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llvm-project/llvm/lib/Target/RISCV/RISCVISelLowering.h

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[RISCV] Initial codegen support for ALU operations This adds the minimum necessary to support codegen for simple ALU operations on RV32. Prolog and epilog insertion, support for memory operations etc etc follow in future patches. Leave guessInstructionProperties=1 until https://reviews.llvm.org/D37065 is reviewed and lands. Differential Revision: https://reviews.llvm.org/D29933 llvm-svn: 316188
2017-10-20 05:37:38 +08:00
//===-- RISCVISelLowering.h - RISCV DAG Lowering Interface ------*- C++ -*-===//
//
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 16:50:56 +08:00
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
[RISCV] Initial codegen support for ALU operations This adds the minimum necessary to support codegen for simple ALU operations on RV32. Prolog and epilog insertion, support for memory operations etc etc follow in future patches. Leave guessInstructionProperties=1 until https://reviews.llvm.org/D37065 is reviewed and lands. Differential Revision: https://reviews.llvm.org/D29933 llvm-svn: 316188
2017-10-20 05:37:38 +08:00
//
//===----------------------------------------------------------------------===//
//
// This file defines the interfaces that RISCV uses to lower LLVM code into a
// selection DAG.
//
//===----------------------------------------------------------------------===//
#ifndef LLVM_LIB_TARGET_RISCV_RISCVISELLOWERING_H
#define LLVM_LIB_TARGET_RISCV_RISCVISELLOWERING_H
#include "RISCV.h"
#include "llvm/CodeGen/SelectionDAG.h"
Fix a bunch more layering of CodeGen headers that are in Target All these headers already depend on CodeGen headers so moving them into CodeGen fixes the layering (since CodeGen depends on Target, not the other way around). llvm-svn: 318490
2017-11-17 09:07:10 +08:00
#include "llvm/CodeGen/TargetLowering.h"
[RISCV] Initial codegen support for ALU operations This adds the minimum necessary to support codegen for simple ALU operations on RV32. Prolog and epilog insertion, support for memory operations etc etc follow in future patches. Leave guessInstructionProperties=1 until https://reviews.llvm.org/D37065 is reviewed and lands. Differential Revision: https://reviews.llvm.org/D29933 llvm-svn: 316188
2017-10-20 05:37:38 +08:00
namespace llvm {
class RISCVSubtarget;
namespace RISCVISD {
enum NodeType : unsigned {
FIRST_NUMBER = ISD::BUILTIN_OP_END,
[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 21:41:21 +08:00
RET_FLAG,
[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
2018-07-27 01:49:43 +08:00
URET_FLAG,
SRET_FLAG,
MRET_FLAG,
[RISCV] Implement lowering of ISD::SELECT Although ISD::SELECT_CC is a more natural match for RISCVISD::SELECT_CC (and ultimately the integer RISC-V conditional branch instructions), we choose to expand ISD::SELECT_CC and lower ISD::SELECT. The appropriate compare+branch will be created in the case where an ISD::SELECT condition value is created by an ISD::SETCC node, which operates on XLen types. Other datatypes such as floating point don't have conditional branch instructions, and lowering ISD::SELECT allows more flexibility for handling these cases. Differential Revision: https://reviews.llvm.org/D29937 llvm-svn: 318735
2017-11-21 15:51:32 +08:00
CALL,
[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 13:34:25 +08:00
SELECT_CC,
BuildPairF64,
[RISCV] Lower the tail pseudoinstruction This patch lowers the tail pseudoinstruction. This has been modeled after ARM's tail call opt. llvm-svn: 333137
2018-05-24 06:44:08 +08:00
SplitF64,
[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 13:04:00 +08:00
TAIL,
// RV64I shifts, directly matching the semantics of the named RISC-V
// instructions.
SLLW,
SRAW,
[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 13:11:34 +08:00
SRLW,
// 32-bit operations from RV64M that can't be simply matched with a pattern
// at instruction selection time.
DIVW,
DIVUW,
[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
2019-02-01 06:48:38 +08:00
REMUW,
// FPR32<->GPR transfer operations for RV64. Needed as an i32<->f32 bitcast
// is not legal on RV64. FMV_W_X_RV64 matches the semantics of the FMV.W.X.
