Commit Graph

105 Commits

Author SHA1 Message Date
Guillaume Chatelet ad1cea0dda [Alignment][NFC] Use Align with TargetLowering::setPrefFunctionAlignment
Summary:
This is patch is part of a series to introduce an Alignment type.
See this thread for context: http://lists.llvm.org/pipermail/llvm-dev/2019-July/133851.html
See this patch for the introduction of the type: https://reviews.llvm.org/D64790

Reviewers: courbet

Subscribers: nemanjai, javed.absar, hiraditya, kbarton, asb, rbar, johnrusso, simoncook, apazos, sabuasal, niosHD, jrtc27, MaskRay, zzheng, edward-jones, rogfer01, MartinMosbeck, brucehoult, the_o, PkmX, jocewei, jsji, s.egerton, pzheng, ychen, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D67267

llvm-svn: 371212
2019-09-06 15:03:49 +00:00
Guillaume Chatelet 4fc3ad9e13 [Alignment][NFC] Use Align with TargetLowering::setMinFunctionAlignment
Summary:
This is patch is part of a series to introduce an Alignment type.
See this thread for context: http://lists.llvm.org/pipermail/llvm-dev/2019-July/133851.html
See this patch for the introduction of the type: https://reviews.llvm.org/D64790

Reviewers: courbet

Subscribers: jyknight, sdardis, nemanjai, javed.absar, hiraditya, kbarton, fedor.sergeev, asb, rbar, johnrusso, simoncook, apazos, sabuasal, niosHD, jrtc27, MaskRay, zzheng, edward-jones, atanasyan, rogfer01, MartinMosbeck, brucehoult, the_o, PkmX, jocewei, jsji, s.egerton, pzheng, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D67229

llvm-svn: 371200
2019-09-06 12:48:34 +00:00
Guillaume Chatelet aff45e4b23 [LLVM][Alignment] Make functions using log of alignment explicit
Summary:
This patch renames functions that takes or returns alignment as log2, this patch will help with the transition to llvm::Align.
The renaming makes it explicit that we deal with log(alignment) instead of a power of two alignment.
A few renames uncovered dubious assignments:

 - `MirParser`/`MirPrinter` was expecting powers of two but `MachineFunction` and `MachineBasicBlock` were using deal with log2(align). This patch fixes it and updates the documentation.
 - `MachineBlockPlacement` exposes two flags (`align-all-blocks` and `align-all-nofallthru-blocks`) supposedly interpreted as power of two alignments, internally these values are interpreted as log2(align). This patch updates the documentation,
 - `MachineFunctionexposes` exposes `align-all-functions` also interpreted as power of two alignment, internally this value is interpreted as log2(align). This patch updates the documentation,

Reviewers: lattner, thegameg, courbet

Subscribers: dschuff, arsenm, jyknight, dylanmckay, sdardis, nemanjai, jvesely, nhaehnle, javed.absar, hiraditya, kbarton, fedor.sergeev, asb, rbar, johnrusso, simoncook, apazos, sabuasal, niosHD, jrtc27, MaskRay, zzheng, edward-jones, atanasyan, rogfer01, MartinMosbeck, brucehoult, the_o, dexonsmith, PkmX, jocewei, jsji, Jim, s.egerton, llvm-commits, courbet

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D65945

llvm-svn: 371045
2019-09-05 10:00:22 +00:00
Jim Lin b77aa1d248 [RISCV] Enable tail call opt for variadic function
Summary: Tail call opt can treat variadic function call the same as normal function call

Reviewers: mgrang, asb, lenary, lewis-revill

Reviewed By: lenary

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

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D66278

llvm-svn: 370835
2019-09-04 02:03:36 +00:00
Shiva Chen b39876d8cd [RISCV] Avoid generating AssertZext for LP64 ABI when lowering floating LibCall
The patch fixed the issue that RV64 didn't clear the upper bits
when return complex floating value with lp64 ABI.

float _Complex
complex_add(float _Complex a, float _Complex b)
{
   return a + b;
}

RealResult = zero_extend(RealA + RealB)
ImageResult = ImageA + ImageB
Return (RealResult | (ImageResult << 32))

The patch introduces shouldExtendTypeInLibCall target hook to suppress
the AssertZext generation when lowering floating LibCall.

Thanks to Eli's comments from the Bugzilla
https://bugs.llvm.org/show_bug.cgi?id=42820

Differential Revision: https://reviews.llvm.org/D65497

llvm-svn: 370275
2019-08-28 23:40:37 +00:00
Benjamin Kramer dc5f805d31 Do a sweep of symbol internalization. NFC.
llvm-svn: 369803
2019-08-23 19:59:23 +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
Lewis Revill 7abf863f76 [RISCV] Lower inline asm constraint A for RISC-V
This allows arguments with the constraint A to be lowered to input nodes
for RISC-V, which implies a memory address stored in a register.

