement shouldExpandAtomicCmpXchgInIR.

All cmpxchg are lowered as 'strong' currently and failure ordering is ignored. 
This is conservative but correct.

Differential Revision: https://reviews.llvm.org/D48131

llvm-svn: 347914
2018-11-29 20:43:42 +00:00
Alex Bradbury 893e5bc774 [RISCV] Support .option push and .option pop
This adds support in the RISCVAsmParser the storing of Subtarget feature bits to a stack so that they can be pushed/popped to enable/disable multiple features at once.

Differential Revision: https://reviews.llvm.org/D46424
Patch by Lewis Revill.

llvm-svn: 347774
2018-11-28 16:39:14 +00:00
Alex Bradbury b4a64cede8 [RISCV][NFC] Define and use the new CA instruction format
The RISC-V ISA manual was updated on 2018-11-07 (commit 00557c3) to define a 
new compressed instruction format, RVC format CA (no actual instruction 
encodings were changed). This patch updates the RISC-V backend to define the 
new format, and to use it in the relevant instructions.

Differential Revision: https://reviews.llvm.org/D54302
Patch by Luís Marques.

llvm-svn: 347043
2018-11-16 10:33:23 +00:00
Alex Bradbury 2146e8fb1e [RISCV] Constant materialisation for RV64I
This commit introduces support for materialising 64-bit constants for RV64I,
making use of the RISCVMatInt::generateInstSeq helper in order to share logic
for immediate materialisation with the MC layer (where it's used for the li
pseudoinstruction).

test/CodeGen/RISCV/imm.ll is updated to test RV64, and gains new 64-bit
constant tests. It would be preferable if anyext constant returns were sign
rather than zero extended (see PR39092). This patch simply adds an explicit
signext to the returns in imm.ll.

Further optimisations for constant materialisation are possible, most notably
for mask-like values which can be generated my loading -1 and shifting right.
A future patch will standardise on the C++ codepath for immediate selection on
RV32 as well as RV64, and then add further such optimisations to
RISCVMatInt::generateInstSeq in order to benefit both RV32 and RV64 for
codegen and li expansion.

Differential Revision: https://reviews.llvm.org/D52962

llvm-svn: 347042
2018-11-16 10:14:16 +00:00
Alex Bradbury f809d89980 [RISCV] Mark C.EBREAK instruction as having side effects
C.EBREAK was defined with hasSideEffects = 0, which is incorrect and 
inconsistent with the non-compressed instruction form. This patch corrects 
this oversight.

This wouldn't cause codegen issues, as compressed instructions are only ever 
generated by converting the non-compressed form as an MCInst. But having 
correct flags is still worthwhile.

Differential Revision: https://reviews.llvm.org/D54256
Patch by Luís Marques.

llvm-svn: 346959
2018-11-15 14:52:24 +00:00
Alex Bradbury 7727240438 [RISCV] Mark FREM as Expand
Mark the FREM SelectionDAG node as Expand, which is necessary in order to 
support the frem IR instruction on RISC-V. This is expanded into a library 
call. Adds the corresponding test. Previously, this would have triggered an 
assertion at instruction selection time.

Differential Revision: https://reviews.llvm.org/D54159
Patch by Luís Marques.

llvm-svn: 346958
2018-11-15 14:46:11 +00:00
Alex Bradbury 22c091fc3c [RISCV] Introduce the RISCVMatInt::generateInstSeq helper
Logic to load 32-bit and 64-bit immediates is currently present in
RISCVAsmParser::emitLoadImm in order to support the li pseudoinstruction. With
the introduction of RV64 codegen, there is a greater benefit of sharing
immediate materialisation logic between the MC layer and codegen. The
generateInstSeq helper allows this by producing a vector of simple structs
representing the chosen instructions. This can then be consumed in the MC
layer to produce MCInsts or at instruction selection time to produce
appropriate SelectionDAG node. Sharing this logic means that both the li
pseudoinstruction and codegen can benefit from future optimisations, and
that this logic can be used for materialising constants during RV64 codegen.

This patch does contain a behaviour change: addi will now be produced on RV64
when no lui is necessary to materialise the constant. In that case addiw takes
x0 as the source register, so is semantically identical to addi.

Differential Revision: https://reviews.llvm.org/D52961

llvm-svn: 346937
2018-11-15 10:11:31 +00:00
Alex Bradbury 9c03e4cacd [RISCV] Support .option relax and .option norelax
This extends the .option support from D45864 to enable/disable the relax 
feature flag from D44886

During parsing of the relax/norelax directives, the RISCV::FeatureRelax 
feature bits of the SubtargetInfo stored in the AsmParser are updated 
appropriately to reflect whether relaxation is currently enabled in the 
parser. When an instruction is parsed, the parser checks if relaxation is 
currently enabled and if so, gets a handle to the AsmBackend and sets the 
ForceRelocs flag. The AsmBackend uses a combination of the original 
RISCV::FeatureRelax feature bits set by e.g -mattr=+/-relax and the 
ForceRelocs flag to determine whether to emit relocations for symbol and 
branch diffs. Diff relocations should therefore only not be emitted if the 
relax flag was not set on the command line and no instruction was ever parsed 
in a section with relaxation enabled to ensure correct diffs are emitted.

Differential Revision: https://reviews.llvm.org/D46423
Patch by Lewis Revill.

llvm-svn: 346655
2018-11-12 14:25:07 +00:00
Alex Bradbury 1cc2d0b9fb [RISCV] Avoid unnecessary XOR for seteq/setne 0
Differential Revision: https://reviews.llvm.org/D53492

Patch by James Clarke.

llvm-svn: 346497
2018-11-09 14:47:36 +00:00
Alex Bradbury 52c27785ce [RISCV] Add some missing expansions for floating-point intrinsics
A number of intrinsics, such as llvm.sin.f32, would result in a failure to 
select. This patch adds expansions for the relevant selection DAG nodes, as 
well as exhaustive testing for all f32 and f64 intrinsics.

The codegen for FMA remains a TODO item, pending support for the various 
RISC-V FMA instruction variants.

The llvm.minimum.f32.* and llvm.maximum.* tests are commented-out, pending 
upstream support for target-independent expansion, as discussed in 
http://lists.llvm.org/pipermail/llvm-dev/2018-November/127408.html.