// FMV_X_ANYEXTW_RV64 is similar to FMV.X.W but has an any-extended result.
// This is a more convenient semantic for producing dagcombines that remove
// unnecessary GPR->FPR->GPR moves.
FMV_W_X_RV64,
[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 20:35:21 +08:00
FMV_X_ANYEXTW_RV64,
// READ_CYCLE_WIDE - A read of the 64-bit cycle CSR on a 32-bit target
// (returns (Lo, Hi)). It takes a chain operand.
READ_CYCLE_WIDE
[RISCV] Initial codegen support for ALU operations This adds the minimum necessary to support codegen for simple ALU operations on RV32. Prolog and epilog insertion, support for memory operations etc etc follow in future patches. Leave guessInstructionProperties=1 until https://reviews.llvm.org/D37065 is reviewed and lands. Differential Revision: https://reviews.llvm.org/D29933 llvm-svn: 316188
2017-10-20 05:37:38 +08:00
};
}
class RISCVTargetLowering : public TargetLowering {
const RISCVSubtarget &Subtarget;
public:
explicit RISCVTargetLowering(const TargetMachine &TM,
const RISCVSubtarget &STI);
[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 18:54:22 +08:00
bool getTgtMemIntrinsic(IntrinsicInfo &Info, const CallInst &I,
MachineFunction &MF,
unsigned Intrinsic) const override;
[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 20:13:48 +08:00
bool isLegalAddressingMode(const DataLayout &DL, const AddrMode &AM, Type *Ty,
unsigned AS,
Instruction *I = nullptr) const override;
[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 21:15:17 +08:00
bool isLegalICmpImmediate(int64_t Imm) const override;
[RISCV] Implement isLegalAddImmediate This causes a trivial improvement in the recently added lsr-legaladdimm.ll test case. llvm-svn: 330937
2018-04-26 21:00:37 +08:00
bool isLegalAddImmediate(int64_t Imm) const override;
[RISCV] Implement isTruncateFree Adapted from ARM's implementation introduced in r313533 and r314280. llvm-svn: 330940
2018-04-26 21:37:00 +08:00
bool isTruncateFree(Type *SrcTy, Type *DstTy) const override;
bool isTruncateFree(EVT SrcVT, EVT DstVT) const override;
[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 22:04:18 +08:00
bool isZExtFree(SDValue Val, EVT VT2) const override;
[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 17:56:54 +08:00
bool isSExtCheaperThanZExt(EVT SrcVT, EVT DstVT) const override;
[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 20:20:14 +08:00
bool hasBitPreservingFPLogic(EVT VT) const override;
[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 20:13:48 +08:00
[RISCV] Initial codegen support for ALU operations This adds the minimum necessary to support codegen for simple ALU operations on RV32. Prolog and epilog insertion, support for memory operations etc etc follow in future patches. Leave guessInstructionProperties=1 until https://reviews.llvm.org/D37065 is reviewed and lands. Differential Revision: https://reviews.llvm.org/D29933 llvm-svn: 316188
2017-10-20 05:37:38 +08:00
// Provide custom lowering hooks for some operations.
SDValue LowerOperation(SDValue Op, SelectionDAG &DAG) const override;
[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 13:04:00 +08:00
void ReplaceNodeResults(SDNode *N, SmallVectorImpl<SDValue> &Results,
SelectionDAG &DAG) const override;
[RISCV] Initial codegen support for ALU operations This adds the minimum necessary to support codegen for simple ALU operations on RV32. Prolog and epilog insertion, support for memory operations etc etc follow in future patches. Leave guessInstructionProperties=1 until https://reviews.llvm.org/D37065 is reviewed and lands. Differential Revision: https://reviews.llvm.org/D29933 llvm-svn: 316188
2017-10-20 05:37:38 +08:00
[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
2018-10-04 07:30:16 +08:00
SDValue PerformDAGCombine(SDNode *N, DAGCombinerInfo &DCI) const override;
[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 13:04:00 +08:00
unsigned ComputeNumSignBitsForTargetNode(SDValue Op,
const APInt &DemandedElts,
const SelectionDAG &DAG,
unsigned Depth) const override;
[RISCV] Initial codegen support for ALU operations This adds the minimum necessary to support codegen for simple ALU operations on RV32. Prolog and epilog insertion, support for memory operations etc etc follow in future patches. Leave guessInstructionProperties=1 until https://reviews.llvm.org/D37065 is reviewed and lands. Differential Revision: https://reviews.llvm.org/D29933 llvm-svn: 316188
2017-10-20 05:37:38 +08:00
// This method returns the name of a target specific DAG node.
