Commit Graph

52 Commits

Author SHA1 Message Date
Alex Richardson 8cf6778d30 [RISC-V] Implement RISCVInstrInfo::isCopyInstrImpl()
This does not result in changes for any of the current tests, but it might
improve debug information in some cases.

Reviewed By: luismarques

Differential Revision: https://reviews.llvm.org/D86522
2020-09-21 10:21:11 +01:00
Alex Richardson 5ba4d0365b [RISC-V] fmv.s/fmv.d should be as cheap as a move
Since the canonical floatig-point move is fsgnj rd, rs, rs, we should
handle this case in RISCVInstrInfo::isAsCheapAsAMove().

Reviewed By: lenary

Differential Revision: https://reviews.llvm.org/D86518
2020-08-27 10:32:23 +01:00
Alex Richardson 2259ce8c91 [RISC-V] ADDI/ORI/XORI x, 0 should be as cheap as a move
The isTriviallyRematerializable hook is only called for instructions that are
tagged as isAsCheapAsAMove. Since ADDI 0 is used for "mv" it should definitely
be marked with "isAsCheapAsAMove". This change avoids one stack spill in most of
the atomic-rmw.ll tests functions. It also avoids stack spills in two of our
out-of-tree CHERI tests.
ORI/XORI with zero may or may not be the same as a move micro-architecturally,
but since we are already doing it for register == x0, we might as well
do the same if the immediate is zero.

Reviewed By: luismarques

Differential Revision: https://reviews.llvm.org/D86480
2020-08-27 10:32:22 +01:00
Sam Elliott 5f9ecc5d85 [RISCV] Indirect branch generation in position independent code
This fixes the "Unable to insert indirect branch" fatal error sometimes
seen when generating position-independent code.

Patch by msizanoen1

Reviewed By: jrtc27

Differential Revision: https://reviews.llvm.org/D84833
2020-08-17 13:09:26 +01:00
Jessica Clarke 3382c243ba [RISCV] Fix RISCVInstrInfo::getInstSizeInBytes for atomics pseudos
Summary:
Without these, the generic branch relaxation pass will underestimate the
range required for branches spanning these and we can end up with
"fixup value out of range" errors rather than relaxing the branches.
Some of the instructions in the expansion may end up being compressed
but exactly determining that is awkward, and these conservative values
should be safe, if slightly suboptimal in rare cases.

Reviewers: asb, lenary, luismarques, lewis-revill

Reviewed By: asb, luismarques

Subscribers: hiraditya, rbar, johnrusso, simoncook, sabuasal, niosHD, kito-cheng, shiva0217, MaskRay, zzheng, edward-jones, rogfer01, MartinMosbeck, brucehoult, the_o, rkruppe, jfb, PkmX, jocewei, psnobl, benna, Jim, s.egerton, pzheng, sameer.abuasal, apazos, evandro, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D77443
2020-07-15 10:50:55 +01:00
Roger Ferrer Ibanez 0cbdd2a82a [RISCV] Fix isStoreToStackSlot
Because of the layout of stores (that don't have a destination operand)
this check is exactly the same as the one in
RISCVInstrInfo::isLoadFromStackSlot.

Differential Revision: https://reviews.llvm.org/D81805
2020-07-14 12:36:42 +00:00
Eli Friedman 1a78b0bd38 [MachineOutliner] Teach outliner to set live-ins
Preserving liveness can be useful even late in the pipeline, if we're
doing substantial optimization work afterwards. (See, for example,
D76065.) Teach MachineOutliner how to correctly set live-ins on the
basic block in outlined functions.

Differential Revision: https://reviews.llvm.org/D78605
2020-04-22 14:19:26 -07:00
Simon Moll 5c8ba508b2 [NFC] unsigned->Register in storeRegTo/loadRegFromStack
Summary:
This patch makes progress on the 'unsigned -> Register' rewrite for
`TargetInstrInfo::loadRegFromStack` and `TII::storeRegToStack`.

Reviewers: arsenm, craig.topper, uweigand, jpienaar, atanasyan, venkatra, robertlytton, dylanmckay, t.p.northover, kparzysz, tstellar, k-ishizaka

Reviewed By: arsenm

Subscribers: wuzish, merge_guards_bot, jyknight, sdardis, nemanjai, jvesely, wdng, nhaehnle, hiraditya, kbarton, fedor.sergeev, asb, rbar, johnrusso, simoncook, sabuasal, niosHD, jrtc27, MaskRay, zzheng, edward-jones, rogfer01, MartinMosbeck, brucehoult, the_o, PkmX, jocewei, jsji, Jim, lenary, s.egerton, pzheng, sameer.abuasal, apazos, luismarques, kerbowa, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D73870
2020-02-03 14:22:16 +01:00
Luís Marques 24cba3312f [RISCV] Implement jump pseudo-instruction
Summary:
Implements the jump pseudo-instruction, which is used in e.g. the Linux kernel.