Differential Revision: https://reviews.llvm.org/D54034
Patch by Luís Marques.

llvm-svn: 346034
2018-11-02 19:50:38 +00:00
Alex Bradbury 74d4931da2 [RISCV] Use PatFrags for variable shift patterns
This follows SystemZ and I think is cleaner vs the multiclass.

llvm-svn: 345262
2018-10-25 12:45:20 +00:00
Alex Bradbury 748d080e62 [RISCV] Eliminate unnecessary masking of promoted shift amounts
SelectionDAGBuilder::visitShift will always zero-extend a shift amount when it
is promoted to the ShiftAmountTy. This results in zero-extension (masking)
which is unnecessary for RISC-V as the shift operations only read the lower 5
or 6 bits (RV32 or RV64).

I initially proposed adding a getExtendForShiftAmount hook so the shift amount
can be any-extended (D52975). @efriedma explained this was unsafe, so I have
instead eliminate the unnecessary and operations at instruction selection time
in a manner similar to X86InstrCompiler.td.

Differential Revision: https://reviews.llvm.org/D53224

llvm-svn: 344432
2018-10-12 23:18:52 +00:00
Ana Pazos 0a5fcefa31 [RISCV] Fix disassembling of fence instruction with invalid field
Summary:
Instruction with 0 in fence field being disassembled as fence , iorw.
Printing "unknown" to match GAS behavior.

This bug was uncovered by a LLVM MC Disassembler Protocol Buffer Fuzzer
for the RISC-V assembly language.

Reviewers: asb

Subscribers: rbar, johnrusso, simoncook, sabuasal, niosHD, kito-cheng, shiva0217, zzheng, edward-jones, mgrang, rogfer01, MartinMosbeck, brucehoult, the_o, rkruppe, jfb, PkmX, jocewei, asb

Differential Revision: https://reviews.llvm.org/D51828

llvm-svn: 344309
2018-10-11 22:49:13 +00:00
Alex Bradbury 639df9e4c0 [RISCV] Compress addiw rd, x0, simm6 to c.li rd, simm6
A pattern was present for addi rd, x0, simm6 but not addiw which is
semantically identical when the source register is x0. This patch addresses
that, and the benefit can be seen in rv64c-aliases-valid.s.

llvm-svn: 343911
2018-10-06 06:09:46 +00:00
Ana Pazos 9d6c55323f [RISCV] Support named operands for CSR instructions.
Reviewers: asb, mgrang

Reviewed By: asb

Subscribers: jocewei, mgorny, jfb, PkmX, MartinMosbeck, brucehoult, the_o, rkruppe, rogfer01, rbar, johnrusso, simoncook, jordy.potman.lists, sabuasal, niosHD, kito-cheng, shiva0217, zzheng, edward-jones

Differential Revision: https://reviews.llvm.org/D46759

llvm-svn: 343822
2018-10-04 21:50:54 +00:00
Alex Bradbury 5bf3b20e99 [RISCV] Remove overzealous is64Bit checks
lowerGlobalAddress, lowerBlockAddress, and insertIndirectBranch contain 
overzealous checks for is64Bit. These functions are all safe as-implemented 
for RV64.

llvm-svn: 343781
2018-10-04 14:30:03 +00:00
Alex Bradbury e96b7c88a3 [RISCV] Bugfix for floats passed on the stack with the ILP32 ABI on RV32F
f32 values passed on the stack would previously cause an assertion in 
unpackFromMemLoc.. This would only trigger in the presence of the F extension 
making f32 a legal type. Otherwise the f32 would be legalized.

This patch fixes that by keeping LocVT=f32 when a float is passed on the 
stack. It also adds test coverage for this case, and tests that also 
demonstrate lw/sw/flw/fsw will be selected when most profitable. i.e. there is 
no unnecessary i32<->f32 conversion in registers.

llvm-svn: 343756
2018-10-04 07:28:49 +00:00
Alex Bradbury 0e16766b76 [RISCV][NFC] Fix naming of RISCVISelLowering::{LowerRETURNADDR,LowerFRAMEADDR}
Rename to lowerRETURNADDR, lowerFRAMEADDR in order to be consistent with the 
LLVM coding style and the other functions in this file.

llvm-svn: 343752
2018-10-04 05:27:50 +00:00
Alex Bradbury 5ac0a2fc48 [RISCV] Handle redundant SplitF64+BuildPairF64 pairs in a DAGCombine
r343712 performed this optimisation during instruction selection. As Eli 
Friedman pointed out in post-commit review, implementing this as a DAGCombine 
might allow opportunities for further optimisations.

llvm-svn: 343741
2018-10-03 23:30:16 +00:00
Alex Bradbury 1dbfdeb6e5 [RISCV][NFC] Refactor LocVT<->ValVT converstion in RISCVISelLowering
There was some duplicated logic for using the LocInfo of a CCValAssign in 
order to convert from the ValVT to LocVT or vice versa. Resolve this by 
factoring out convertLocVTFromValVT from unpackFromRegLoc. Also rename 
packIntoRegLoc to the more appropriate convertValVTToLocVT and call these 
helper functions consistently.

llvm-svn: 343737
2018-10-03 22:53:25 +00:00
Alex Bradbury ce9049952f [RISCV][NFCI] Handle redundant splitf64+buildpairf64 pairs during instruction selection
Although we can't write a tablegen pattern to remove redundant 
splitf64+buildf64 pairs due to the multiple return values, we can handle it 
with some C++ selection code. This is simpler than removing them after 
instruction selection through RISCVDAGToDAGISel::PostprocessISelDAG, as was 
done previously.

llvm-svn: 343712
2018-10-03 20:12:10 +00:00
Alex Bradbury d33ffe9bb1 [RISCV][NFC] Refactor RISCVDAGToDAGISel::Select
Introduce and use a switch on the opcode.

llvm-svn: 343688
2018-10-03 13:13:13 +00:00
Alex Bradbury d934032e48 [RISCV] Gate float<->int and double<->int conversion patterns on IsRV32
The patterns as defined are correct only when XLen==32.