This patch adds the minimal amount of code required to get operands with
the right constraints to compile.

https://reviews.llvm.org/D54296

llvm-svn: 369095
2019-08-16 10:28:34 +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
Sam Elliott fee242aed4 [RISCV] Fix ICE in isDesirableToCommuteWithShift
Summary:
Ana Pazos reported a bug where we were not checking that an APInt would
fit into 64-bits before calling `getSExtValue()`. This caused asserts when
compiling large constants, such as i128s, as happens when compiling compiler-rt.

This patch adds a testcase and makes the callback less error-prone.

Reviewers: apazos, asb, luismarques

Reviewed By: luismarques

Subscribers: hiraditya, 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, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D66081

llvm-svn: 368572
2019-08-12 13:51:00 +00:00
Sam Elliott 856d5c5817 [RISCV] Allow ABI Names in Inline Assembly Constraints
Summary:
Clang will replace references to registers using ABI names in inline
assembly constraints with references to architecture names, but other
frontends do not. LLVM uses the regular assembly parser to parse inline asm,
so inline assembly strings can contain references to registers using their
ABI names.

This patch adds support for parsing constraints using either the ABI name or
the architectural register name. This means we do not need to implement the
ABI name replacement code in every single frontend, especially those like
Rust which are a very thin shim on top of LLVM IR's inline asm, and that
constraints can more closely match the assembly strings they refer to.

Reviewers: asb, simoncook

Reviewed By: simoncook

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

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D65947

llvm-svn: 368303
2019-08-08 14:59:16 +00:00
Shiva Chen b12056bd33 [RISCV] Custom legalize i32 operations for RV64 to reduce signed extensions
Differential Revision: https://reviews.llvm.org/D65434

llvm-svn: 367960
2019-08-06 00:24:00 +00:00
Guillaume Chatelet c97a3d15d2 [LLVM][Alignment] Introduce Alignment Type
Summary:
This is patch is part of a serie to introduce an Alignment type.
See this thread for context: http://lists.llvm.org/pipermail/llvm-dev/2019-July/133851.html
See this patch for the introduction of the type: https://reviews.llvm.org/D64790

Reviewers: courbet, jfb, jakehehrlich

Reviewed By: jfb

Subscribers: wuzish, jholewinski, arsenm, dschuff, nemanjai, jvesely, nhaehnle, javed.absar, sbc100, jgravelle-google, hiraditya, aheejin, kbarton, asb, rbar, johnrusso, simoncook, apazos, sabuasal, niosHD, jrtc27, MaskRay, zzheng, edward-jones, rogfer01, MartinMosbeck, brucehoult, the_o, dexonsmith, PkmX, jocewei, jsji, s.egerton, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D65514

llvm-svn: 367828
2019-08-05 11:02:05 +00:00
Bill Wendling 41a2847a9a Emit diagnostic if an inline asm constraint requires an immediate
Summary:
An inline asm call can result in an immediate after inlining. Therefore emit a
diagnostic here if constraint requires an immediate but one isn't supplied.

Reviewers: joerg, mgorny, efriedma, rsmith

Reviewed By: joerg

Subscribers: asb, rbar, johnrusso, simoncook, apazos, sabuasal, niosHD, zzheng, edward-jones, rogfer01, MartinMosbeck, brucehoult, the_o, PkmX, jocewei, s.egerton, MaskRay, jyknight, dylanmckay, javed.absar, fedor.sergeev, jrtc27, Jim, krytarowski, eraman, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D60942

llvm-svn: 367750
2019-08-03 05:52:47 +00:00
Sam Elliott 9e6b2e1605 [RISCV] Support 'f' Inline Assembly Constraint
Summary:
This adds the 'f' inline assembly constraint, as supported by GCC. An
'f'-constrained operand is passed in a floating point register. Exactly
which kind of floating-point register (32-bit or 64-bit) is decided
based on the operand type and the available standard extensions (-f and
-d, respectively).

This patch adds support in both the clang frontend, and LLVM itself.

Reviewers: asb, lewis-revill

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, s.egerton, cfe-commits, llvm-commits

Tags: #clang, #llvm

Differential Revision: https://reviews.llvm.org/D65500

llvm-svn: 367403
2019-07-31 09:45:55 +00:00
Simon Cook 8d7ec4d644 [RISCV] Add support for lowering floating point inlineasm clobbers
This adds the required extension to RISC-V's getRegForInlineAsmConstraint
in order to be able to correctly distringuish between the 32 and 64-bit
floating point registers when the generic fX name appears in inlineasm
clobber contraints. It also adds a check to validate that callee saved
floating point registers are only saved in this case when a hard-float
ABI is selected.

Differential Revision: https://reviews.llvm.org/D64751

llvm-svn: 367397
2019-07-31 09:07:21 +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
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 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
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
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
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
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
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
Lewis Revill 24a74096a4 Test commit: Remove double variable assignment
llvm-svn: 357601
2019-04-03 15:54:30 +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 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
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 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
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 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
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
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
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 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 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