Reviewers: asb, lenary
Reviewed By: lenary
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D73178
2020-01-31 22:28:26 +00:00
Krzysztof Parzyszek 020041d99b Update spelling of {analyze,insert,remove}Branch in strings and comments
These names have been changed from CamelCase to camelCase, but there were
many places (comments mostly) that still used the old names.

This change is NFC.
2020-01-21 10:15:38 -06:00
Craig Topper caee96031d [Transforms][RISCV] Remove a "using namespace llvm" from an include file. Fix a place that became dependent on it.
This include file was created in October and has a "using namespace llvm". This seems to get exposed to other include files and finally onto cpp files. While this somewhat okay for llvm itself, its bad for other projects that use llvm as a library and includes a header file that picks this up. This was found by ISPC which has some class names at gloal scope with the same names as LLVM.

It looks like RISCV accidentally became dependent on this. I fixed it by reordering some includes in the RISCV code, but maybe we want to change the TableGenEmitter to put "namespace llvm {" in the generated file instead? But we probably want to do the simplest thing first so we can merge it to 10.0.

Differential Revision: https://reviews.llvm.org/D72895
2020-01-16 20:50:41 -08:00
lewis-revill a116f28a0d [RISCV] Enable the machine outliner for RISC-V
This patch enables the machine outliner for RISC-V and adds the
necessary logic for checking whether sequences can be safely outlined,
and describing how they should be outlined. Outlined functions are
called using the register t0 (x5) as the return address register, which
must be available for an occurrence of a sequence to be safely outlined.

Differential Revision: https://reviews.llvm.org/D66210
2019-12-19 16:41:53 +00:00
Kristof Beyls 870f39d310 Fix assertion failure in getMemOperandWithOffsetWidth
This fixes an assertion failure that triggers inside
getMemOperandWithOffset when Machine Sinking calls it on a MachineInstr
that is not a memory operation.

Different backends implement getMemOperandWithOffset differently: some
return false on non-memory MachineInstrs, others assert.

The Machine Sinking pass in at least SinkingPreventsImplicitNullCheck
relies on getMemOperandWithOffset to return false on non-memory
MachineInstrs, instead of asserting.

This patch updates the documentation on getMemOperandWithOffset that it
should return false on any MachineInstr it cannot handle, instead of
asserting. It also adapts the in-tree backends accordingly where
necessary.

Differential Revision: https://reviews.llvm.org/D71359
2019-12-17 10:56:09 +00:00
Ana Pazos d7af86bdd0 [RISCV] Added isCompressibleInst() to estimate size in getInstSizeInBytes()
Summary:
Modified compression emitter tablegen backend to emit isCompressibleInst()
check which in turn is used by getInstSizeInBytes() to better estimate
instruction size. Note the generation of compressed instructions in RISC-V
happens late in the assembler therefore instruction size estimate might be off
if computed before.

Reviewers: lenary, asb, luismarques, lewis-revill

Reviewed By: asb

Subscribers: sameer.abuasal, lewis-revill, hiraditya, asb, rbar, johnrusso, simoncook, sabuasal, niosHD, kito-cheng, shiva0217, MaskRay, zzheng, edward-jones, rogfer01, MartinMosbeck, brucehoult, the_o, rkruppe, PkmX, jocewei, psnobl, benna, Jim, lenary, s.egerton, pzheng, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D68290
2019-12-16 15:15:10 -08:00
Sam Elliott c20930a724 [RISCV] Machine Operand Flag Serialization
Summary:
These hooks ensure that the RISC-V backend can serialize and parse MIR
correctly.

Reviewers: jrtc27, luismarques

Reviewed By: luismarques

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

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D70666
2019-12-09 13:18:32 +00:00
Matt Arsenault e6c9a9af39 Use MCRegister in copyPhysReg 2019-11-11 14:42:33 +05:30
Luís Marques 0d47c7aba3 [RISCV] Add InstrInfo areMemAccessesTriviallyDisjoint hook
Summary: Introduces the `InstrInfo::areMemAccessesTriviallyDisjoint`
hook. The test could check for instruction reorderings, but to avoid
being brittle it just checks instruction dependencies.