This is another preparatory patch for a set of patches that flesh out RV64 
codegen.

llvm-svn: 343679
2018-10-03 11:35:22 +00:00
Alex Bradbury d464ed8c2e [RISCV] Remove XLenVT==i32 assumptions from RISCVInstrInfo td
1. brcond operates on an condition.
2. atomic_fence and the pseudo AMO instructions should all take xlen immediates 

This allows the same definitions and patterns to work for RV64 (XLenVT==i64).

llvm-svn: 343678
2018-10-03 11:14:26 +00:00
Alex Bradbury a9ac5994b1 [RISCV] Gate simm32 materialisation pattern and SW pattern on IsRV32
These patterns are not correct for RV64.

llvm-svn: 343677
2018-10-03 11:04:59 +00:00
Alex Bradbury 96ed75d066 [RISCV][MC] Modify evaluateConstantImm interface to allow reuse from addExpr
This is a trivial refactoring that I'm committing now as it makes a patch I'm 
about to post for review easier to follow. There is some overlap between 
evaluateConstantImm and addExpr in RISCVAsmParser. This patch allows 
evaluateConstantImm to be reused from addExpr to remove this overlap. The 
benefit will be greater when a future patch adds extra code to allows 
immediates to be evaluated from constant symbols (e.g. `.equ CONST, 0x1234`).

No functional change intended.

llvm-svn: 342641
2018-09-20 11:40:43 +00:00
Alex Bradbury 226f3ef5a5 [RISCV][MC] Improve parsing of jal/j operands
Examples such as `jal a3`, `j a3` and `jal a3, a3` are accepted by gas 
but rejected by LLVM MC. This patch rectifies this. I introduce 
RISCVAsmParser::parseJALOffset to ensure that symbol names that coincide with 
register names can safely be parsed. This is made a somewhat fiddly due to the 
single-operand alias form (see the comment in parseJALOffset for more info).

Differential Revision: https://reviews.llvm.org/D52029

llvm-svn: 342629
2018-09-20 08:10:35 +00:00
Alex Bradbury 21aea51e71 [RISCV] Codegen for i8, i16, and i32 atomicrmw with RV32A
Introduce a new RISCVExpandPseudoInsts pass to expand atomic 
pseudo-instructions after register allocation. This is necessary in order to 
ensure that register spills aren't introduced between LL and SC, thus breaking 
the forward progress guarantee for the operation. AArch64 does something 
similar for CmpXchg (though only at O0), and Mips is moving towards this 
approach (see D31287). See also [this mailing list 
post](http://lists.llvm.org/pipermail/llvm-dev/2016-May/099490.html) from 
James Knight, which summarises the issues with lowering to ll/sc in IR or 
pre-RA.

See the [accompanying RFC 
thread](http://lists.llvm.org/pipermail/llvm-dev/2018-June/123993.html) for an 
overview of the lowering strategy.

Differential Revision: https://reviews.llvm.org/D47882

llvm-svn: 342534
2018-09-19 10:54:22 +00:00
Alex Bradbury 68f73c1206 [RISCV][MC] Use a custom ParserMethod for the bare_symbol operand type
This allows the hard-coded shouldForceImmediate logic to be removed because 
the generated MatchOperandParserImpl makes use of the current context (i.e. 
the current mnemonic) to determine parsing behaviour, and so won't first try 
to parse a register before parsing a symbol name.

No functional change is intended. gas accepts immediate arguments for call, 
tail and lla. This patch doesn't address this discrepancy.

Differential Revision: https://reviews.llvm.org/D51733

llvm-svn: 342488
2018-09-18 15:18:16 +00:00
Alex Bradbury 7d0e18d0dd [RISCV][MC] Reject bare symbols for the simm12 operand type
addi a0, a0, foo and lw a0, foo(a0) and similar are now rejected. An explicit 
%lo and %pcrel_lo modifier is required. This matches gas behaviour.

llvm-svn: 342487
2018-09-18 15:13:29 +00:00
Alex Bradbury 74340f1805 [RISCV][MC] Tighten up checking of sybol operands to lui and auipc
Reject bare symbols and accept only %pcrel_hi(sym) for auipc and %hi(sym) for 
lui. Also test valid operand modifiers in rv32i-valid.s.

Note this is slightly stricter than gas, which will accept either %pcrel_hi or 
%hi for both lui and auipc.

Differential Revision: https://reviews.llvm.org/D51731

llvm-svn: 342486
2018-09-18 15:08:35 +00:00
Ana Pazos 065b088759 [RISCV][MC] Reject bare symbols for the simm6 and simm6nonzero operand types
Summary:
Fixed assertions due to invalid fixup when encoding compressed instructions
 (c.addi, c.addiw, c.li, c.andi) with bare symbols with/without modifiers.
  This matches GAS behavior as well.

This bug was uncovered by a LLVM MC Disassembler Protocol Buffer Fuzzer
for the RISC-V assembly language.

Reviewers: asb

Reviewed By: asb

Subscribers: rbar, johnrusso, simoncook, sabuasal, niosHD, kito-cheng, shiva0217, zzheng, edward-jones, mgrang, rogfer01, MartinMosbeck, brucehoult, the_o, rkruppe, PkmX, jocewei, asb

Differential Revision: https://reviews.llvm.org/D52005

llvm-svn: 342160
2018-09-13 18:37:23 +00:00
Ana Pazos b0799dda77 [RISCV] Fix decoding of invalid instruction with C extension enabled.
Summary:
The illegal instruction 0x00 0x00 is being wrongly decoded as
c.addi4spn with 0 immediate.

The invalid instruction 0x01 0x61 is being wrongly decoded as
c.addi16sp with 0 immediate.

This bug was uncovered by a LLVM MC Disassembler Protocol Buffer Fuzzer
for the RISC-V assembly language.

Reviewers: asb

Reviewed By: asb

Subscribers: rbar, johnrusso, simoncook, sabuasal, niosHD, kito-cheng, shiva0217, zzheng, edward-jones, mgrang, rogfer01, MartinMosbeck, brucehoult, the_o, rkruppe, PkmX, jocewei, asb

Differential Revision: https://reviews.llvm.org/D51815

llvm-svn: 342159
2018-09-13 18:21:19 +00:00
Benjamin Kramer 27c769d28a [Target] Untangle disassemblers
Disassemblers cannot depend on main target headers. The same is true for
MCTargetDesc, but there's a lot more cleanup needed for that.

llvm-svn: 341822
2018-09-10 12:53:46 +00:00
Ana Pazos b2ed11a086 [RISCV] Fix crash in decoding instruction with unknown floating point rounding mode
Summary:
Instead of crashing in printFRMArg, decode and warn about invalid instruction.

This bug was uncovered by a LLVM MC Disassembler Protocol Buffer Fuzzer
for the RISC-V assembly language.