const char *getTargetNodeName(unsigned Opcode) const override;
[RISCV] Add basic support for inline asm constraints llvm-svn: 322217
2018-01-11 04:05:09 +08:00
[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 17:45:55 +08:00
ConstraintType getConstraintType(StringRef Constraint) const override;
[RISCV] Add basic support for inline asm constraints llvm-svn: 322217
2018-01-11 04:05:09 +08:00
std::pair<unsigned, const TargetRegisterClass *>
getRegForInlineAsmConstraint(const TargetRegisterInfo *TRI,
StringRef Constraint, MVT VT) const override;
[RISCV] Initial codegen support for ALU operations This adds the minimum necessary to support codegen for simple ALU operations on RV32. Prolog and epilog insertion, support for memory operations etc etc follow in future patches. Leave guessInstructionProperties=1 until https://reviews.llvm.org/D37065 is reviewed and lands. Differential Revision: https://reviews.llvm.org/D29933 llvm-svn: 316188
2017-10-20 05:37:38 +08:00
[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 20:42:13 +08:00
void LowerAsmOperandForConstraint(SDValue Op, std::string &Constraint,
std::vector<SDValue> &Ops,
SelectionDAG &DAG) const override;
[RISCV] Implement lowering of ISD::SELECT Although ISD::SELECT_CC is a more natural match for RISCVISD::SELECT_CC (and ultimately the integer RISC-V conditional branch instructions), we choose to expand ISD::SELECT_CC and lower ISD::SELECT. The appropriate compare+branch will be created in the case where an ISD::SELECT condition value is created by an ISD::SETCC node, which operates on XLen types. Other datatypes such as floating point don't have conditional branch instructions, and lowering ISD::SELECT allows more flexibility for handling these cases. Differential Revision: https://reviews.llvm.org/D29937 llvm-svn: 318735
2017-11-21 15:51:32 +08:00
MachineBasicBlock *
EmitInstrWithCustomInserter(MachineInstr &MI,
MachineBasicBlock *BB) const override;
[RISCV] Define getSetCCResultType for setting vector setCC type To avoid trigger "No default SetCC type for vectors!" Assertion Differential Revision: https://reviews.llvm.org/D42675 llvm-svn: 324054
2018-02-02 10:43:18 +08:00
EVT getSetCCResultType(const DataLayout &DL, LLVMContext &Context,
EVT VT) const override;
[RISCV] Implement lowering of ISD::SELECT Although ISD::SELECT_CC is a more natural match for RISCVISD::SELECT_CC (and ultimately the integer RISC-V conditional branch instructions), we choose to expand ISD::SELECT_CC and lower ISD::SELECT. The appropriate compare+branch will be created in the case where an ISD::SELECT condition value is created by an ISD::SETCC node, which operates on XLen types. Other datatypes such as floating point don't have conditional branch instructions, and lowering ISD::SELECT allows more flexibility for handling these cases. Differential Revision: https://reviews.llvm.org/D29937 llvm-svn: 318735
2017-11-21 15:51:32 +08:00
[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 18:39:22 +08:00
bool convertSetCCLogicToBitwiseLogic(EVT VT) const override {
return VT.isScalarInteger();
}
[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 20:04:51 +08:00
bool shouldInsertFencesForAtomic(const Instruction *I) const override {
return isa<LoadInst>(I) || isa<StoreInst>(I);
}
Instruction *emitLeadingFence(IRBuilder<> &Builder, Instruction *Inst,
AtomicOrdering Ord) const override;
Instruction *emitTrailingFence(IRBuilder<> &Builder, Instruction *Inst,
AtomicOrdering Ord) const override;
[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
2019-03-12 05:41:22 +08:00
ISD::NodeType getExtendForAtomicOps() const override {
return ISD::SIGN_EXTEND;
}
[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 22:38:32 +08:00
bool shouldExpandShift(SelectionDAG &DAG, SDNode *N) const override {
if (DAG.getMachineFunction().getFunction().hasMinSize())
return false;
return true;
}
[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
2019-06-19 04:38:08 +08:00
bool isDesirableToCommuteWithShift(const SDNode *N,
CombineLevel Level) const override;
[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 22:38:32 +08:00
[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 17:16:47 +08:00
/// If a physical register, this returns the register that receives the
/// exception address on entry to an EH pad.