Reviewers: asb, lenary
Reviewed By: lenary
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D67046
2019-11-05 09:39:06 +00:00
Luis Marques 1893f9a458 [RISCV] Add MachineInstr immediate verification
Summary:
This patch implements the `TargetInstrInfo::verifyInstruction` hook for RISC-V. Currently the hook verifies the machine instruction's immediate operands, to check if the immediates are within the expected bounds. Without the hook invalid immediates are not detected except when doing assembly parsing, so they are silently emitted (including being truncated when emitting object code).

The bounds information is specified in tablegen by using the `OperandType` definition, which sets the `MCOperandInfo`'s `OperandType` field. Several RISC-V-specific immediate operand types were created, which extend the `MCInstrDesc`'s `OperandType` `enum`.

To have the hook called with `llc` pass it the `-verify-machineinstrs` option. For Clang add the cmake build config `-DLLVM_ENABLE_EXPENSIVE_CHECKS=True`, or temporarily patch `TargetPassConfig::addVerifyPass`.

Review concerns:

- The patch adds immediate operand type checks that cover at least the base ISA. There are several other operand types for the C extension and one type for the F/D extensions that were left out of this initial patch because they introduced further design concerns that I felt were best evaluated separately.

- Invalid register classes (e.g. passing a GPR register where a GPRC is expected) are already caught, so were not included.

- This design makes the more abstract `MachineInstr` verification depend on MC layer definitions, which arguably is not the cleanest design, but is in line with how things are done in other parts of the target and LLVM in general.

- There is some duplication of logic already present in the `MCOperandPredicate`s. Since the `MachineInstr` and `MCInstr` notions of immediates are fundamentally different, this is currently necessary.

Reviewers: asb, lenary

Reviewed By: lenary

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, s.egerton, pzheng, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D67397

llvm-svn: 375006
2019-10-16 15:06:02 +00:00
Shiva Chen a49a16ddd0 [RISCV] Support stack offset exceed 32-bit for RV64
Differential Revision: https://reviews.llvm.org/D61884

llvm-svn: 371810
2019-09-13 04:03:32 +00:00
Shiva Chen ea530ba3ed Revert "[RISCV] Support stack offset exceed 32-bit for RV64"
This reverts commit 1c340c62058d4115d21e5fa1ce3a0d094d28c792.

llvm-svn: 371809
2019-09-13 04:03:24 +00:00
Shiva Chen eaa230fe3c [RISCV] Support stack offset exceed 32-bit for RV64
Differential Revision: https://reviews.llvm.org/D61884

llvm-svn: 371806
2019-09-13 02:50:13 +00:00
Luis Marques fa06e95898 [RISCV] Convert registers from unsigned to Register
Only in public interfaces that have not yet been converted should there remain
registers with unsigned type.

Differential Revision: https://reviews.llvm.org/D66252

llvm-svn: 369114
2019-08-16 14:27:50 +00:00
Daniel Sanders 3836874dbb [risc-v] Apply llvm-prefer-register-over-unsigned from clang-tidy to LLVM
Summary:
This clang-tidy check is looking for unsigned integer variables whose initializer
starts with an implicit cast from llvm::Register and changes the type of the
variable to llvm::Register (dropping the llvm:: where possible).

Depends on D65919

Reviewers: lenary

Subscribers: jholewinski, MatzeB, qcolombet, dschuff, jyknight, dylanmckay, sdardis, nemanjai, jvesely, wdng, nhaehnle, sbc100, jgravelle-google, kristof.beyls, hiraditya, aheejin, kbarton, fedor.sergeev, javed.absar, asb, rbar, johnrusso, simoncook, apazos, sabuasal, niosHD, jrtc27, MaskRay, zzheng, edward-jones, atanasyan, rogfer01, MartinMosbeck, brucehoult, the_o, tpr, PkmX, jocewei, jsji, Petar.Avramovic, asbirlea, Jim, s.egerton, llvm-commits

Tags: #llvm

Differential Revision for full review was: https://reviews.llvm.org/D65962

llvm-svn: 368629
2019-08-12 22:41:02 +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
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
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
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
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
Alex Bradbury 2c6c84e52c [RISCV][NFC] Convert some MachineBaiscBlock::iterator(MI) to MI.getIterator()
llvm-svn: 355864
2019-03-11 20:43:29 +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
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
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
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 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
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
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
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
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
Alex Bradbury 099c720426 Revert "[RISCV] implement li pseudo instruction"
Reverts rL330224, while issues with the C extension and missed common
subexpression elimination opportunities are addressed. Neither of these issues
are visible in current RISC-V backend unit tests, which clearly need
expanding.

llvm-svn: 330281
2018-04-18 19:02:31 +00:00
Alex Bradbury 480b7bc906 [RISCV] implement 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. Additionally,
PseudoLI instructions are emitted during codegen. The actual
expansion to real instructions is performed during MI to MC lowering
and is similar to the expansion performed by the GNU Assembler.