Reviewers: asb

Reviewed By: asb

Subscribers: rbar, johnrusso, simoncook, sabuasal, niosHD, kito-cheng, shiva0217, zzheng, edward-jones, mgrang, rogfer01, MartinMosbeck, brucehoult, the_o, rkruppe, PkmX, jocewei, asb

Differential Revision: https://reviews.llvm.org/D51705

llvm-svn: 341691
2018-09-07 18:43:43 +00:00
Ana Pazos b97d18945b [RISCV] Fix AddressSanitizer heap-buffer-overflow in disassembling
Summary:
RISCVDisassembler should check number of bytes available before reading them.
Crash noticed when enabling -DLLVM_USE_SANITIZER=Address.

This bug was uncovered by a LLVM MC Disassembler Protocol Buffer Fuzzer for the RISC-V assembly language.

Reviewers: asb

Reviewed By: asb

Subscribers: rbar, johnrusso, simoncook, sabuasal, niosHD, kito-cheng, shiva0217, zzheng, edward-jones, mgrang, rogfer01, MartinMosbeck, brucehoult, the_o, rkruppe, PkmX, jocewei, asb

Differential Revision: https://reviews.llvm.org/D51708

llvm-svn: 341686
2018-09-07 18:23:19 +00:00
Ana Pazos 6b34051b33 [RISCV] Fixed SmallVector.h Assertion `idx < size()'
Summary:

RISCVAsmParser needs to handle the case the error message is of specific type, other than the generic Match_InvalidOperand, and the corresponding
operand is missing.

This bug was uncovered by a LLVM MC Assembler Protocol Buffer Fuzzer  for the RISC-V assembly language.

Reviewers: asb

Reviewed By: asb

Subscribers: llvm-commits, jocewei, asb, rbar, johnrusso, simoncook, sabuasal, niosHD, kito-cheng, shiva0217, zzheng, edward-jones, mgrang, rogfer01, MartinMosbeck, brucehoult, the_o, PkmX

Differential Revision: https://reviews.llvm.org/D50790

llvm-svn: 341104
2018-08-30 19:43:19 +00:00
Roger Ferrer Ibanez fe28217048 [RISCV] atomic_store_nn have a different layout to regular store
We cannot directy reuse the patterns of StPat because for some reason the store
DAG node and the atomic_store_nn DAG nodes put the ptr and the value in
different positions. Currently we attempt to store the address to an address
formed by the value.

Differential Revision: https://reviews.llvm.org/D51217

llvm-svn: 340722
2018-08-27 07:08:18 +00:00
Ana Pazos ecc65eddec [RISCV] Fixed Assertion`Kind == Immediate && "Invalid type access!"' failed.
Summary:
Missing check for isImm() in some Immediate classes.

This bug was uncovered by a LLVM MC Assembler Protocol Buffer Fuzzer
for the RISC-V assembly language.

Reviewers: hiraditya, asb

Reviewed By: hiraditya, asb

Subscribers: llvm-commits, hiraditya, kito-cheng, shiva0217, rkruppe, asb, rbar, johnrusso, simoncook, sabuasal, niosHD, zzheng, edward-jones, mgrang, rogfer01, MartinMosbeck, brucehoult, the_o, PkmX, jocewei

Differential Revision: https://reviews.llvm.org/D50797

llvm-svn: 340674
2018-08-24 23:47:49 +00:00
Ana Pazos 61b28ede75 [RISCV] Fix std::advance slowness
Summary:
It seems std::advance template is treating "-MFI.getCalleeSavedInfo().size()"
as a large unsigned value", causing slowness.

Thanks to Henrik Gustafsson for reporting the issue.

Reviewers: asb

Reviewed By: asb

Subscribers: llvm-commits, rbar, johnrusso, simoncook, sabuasal, niosHD, kito-cheng, shiva0217, zzheng, edward-jones, mgrang, rogfer01, MartinMosbeck, brucehoult, the_o, rkruppe, PkmX, jocewei, asb

Differential Revision: https://reviews.llvm.org/D51148

llvm-svn: 340669
2018-08-24 23:13:59 +00:00
Roger Ferrer Ibanez 734a04ea33 [RISCV] Remove unused function
This function is not virtual, it is private and it is not called anywhere. No
regression is introduced by removing it.

I think we can safely remove it.

Differential Revision: https://reviews.llvm.org/D50836

llvm-svn: 340024
2018-08-17 13:40:03 +00:00
Roger Ferrer Ibanez c8f4dbbc63 [RISCV] Fix incorrect use of MCInstBuilder
This is a fix for r339314.

MCInstBuilder uses the named parameter idiom and an 'operator MCInst&' to ease
the creation of MCInsts. As the object of MCInstBuilder owns the MCInst is
manipulating, the lifetime of the MCInst is bound to that of MCInstBuilder.

In r339314 I bound a reference to the MCInst in an initializer. The
temporary of MCInstBuilder (and also its MCInst) is destroyed at the end of
the declaration leading to a dangling reference.

Fix this by using MCInstBuilder inside an argument of a function call.
Temporaries in function calls are destroyed in the enclosing full expression,
so the the reference to MCInst is still valid when emitToStreamer executes.

llvm-svn: 339654
2018-08-14 08:30:42 +00:00
Chih-Mao Chen 5d94b25ffe Test commit: fix punctuation
llvm-svn: 339652
2018-08-14 08:08:39 +00:00
Ana Pazos 10de234905 [RISC-V] Fixed alias for addi x2, x2, 0
A missing check for non-zero immediate in MCOperandPredicate
caused c.addi16sp sp, 0 to be selected which is not a valid
instruction.

llvm-svn: 339381
2018-08-09 20:51:53 +00:00
Roger Ferrer Ibanez 577a97e2b9 [RISCV] Add "lla" pseudo-instruction to assembler
This pseudo-instruction is similar to la but uses PC-relative addressing
unconditionally. This is, la is only different to lla when using -fPIC. This
pseudo-instruction seems often forgotten in several specs but it is definitely
mentioned in binutils opcodes/riscv-opc.c. The semantics are defined both in
page 37 of the "RISC-V Reader" book but also in function macro found in
gas/config/tc-riscv.c.

This is a very first step towards adding PIC support for Linux in the RISC-V
backend.

The lla pseudo-instruction expands to a sequence of auipc + addi with a couple
of pc-rel relocations where the second points to the first one. This is
described in
https://github.com/riscv/riscv-elf-psabi-doc/blob/master/riscv-elf.md#pc-relative-symbol-addresses

For now, this patch only introduces support of that pseudo instruction at the
assembler parser.

Differential Revision: https://reviews.llvm.org/D49661

llvm-svn: 339314
2018-08-09 07:08:20 +00:00
Alex Bradbury 07224dfb47 [RISCV] Add mnemonic alias: move, sbreak and scall.
Further improve compatibility with the GNU assembler.