unsigned
getExceptionPointerRegister(const Constant *PersonalityFn) const override;
/// If a physical register, this returns the register that receives the
/// exception typeid on entry to a landing pad.
unsigned
getExceptionSelectorRegister(const Constant *PersonalityFn) const override;
[RISCV] Initial codegen support for ALU operations This adds the minimum necessary to support codegen for simple ALU operations on RV32. Prolog and epilog insertion, support for memory operations etc etc follow in future patches. Leave guessInstructionProperties=1 until https://reviews.llvm.org/D37065 is reviewed and lands. Differential Revision: https://reviews.llvm.org/D29933 llvm-svn: 316188
2017-10-20 05:37:38 +08:00
private:
[RISCV] Add custom CC_RISCV calling convention and improved call support The TableGen-based calling convention definitions are inflexible, while writing a function to implement the calling convention is very straight-forward, and allows difficult cases to be handled more easily. With this patch adds support for: * Passing large scalars according to the RV32I calling convention * Byval arguments * Passing values on the stack when the argument registers are exhausted The custom CC_RISCV calling convention is also used for returns. This patch also documents the ABI lowering that a language frontend is expected to perform. I would like to work to simplify these requirements over time, but this will require further discussion within the LLVM community. We add PendingArgFlags CCState, as a companion to PendingLocs. The PendingLocs vector is used by a number of backends to handle arguments that are split during legalisation. However CCValAssign doesn't keep track of the original argument alignment. Therefore, add a PendingArgFlags vector which can be used to keep track of the ISD::ArgFlagsTy for every value added to PendingLocs. Differential Revision: https://reviews.llvm.org/D39898 llvm-svn: 320359
2017-12-11 20:49:02 +08:00
void analyzeInputArgs(MachineFunction &MF, CCState &CCInfo,
const SmallVectorImpl<ISD::InputArg> &Ins,
bool IsRet) const;
void analyzeOutputArgs(MachineFunction &MF, CCState &CCInfo,
const SmallVectorImpl<ISD::OutputArg> &Outs,
[RISCV] Support for varargs Includes support for expanding va_copy. Also adds support for using 'aligned' registers when necessary for vararg calls, and ensure the frame pointer always points to the bottom of the vararg spill region. This is necessary to ensure that the saved return address and stack pointer are always available at fixed known offsets of the frame pointer. Differential Revision: https://reviews.llvm.org/D40805 llvm-svn: 322215
2018-01-11 03:41:03 +08:00
bool IsRet, CallLoweringInfo *CLI) const;
[RISCV] Initial codegen support for ALU operations This adds the minimum necessary to support codegen for simple ALU operations on RV32. Prolog and epilog insertion, support for memory operations etc etc follow in future patches. Leave guessInstructionProperties=1 until https://reviews.llvm.org/D37065 is reviewed and lands. Differential Revision: https://reviews.llvm.org/D29933 llvm-svn: 316188
2017-10-20 05:37:38 +08:00
// Lower incoming arguments, copy physregs into vregs
SDValue LowerFormalArguments(SDValue Chain, CallingConv::ID CallConv,
bool IsVarArg,
const SmallVectorImpl<ISD::InputArg> &Ins,
const SDLoc &DL, SelectionDAG &DAG,
SmallVectorImpl<SDValue> &InVals) const override;