Differential Revision: https://reviews.llvm.org/D41949
Patch by Mario Werner.

llvm-svn: 330224
2018-04-17 21:56:40 +00:00
Alex Bradbury 21d28fe8b8 [RISCV] Codegen support for RV32D floating point comparison operations
Also add double-prevoius-failure.ll which captures a test case that at one
point triggered a compiler crash, while developing calling convention support
for f64 on RV32D with soft-float ABI.

llvm-svn: 329877
2018-04-12 05:50:06 +00:00
Alex Bradbury 0b4175f160 [RISCV] Codegen support for RV32D floating point load/store, fadd.d, calling conv
fadd.d is required in order to force floating point registers to be used in
test code, as parameters are passed in integer registers in the soft float
ABI.

Much of this patch is concerned with support for passing f64 on RV32D with a
soft-float ABI. Similar to Mips, introduce pseudoinstructions to build an f64
out of a pair of i32 and to split an f64 to a pair of i32. BUILD_PAIR and
EXTRACT_ELEMENT can't be used, as a BITCAST to i64 would be necessary, but i64
is not a legal type.

llvm-svn: 329871
2018-04-12 05:34:25 +00:00
Alex Bradbury 65d6ea5e68 [RISCV] Codegen support for RV32F floating point comparison operations
This patch also includes extensive tests targeted at select and br+fcmp IR
inputs. A sequence of br+fcmp required support for FPR32 registers to be added
to RISCVInstrInfo::storeRegToStackSlot and
RISCVInstrInfo::loadRegFromStackSlot.

llvm-svn: 328104
2018-03-21 15:11:02 +00:00
Alex Bradbury 315cd3ace4 [RISCV] Implement support for the BranchRelaxation pass
Branch relaxation is needed to support branch displacements that overflow the
instruction's immediate field.

Differential Revision: https://reviews.llvm.org/D40830

llvm-svn: 322224
2018-01-10 21:05:07 +00:00
Alex Bradbury e027c93ac2 [RISCV] Implement branch analysis
This is a prerequisite for the branch relaxation pass, and allows a number of
optimisation passes (e.g. BranchFolding and MachineBlockPlacement) to work.

Differential Revision: https://reviews.llvm.org/D40808

llvm-svn: 322222
2018-01-10 20:47:00 +00:00
Alex Bradbury 9fea4881d0 [RISCV] Support stack frames and offsets up to 32-bits
Differential Revision: https://reviews.llvm.org/D40807

llvm-svn: 322216
2018-01-10 19:53:46 +00:00
Alex Bradbury 87a54d6110 [RISCV][NFC] Use TargetRegisterClass::hasSubClassEq in storeRegToStackSlot/loadReadFromStackSlot
Simply checking for register class equality will break once additional 
register classes are added (as is done for the RVC instruction set extension).

llvm-svn: 320036
2017-12-07 12:45:05 +00:00
Alex Bradbury a337675cdb [RISCV] Initial support for function calls
Note that this is just enough for simple function call examples to generate 
working code. Support for varargs etc follows in future patches.

Differential Revision: https://reviews.llvm.org/D29936

llvm-svn: 317691
2017-11-08 13:41:21 +00:00
Alex Bradbury 74913e1c70 [RISCV] Codegen for conditional branches
A good portion of this patch is the extra functions that needed to be 
implemented to support the test case. e.g. storeRegToStackSlot, 
loadRegFromStackSlot, eliminateFrameIndex.

Setting ISD::BR_CC to Expand may appear non-obvious on an architecture with 
branch+cmp instructions. However, I found it much easier to deal with matching 
the expanded form.

I had to change simm13_lsb0 and simm21_lsb0 to inherit from the 
Operand<OtherVT> class rather than Operand<i32> in order to keep tablegen 
happy. This isn't a big deal, but it does seem a shame to lose the uniformity 
across immediate types when there's not an obvious benefit (I'm hoping a 
tablegen expert will educate me on what I'm missing here!).

Differential Revision: https://reviews.llvm.org/D29935

llvm-svn: 317690
2017-11-08 13:31:40 +00:00