Differential Revision: https://reviews.llvm.org/D50217
Patch by Kito Cheng.

llvm-svn: 339255
2018-08-08 14:53:45 +00:00
Alex Bradbury 7d8d87c143 [RISCV] Add InstAlias definitions for add[w], and, xor, or, sll[w], srl[w], sra[w], slt and sltu with immediate
Match the GNU assembler in supporting immediate operands for these 
instructions even when the reg-reg mnemonic is used.

Differential Revision: https://reviews.llvm.org/D50046
Patch by Kito Cheng.

llvm-svn: 339252
2018-08-08 14:45:44 +00:00
Kito Cheng dffce953bf Test commit.
llvm-svn: 338672
2018-08-02 05:38:18 +00:00
Ana Pazos 2e4106b73d [RISCV] Add support for _interrupt attribute
- Save/restore only registers that are used.
This includes Callee saved registers and Caller saved registers
(arguments and temporaries) for integer and FP registers.
- If there is a call in the interrupt handler, save/restore all
Caller saved registers (arguments and temporaries) and all FP registers.
- Emit special return instructions depending on "interrupt"
attribute type.
Based on initial patch by Zhaoshi Zheng.

Reviewers: asb

Reviewed By: asb

Subscribers: rkruppe, the_o, MartinMosbeck, brucehoult, rbar, johnrusso, simoncook, sabuasal, niosHD, kito-cheng, shiva0217, zzheng, edward-jones, mgrang, rogfer01, llvm-commits

Differential Revision: https://reviews.llvm.org/D48411

llvm-svn: 338047
2018-07-26 17:49:43 +00:00
Sameer AbuAsal 9b65ffb097 [RISCV] Add machine function pass to merge base + offset
Summary:
   In r333455 we added a peephole to fix the corner cases that result
   from separating base + offset lowering of global address.The
   peephole didn't handle some of the cases because it only has a basic
   block view instead of a function level view.

   This patch replaces that logic with a machine function pass. In
   addition to handling the original cases it handles uses of the global
   address across blocks in function and folding an offset from LW\SW
   instruction. This pass won't run for OptNone compilation, so there
   will be a negative impact overall vs the old approach at O0.

Reviewers: asb, apazos, mgrang

Reviewed By: asb

Subscribers: MartinMosbeck, brucehoult, the_o, rogfer01, mgorny, rbar, johnrusso, simoncook, niosHD, kito-cheng, shiva0217, zzheng, llvm-commits, edward-jones

Differential Revision: https://reviews.llvm.org/D47857

llvm-svn: 335786
2018-06-27 20:51:42 +00:00
Sameer AbuAsal e01e711c64 [RISCV] Tail calls don't need to save return address
Summary:
 When expanding the PseudoTail in expandFunctionCall() we were using X6
 to save the return address. Since this is a tail call the return
 address is not needed, this patch replaces it with X0 to be ignored.

 This matches the behaviour listed in the ISA V2.2 document page 110.
 tail offset -----> jalr x0, x6, offset

 GCC exhibits the same behavior.

Reviewers: apazos, asb, mgrang

Reviewed By: asb

Subscribers: rbar, johnrusso, simoncook, niosHD, kito-cheng, shiva0217, zzheng, edward-jones, rogfer01

Differential Revision: https://reviews.llvm.org/D48343

llvm-svn: 335239
2018-06-21 14:37:09 +00:00
Alex Bradbury fafdebcfcb [RISCV] Accept fmv.s.x and fmv.x.s as mnemonic aliases for fmv.w.x and fmv.x.w
These instructions were renamed in version 2.2 of the user-level ISA spec, but 
the old name should also be accepted by standard tools.

llvm-svn: 335154
2018-06-20 18:42:25 +00:00
Alex Bradbury 79d2b50ca8 [RISCV] Add InstAlias definitions for fgt.{s|d}, fge.{s|d}
These are produced by GCC and supported by GAS, but not currently contained in 
the pseudoinstruction listing in the RISC-V ISA manual.

llvm-svn: 335127
2018-06-20 14:03:02 +00:00
Alex Bradbury 18b9bd7d6c [RISCV] Add InstAlias definitions for sgt and sgtu
These are produced by GCC and supported by GAS, but not currently contained in 
the pseudoinstruction listing in the RISC-V ISA manual.

llvm-svn: 335120
2018-06-20 12:54:02 +00:00
Alex Bradbury 96f492d7df [RISCV] Add codegen support for atomic load/stores with RV32A
Fences are inserted according to table A.6 in the current draft of version 2.3
of the RISC-V Instruction Set Manual, which incorporates the memory model
changes and definitions contributed by the RISC-V Memory Consistency Model
task group.

Instruction selection failures will now occur for 8/16/32-bit atomicrmw and 
cmpxchg operations when targeting RV32IA until lowering for these operations 
is added in a follow-on patch.

Differential Revision: https://reviews.llvm.org/D47589

llvm-svn: 334591
2018-06-13 12:04:51 +00:00
Alex Bradbury dc790dd5d0 [RISCV] Codegen support for atomic operations on RV32I
This patch adds lowering for atomic fences and relies on AtomicExpandPass to
lower atomic loads/stores, atomic rmw, and cmpxchg to __atomic_* libcalls.

test/CodeGen/RISCV/atomic-* are modelled on the exhaustive
test/CodeGen/PPC/atomics-regression.ll, and will prove more useful once RV32A
codegen support is introduced.

Fence mappings are taken from table A.6 in the current draft of version 2.3 of
the RISC-V Instruction Set Manual, which incorporates the memory model changes
and definitions contributed by the RISC-V Memory Consistency Model task group.

Differential Revision: https://reviews.llvm.org/D47587

llvm-svn: 334590
2018-06-13 11:58:46 +00:00
Alex Bradbury ed53ca73ec [RISCV] Implement MC layer support for the fence.tso instruction
The instruction makes use of a previously ignored field in the fence
instruction. It is introduced in the version 2.3 draft of the RISC-V
specification after much work by the Memory Model Task Group.

As clarified here <https://github.com/riscv/riscv-isa-manual/issues/186>,
the fence.tso assembler mnemonic does not have operands.

llvm-svn: 334278
2018-06-08 10:39:05 +00:00
Alex Bradbury 6a4b5441e4 [RISCV] AsmParser support for the li pseudo instruction
The implementation follows the MIPS backend and expands the pseudo instruction 
directly during asm parsing. As the result, only real MC instructions are 
emitted to the MCStreamer. The actual expansion to real instructions is 
similar to the expansion performed by the GNU Assembler.