[RISCV] Add custom CC_RISCV calling convention and improved call support The TableGen-based calling convention definitions are inflexible, while writing a function to implement the calling convention is very straight-forward, and allows difficult cases to be handled more easily. With this patch adds support for: * Passing large scalars according to the RV32I calling convention * Byval arguments * Passing values on the stack when the argument registers are exhausted The custom CC_RISCV calling convention is also used for returns. This patch also documents the ABI lowering that a language frontend is expected to perform. I would like to work to simplify these requirements over time, but this will require further discussion within the LLVM community. We add PendingArgFlags CCState, as a companion to PendingLocs. The PendingLocs vector is used by a number of backends to handle arguments that are split during legalisation. However CCValAssign doesn't keep track of the original argument alignment. Therefore, add a PendingArgFlags vector which can be used to keep track of the ISD::ArgFlagsTy for every value added to PendingLocs. Differential Revision: https://reviews.llvm.org/D39898 llvm-svn: 320359
2017-12-11 20:49:02 +08:00
bool CanLowerReturn(CallingConv::ID CallConv, MachineFunction &MF,
bool IsVarArg,
const SmallVectorImpl<ISD::OutputArg> &Outs,
LLVMContext &Context) const override;
[RISCV] Initial codegen support for ALU operations This adds the minimum necessary to support codegen for simple ALU operations on RV32. Prolog and epilog insertion, support for memory operations etc etc follow in future patches. Leave guessInstructionProperties=1 until https://reviews.llvm.org/D37065 is reviewed and lands. Differential Revision: https://reviews.llvm.org/D29933 llvm-svn: 316188
2017-10-20 05:37:38 +08:00
SDValue LowerReturn(SDValue Chain, CallingConv::ID CallConv, bool IsVarArg,
const SmallVectorImpl<ISD::OutputArg> &Outs,
const SmallVectorImpl<SDValue> &OutVals, const SDLoc &DL,
SelectionDAG &DAG) const override;
[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 21:41:21 +08:00
SDValue LowerCall(TargetLowering::CallLoweringInfo &CLI,
SmallVectorImpl<SDValue> &InVals) const override;
[RISCV] Initial codegen support for ALU operations This adds the minimum necessary to support codegen for simple ALU operations on RV32. Prolog and epilog insertion, support for memory operations etc etc follow in future patches. Leave guessInstructionProperties=1 until https://reviews.llvm.org/D37065 is reviewed and lands. Differential Revision: https://reviews.llvm.org/D29933 llvm-svn: 316188
2017-10-20 05:37:38 +08:00
bool shouldConvertConstantLoadToIntImm(const APInt &Imm,
Type *Ty) const override {
return true;
}
[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 22:42:56 +08:00
template <class NodeTy>
[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 20:57:47 +08:00
SDValue getAddr(NodeTy *N, SelectionDAG &DAG, bool IsLocal = true) const;
[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 22:42:56 +08:00
[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 16:40:59 +08:00
SDValue getStaticTLSAddr(GlobalAddressSDNode *N, SelectionDAG &DAG,
bool UseGOT) const;
SDValue getDynamicTLSAddr(GlobalAddressSDNode *N, SelectionDAG &DAG) const;
[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 18:54:12 +08:00
bool shouldConsiderGEPOffsetSplit() const override { return true; }
[RISCV] Codegen support for memory operations on global addresses Differential Revision: https://reviews.llvm.org/D39103 llvm-svn: 317688
2017-11-08 21:24:21 +08:00
SDValue lowerGlobalAddress(SDValue Op, SelectionDAG &DAG) const;
[RISCV] Support and tests for a variety of additional LLVM IR constructs Previous patches primarily ensured that codegen was possible for the standard RISC-V instructions. However, there are a number of IR inputs that wouldn't be appropriately lowered. This patch both adds test cases and supports lowering for a number of these cases: * Improved sext/zext/trunc support * Support for setcc variants that don't map directly to RISC-V instructions * Lowering mul, and hence support for external symbols * addc, adde, subc, sube * mulhs, srem, mulhu, urem, udiv, sdiv * {srl,sra,shl}_parts * brind * br_jt * bswap, ctlz, cttz, ctpop * rotl, rotr * BlockAddress operands Differential Revision: https://reviews.llvm.org/D29938 llvm-svn: 318737