This patch supersedes D41949.

Differential Revision: https://reviews.llvm.org/D46118
Patch by Mario Werner.

llvm-svn: 334203
2018-06-07 15:35:47 +00:00
Ilya Biryukov 3c9c10649b Fix compilation of WebAssembly and RISCV after r334078
llvm-svn: 334085
2018-06-06 10:57:50 +00:00
Amaury Sechet 8467411dad Set ADDE/ADDC/SUBE/SUBC to expand by default
Summary:
They've been deprecated in favor of UADDO/ADDCARRY or USUBO/SUBCARRY for a while.

Target that uses these opcodes are changed in order to ensure their behavior doesn't change.

Reviewers: efriedma, craig.topper, dblaikie, bkramer

Subscribers: jholewinski, arsenm, jyknight, sdardis, nemanjai, nhaehnle, kbarton, fedor.sergeev, asb, rbar, johnrusso, simoncook, jordy.potman.lists, apazos, sabuasal, niosHD, jrtc27, zzheng, edward-jones, mgrang, atanasyan, llvm-commits

Differential Revision: https://reviews.llvm.org/D47422

llvm-svn: 333748
2018-06-01 13:21:33 +00:00
Shiva Chen c3d0e89284 [RISCV] Support resolving fixup_riscv_call and add to MCFixupKindInfo table
Resolving fixup_riscv_call by assembler when the linker relaxation diabled
and the function and callsite within the same compile unit.

And also adding static_assert after Infos array declaration
to avoid missing any new fixup in MCFixupKindInfo in the future.

Differential Revision: https://reviews.llvm.org/D47126

llvm-svn: 333487
2018-05-30 01:16:36 +00:00
Sameer AbuAsal 97684419e8 [RISCV] Add peepholes for Global Address lowering patterns
Summary:
  Base and offset are always separated when a GlobalAddress node is lowered
  (rL332641) as an optimization to reduce instruction count. However, this
  optimization is not profitable if the Global Address ends up being used in only
  instruction.

  This patch adds peephole optimizations that merge an offset of
  an address calculation into the LUI %%hi and ADD %lo of the lowering sequence.

  The peephole handles three patterns:

 1) ADDI (ADDI (LUI %hi(global)) %lo(global)), offset
     --->
      ADDI (LUI %hi(global + offset)) %lo(global + offset).

   This generates:
   lui a0, hi (global + offset)
   add a0, a0, lo (global + offset)

   Instead of

   lui a0, hi (global)
   addi a0, hi (global)
   addi a0, offset

   This pattern is for cases when the offset is small enough to fit in the
   immediate filed of ADDI (less than 12 bits).

 2) ADD ((ADDI (LUI %hi(global)) %lo(global)), (LUI hi_offset))
     --->
      offset = hi_offset << 12
      ADDI (LUI %hi(global + offset)) %lo(global + offset)

   Which generates the ASM:

   lui  a0, hi(global + offset)
   addi a0, lo(global + offset)

   Instead of:

   lui  a0, hi(global)
   addi a0, lo(global)
   lui a1, (offset)
   add a0, a0, a1

   This pattern is for cases when the offset doesn't fit in an immediate field
   of ADDI but the lower 12 bits are all zeros.

 3) ADD ((ADDI (LUI %hi(global)) %lo(global)), (ADDI lo_offset, (LUI hi_offset)))
     --->
        offset = global + offhi20<<12 + offlo12
        ADDI (LUI %hi(global + offset)) %lo(global + offset)

   Which generates the ASM:

   lui  a1, %hi(global + offset)
   addi a1, %lo(global + offset)

   Instead of:

   lui  a0, hi(global)
   addi a0, lo(global)
   lui a1, (offhi20)
   addi a1, (offlo12)
   add a0, a0, a1

   This pattern is for cases when the offset doesn't fit in an immediate field
   of ADDI and both the lower 1 bits and high 20 bits are non zero.

    Reviewers: asb

    Reviewed By: asb

    Subscribers: rbar, johnrusso, simoncook, jordy.potman.lists, apazos,
  niosHD, kito-cheng, shiva0217, zzheng, edward-jones, mgrang

llvm-svn: 333455
2018-05-29 19:34:54 +00:00
Shiva Chen 43bfe84451 [RISCV] Support linker relax function call from auipc and jalr to jal
To do this:
1. Add fixup_riscv_relax fixup types which eventually will
   transfer to R_RISCV_RELAX relocation types.

2. Insert R_RISCV_RELAX relocation types to auipc function call
   expression when linker relaxation enabled.

Differential Revision: https://reviews.llvm.org/D44886

llvm-svn: 333158
2018-05-24 06:21:23 +00:00
Mandeep Singh Grang ddcb95664e [RISCV] Lower the tail pseudoinstruction
This patch lowers the tail pseudoinstruction. This has been modeled after ARM's
tail call opt.

llvm-svn: 333137
2018-05-23 22:44:08 +00:00
Sameer AbuAsal eadce02741 [RISCV] Set CostPerUse for registers
Summary:
 Set CostPerUse higher for registers that are not used in the compressed
 instruction set. This will influence the greedy register allocator to reduce
 the use of registers that can't be encoded in 16 bit instructions. This
 affects register allocation even when compressed instruction isn't targeted,
 we see no major negative codegen impact.

Reviewers: asb

Reviewed By: asb

Subscribers: rbar, johnrusso, simoncook, jordy.potman.lists, apazos, niosHD, kito-cheng, shiva0217, zzheng, edward-jones, mgrang

Differential Revision: https://reviews.llvm.org/D47039

llvm-svn: 333132
2018-05-23 21:34:30 +00:00
Alex Bradbury 257d5b5639 [RISCV] Add symbol diff relocation support for RISC-V
For RISC-V it is desirable to have relaxation happen in the linker once 
addresses are known, and as such the size between two instructions/byte 
sequences in a section could change.

For most assembler expressions, this is fine, as the absolute address results 
in the expression being converted to a fixup, and finally relocations. 
However, for expressions such as .quad .L2-.L1, the assembler folds this down 
to a constant once fragments are laid out, under the assumption that the 
difference can no longer change, although in the case of linker relaxation the 
differences can change at link time, so the constant is incorrect. One place 
where this commonly appears is in debug information, where the size of a 
function expression is in a form similar to the above.

This patch extends the assembler to allow an AsmBackend to declare that it 
does not want the assembler to fold down this expression, and instead generate 
a pair of relocations that allow the linker to carry out the calculation. In 
this case, the expression is not folded, but when it comes to emitting a 
fixup, the generic FK_Data_* fixups are converted into a pair, one for the 
addition half, one for the subtraction, and this is passed to the relocation 
generating methods as usual. I have named these FK_Data_Add_* and 
FK_Data_Sub_* to indicate which half these are for.

For RISC-V, which supports this via e.g. the R_RISCV_ADD64, R_RISCV_SUB64 pair 
of relocations, these are also set to always emit relocations relative to 
local symbols rather than section offsets. This is to deal with the fact that 
if relocations were calculated on e.g. .text+8 and .text+4, the result 12 
would be stored rather than 4 as both addends are added in the linker.

Differential Revision: https://reviews.llvm.org/D45181
Patch by Simon Cook.

llvm-svn: 333079
2018-05-23 12:36:18 +00:00
Alex Bradbury 1c010d0fa4 [RISCV] Correctly report sizes for builtin fixups
This is a different approach to fixing the problem described in D46746. 
RISCVAsmBackend currently depends on the getSize helper function returning the 
number of bytes a fixup may change (note: some other backends have a similar 
helper named getFixupNumKindBytes). As noted in that review, this doesn't 
return the correct size for FK_Data_1, FK_Data_2, or FK_Data_8 meaning that 
too few bytes will be written in the case of FK_Data_8, and there's the 
potential of writing outside the Data array for the smaller fixups.

D46746 extends getSize to recognise some of the builtin fixup types. Rather 
than having a function that needs to be kept up to date as new builtin or 
target-specific fixups are added, We can calculate an appropriate bound on the 
number of bytes that might be touched using Info.TargetSize and 
Info.TargetOffset.

Differential Revision: https://reviews.llvm.org/D46965

llvm-svn: 333076
2018-05-23 10:53:56 +00:00
Peter Collingbourne dcd7d6c331 MC: Separate creating a generic object writer from creating a target object writer. NFCI.
With this we gain a little flexibility in how the generic object
writer is created.

Part of PR37466.

Differential Revision: https://reviews.llvm.org/D47045

llvm-svn: 332868
2018-05-21 19:20:29 +00:00
Peter Collingbourne 571a3301ae MC: Change MCAsmBackend::writeNopData() to take a raw_ostream instead of an MCObjectWriter. NFCI.
To make this work I needed to add an endianness field to MCAsmBackend
so that writeNopData() implementations know which endianness to use.

Part of PR37466.

Differential Revision: https://reviews.llvm.org/D47035

llvm-svn: 332857
2018-05-21 17:57:19 +00:00
Peter Collingbourne e3f652973e Support: Simplify endian stream interface. NFCI.
Provide some free functions to reduce verbosity of endian-writing
a single value, and replace the endianness template parameter with
a field.

Part of PR37466.

Differential Revision: https://reviews.llvm.org/D47032

llvm-svn: 332757
2018-05-18 19:46:24 +00:00
Shiva Chen 6e07dfb148 [RISCV] Add WasForced parameter to MCAsmBackend::fixupNeedsRelaxationAdvanced
For RISCV branch instructions, we need to preserve relocation types when linker
relaxation enabled, so then linker could modify offset when the branch offsets
changed.

We preserve relocation types by define shouldForceRelocation.
IsResolved return by evaluateFixup will always false when shouldForceRelocation
return true. It will make RISCV MC Branch Relaxation always relax 16-bit
branches to 32-bit form, even if the symbol actually could be resolved.

To avoid 16-bit branches always relax to 32-bit form when linker relaxation
enabled, we add a new parameter WasForced to indicate that the symbol actually
couldn't be resolved and not forced by shouldForceRelocation return true.

RISCVAsmBackend::fixupNeedsRelaxationAdvanced could relax branches with
unresolved symbols by (!IsResolved && !WasForced).

RISCV MC Branch Relaxation is needed because RISCV could perform 32-bit
to 16-bit transformation in MC layer.

Differential Revision: https://reviews.llvm.org/D46350

llvm-svn: 332696
2018-05-18 06:42:21 +00:00
Sameer AbuAsal 1dc0a8fb18 [RISCV] Separate base from offset in lowerGlobalAddress
Summary:
When lowering global address, lower the base as a TargetGlobal first then
 create an SDNode for the offset separately and chain it to the address calculation

 This optimization will create a DAG where the base address of a global access will
 be reused between different access. The offset can later be folded into the immediate
 part of the memory access instruction.

  With this optimization we generate:

    lui a0, %hi(s)
    addi a0, a0, %lo(s) ; shared base address.

    addi a1, zero, 20 ; 2 instructions per access.
    sw a1, 44(a0)

    addi a1, zero, 10
    sw a1, 8(a0)

    addi a1, zero, 30
    sw a1, 80(a0)

    Instead of:

    lui a0, %hi(s+44) ; 3 instructions per access.
    addi a1, zero, 20
    sw a1, %lo(s+44)(a0)

    lui a0, %hi(s+8)
    addi a1, zero, 10
    sw a1, %lo(s+8)(a0)

    lui a0, %hi(s+80)
    addi a1, zero, 30
    sw a1, %lo(s+80)(a0)

    Which will save one instruction per access.

Reviewers: asb, apazos

Reviewed By: asb

Subscribers: rbar, johnrusso, simoncook, jordy.potman.lists, niosHD, kito-cheng, shiva0217, zzheng, edward-jones, mgrang, apazos, asb, llvm-commits

Differential Revision: https://reviews.llvm.org/D46989

llvm-svn: 332641
2018-05-17 18:14:53 +00:00
Mandeep Singh Grang ef0ebf2806 [RISCV] Implement MC layer support for the tail pseudoinstruction
Summary:
This patch implements MC support for tail psuedo instruction.
A follow-up patch implements the codegen support as well as handling of the indirect tail pseudo instruction.