2017-11-21 16:11:03 +08:00
SDValue lowerBlockAddress(SDValue Op, SelectionDAG &DAG) const;
[RISCV] Add codegen for RV32F floating point load/store As part of this, add support for load/store from the constant pool. This is used to materialise f32 constants. llvm-svn: 327979
2018-03-20 21:26:12 +08:00
SDValue lowerConstantPool(SDValue Op, SelectionDAG &DAG) const;
[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 16:40:59 +08:00
SDValue lowerGlobalTLSAddress(SDValue Op, SelectionDAG &DAG) const;
[RISCV] Implement lowering of ISD::SELECT Although ISD::SELECT_CC is a more natural match for RISCVISD::SELECT_CC (and ultimately the integer RISC-V conditional branch instructions), we choose to expand ISD::SELECT_CC and lower ISD::SELECT. The appropriate compare+branch will be created in the case where an ISD::SELECT condition value is created by an ISD::SETCC node, which operates on XLen types. Other datatypes such as floating point don't have conditional branch instructions, and lowering ISD::SELECT allows more flexibility for handling these cases. Differential Revision: https://reviews.llvm.org/D29937 llvm-svn: 318735
2017-11-21 15:51:32 +08:00
SDValue lowerSELECT(SDValue Op, SelectionDAG &DAG) const;
[RISCV] Support for varargs Includes support for expanding va_copy. Also adds support for using 'aligned' registers when necessary for vararg calls, and ensure the frame pointer always points to the bottom of the vararg spill region. This is necessary to ensure that the saved return address and stack pointer are always available at fixed known offsets of the frame pointer. Differential Revision: https://reviews.llvm.org/D40805 llvm-svn: 322215
2018-01-11 03:41:03 +08:00
SDValue lowerVASTART(SDValue Op, SelectionDAG &DAG) const;
[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 13:27:50 +08:00
SDValue lowerFRAMEADDR(SDValue Op, SelectionDAG &DAG) const;
SDValue lowerRETURNADDR(SDValue Op, SelectionDAG &DAG) const;
[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 22:38:32 +08:00
SDValue lowerShiftLeftParts(SDValue Op, SelectionDAG &DAG) const;
SDValue lowerShiftRightParts(SDValue Op, SelectionDAG &DAG, bool IsSRA) const;
[RISCV] Lower the tail pseudoinstruction This patch lowers the tail pseudoinstruction. This has been modeled after ARM's tail call opt. llvm-svn: 333137
2018-05-24 06:44:08 +08:00
[RISCV][NFC] IsEligibleForTailCallOptimization -> isEligibleForTailCallOptimization Also clang-format the modified hunks. llvm-svn: 354584
2019-02-21 22:31:41 +08:00
bool isEligibleForTailCallOptimization(
CCState &CCInfo, CallLoweringInfo &CLI, MachineFunction &MF,
const SmallVector<CCValAssign, 16> &ArgLocs) const;
[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 18:54:22 +08:00
TargetLowering::AtomicExpansionKind
shouldExpandAtomicRMWInIR(AtomicRMWInst *AI) const override;
virtual Value *emitMaskedAtomicRMWIntrinsic(
IRBuilder<> &Builder, AtomicRMWInst *AI, Value *AlignedAddr, Value *Incr,
Value *Mask, Value *ShiftAmt, AtomicOrdering Ord) const override;
[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
2018-11-30 04:43:42 +08:00
TargetLowering::AtomicExpansionKind
shouldExpandAtomicCmpXchgInIR(AtomicCmpXchgInst *CI) const override;
virtual Value *
emitMaskedAtomicCmpXchgIntrinsic(IRBuilder<> &Builder, AtomicCmpXchgInst *CI,
Value *AlignedAddr, Value *CmpVal,
Value *NewVal, Value *Mask,
AtomicOrdering Ord) const override;
[RISCV] Initial codegen support for ALU operations This adds the minimum necessary to support codegen for simple ALU operations on RV32. Prolog and epilog insertion, support for memory operations etc etc follow in future patches. Leave guessInstructionProperties=1 until https://reviews.llvm.org/D37065 is reviewed and lands. Differential Revision: https://reviews.llvm.org/D29933 llvm-svn: 316188
2017-10-20 05:37:38 +08:00
};
}
#endif