Reviewers: asb, apazos

Reviewed By: asb

Subscribers: rbar, johnrusso, simoncook, jordy.potman.lists, sabuasal, niosHD, kito-cheng, shiva0217, zzheng, edward-jones, llvm-commits

Differential Revision: https://reviews.llvm.org/D46221

llvm-svn: 332634
2018-05-17 17:31:27 +00:00
Alex Bradbury 6a53023b4e [RISCV] Set isReMaterializable on ADDI and LUI instructions
The isReMaterlizable flag is somewhat confusing, unlike most other instruction 
flags it is currently interpreted as a hint (mightBeRematerializable would be 
a better name). While LUI is always rematerialisable, for an instruction like 
ADDI it depends on its operands. TargetInstrInfo::isTriviallyReMaterializable 
will call TargetInstrInfo::isReallyTriviallyReMaterializable, which in turn 
calls TargetInstrInfo::isReallyTriviallyReMaterializableGeneric. We rely on 
the logic in the latter to pick out instances of ADDI that really are 
rematerializable.

The isReMaterializable flag does make a difference on a variety of test 
programs. The recently committed remat.ll test case demonstrates how stack 
usage is reduce and a unnecessary lw/sw can be removed. Stack usage in the 
Proc0 function in dhrystone reduces from 192 bytes to 112 bytes.

For the sake of completeness, this patch also implements 
RISCVRegisterInfo::isConstantPhysReg. Although this is called from a number of 
places, it doesn't seem to result in different codegen for any programs I've 
thrown at it. However, it is called in the rematerialisation codepath and it 
seems sensible to implement something correct here.

Differential Revision: https://reviews.llvm.org/D46182

llvm-svn: 332617
2018-05-17 15:51:37 +00:00
Alex Bradbury cea6db0480 [RISCV] Add support for .half, .hword, .word, .dword directives
These directives are recognised by gas. Support is added through the use of 
addAliasForDirective.

Also match RISC-V gcc in preferring .half and .word for 16-bit and 32-bit data 
directives.

llvm-svn: 332574
2018-05-17 05:58:08 +00:00
Shiva Chen 3969425081 [RISCV] Define FeatureRelax and shouldForceRelocation for RISCV linker relaxation
1. Deine FeatureRelax to enable/disable linker relaxation.

2. Define shouldForceRelocation to preserve relocation types even if the fixup
   can be resolved when linker relaxation enabled. This is necessary for
   correctness as offsets may change during relaxation.

Differential Revision: https://reviews.llvm.org/D46674

llvm-svn: 332318
2018-05-15 01:28:50 +00:00
Nicola Zaghen d34e60ca85 Rename DEBUG macro to LLVM_DEBUG.
The DEBUG() macro is very generic so it might clash with other projects.
The renaming was done as follows:
- git grep -l 'DEBUG' | xargs sed -i 's/\bDEBUG\s\?(/LLVM_DEBUG(/g'
- git diff -U0 master | ../clang/tools/clang-format/clang-format-diff.py -i -p1 -style LLVM
- Manual change to APInt
- Manually chage DOCS as regex doesn't match it.

In the transition period the DEBUG() macro is still present and aliased
to the LLVM_DEBUG() one.

Differential Revision: https://reviews.llvm.org/D43624

llvm-svn: 332240
2018-05-14 12:53:11 +00:00
Alex Bradbury bca0c3cdb6 [RISCV] Support .option rvc and norvc assembler directives
These directives allow the 'C' (compressed) extension to be enabled/disabled 
within a single file.

Differential Revision: https://reviews.llvm.org/D45864
Patch by Kito Cheng

llvm-svn: 332107
2018-05-11 17:30:28 +00:00
Craig Topper 781aa181ab Fix a bunch of places where operator-> was used directly on the return from dyn_cast.
Inspired by r331508, I did a grep and found these.

Mostly just change from dyn_cast to cast. Some cases also showed a dyn_cast result being converted to bool, so those I changed to isa.

llvm-svn: 331577
2018-05-05 01:57:00 +00:00
Alex Bradbury fda6037e98 [RISCV] Implement isLoadFromStackSlot and isStoreToStackSlot
This causes some slight shuffling but no meaningful codegen differences on the 
corpus I used for testing, but it has a larger impact when combined with e.g. 
rematerialisation. Regardless, it makes sense to report as accurate 
target-specific information as possible.

llvm-svn: 330949
2018-04-26 15:34:27 +00:00
Alex Bradbury 15e894baee [RISCV] Implement isZextFree
This returns true for 8-bit and 16-bit loads, allowing LBU/LHU to be selected
and avoiding unnecessary masks.

llvm-svn: 330943
2018-04-26 14:04:18 +00:00
Alex Bradbury 130b8b3f2b [RISCV] Implement isTruncateFree
Adapted from ARM's implementation introduced in r313533 and r314280.

llvm-svn: 330940
2018-04-26 13:37:00 +00:00
Alex Bradbury dcbff63c24 [RISCV] Implement isLegalICmpImmediate
I'm unable to construct a representative test case that demonstrates the 
advantage, but it seems sensible to report accurate target-specific 
information regardless.

llvm-svn: 330938
2018-04-26 13:15:17 +00:00
Alex Bradbury 5c41ecedf8 [RISCV] Implement isLegalAddImmediate
This causes a trivial improvement in the recently added lsr-legaladdimm.ll 
test case.

llvm-svn: 330937
2018-04-26 13:00:37 +00:00
Alex Bradbury 09926296df [RISCV] Implement isLegalAddressingMode for RISC-V
This has no impact on codegen for the current RISC-V unit tests or my small 
benchmark set and very minor changes in a few programs in the GCC torture 
suite. Based on this, I haven't been able to produce a representative test 
program that demonstrates a benefit from isLegalAddressingMode. I'm committing 
the patch anyway, on the basis that presenting accurate information to the 
target-independent code is preferable to relying on incorrect generic 
assumptions.

llvm-svn: 330932
2018-04-26 12:13:48 +00:00
Alex Bradbury cd8688a4c2 [RISCV] Allow call pseudoinstruction to be used to call a function name that coincides with a register name
Previously `call zero`, `call f0` etc would fail. This leads to compilation 
failures if building programs that define functions with those names and using 
-save-temps.

llvm-svn: 330846
2018-04-25 17:25:29 +00:00
Shiva Chen d58bd8dc4a [RISCV] Expand function call to "call" pseudoinstruction
To do this:
1. Change GlobalAddress SDNode to TargetGlobalAddress to avoid legalizer
   split the symbol.

2. Change ExternalSymbol SDNode to TargetExternalSymbol to avoid legalizer
   split the symbol.

3. Let PseudoCALL match direct call with target operand TargetGlobalAddress
   and TargetExternalSymbol.

Differential Revision: https://reviews.llvm.org/D44885

llvm-svn: 330827
2018-04-25 14:19:12 +00:00