[RISCV][MC] Add MC support of Zibi experimental extension

clang/test/Driver/print-supported-extensions-riscv.c

@@ -211,6 +211,7 @@
 // CHECK-EMPTY:
 // CHECK-NEXT: Experimental extensions
 // CHECK-NEXT:     p                    0.15      'P' ('Base P' (Packed SIMD))
+// CHECK-NEXT:     zibi                 0.1       'Zibi' (Branch with Immediate)
 // CHECK-NEXT:     zicfilp              1.0       'Zicfilp' (Landing pad)
 // CHECK-NEXT:     zicfiss              1.0       'Zicfiss' (Shadow stack)
 // CHECK-NEXT:     zalasr               0.1       'Zalasr' (Load-Acquire and Store-Release Instructions)

clang/test/Preprocessor/riscv-target-features.c

@@ -96,6 +96,7 @@
 // CHECK-NOT: __riscv_zfinx {{.*$}}
 // CHECK-NOT: __riscv_zhinx {{.*$}}
 // CHECK-NOT: __riscv_zhinxmin {{.*$}}
+// CHECK-NOT: __riscv_zibi {{.*$}}
 // CHECK-NOT: __riscv_zic64b {{.*$}}
 // CHECK-NOT: __riscv_zicbom {{.*$}}
 // CHECK-NOT: __riscv_zicbop {{.*$}}
@@ -812,6 +813,14 @@
 // RUN:   -o - | FileCheck --check-prefix=CHECK-ZHINXMIN-EXT %s
 // CHECK-ZHINXMIN-EXT: __riscv_zhinxmin 1000000{{$}}
 
+// RUN: %clang --target=riscv32 -menable-experimental-extensions \
+// RUN:   -march=rv32i_zibi0p1 -E -dM %s \
+// RUN:   -o - | FileCheck --check-prefix=CHECK-ZIBI-EXT %s
+// RUN: %clang --target=riscv64 -menable-experimental-extensions \
+// RUN:   -march=rv64i_zibi0p1 -E -dM %s \
+// RUN:   -o - | FileCheck --check-prefix=CHECK-ZIBI-EXT %s
+// CHECK-ZIBI-EXT: __riscv_zibi
+
 // RUN: %clang --target=riscv32-unknown-linux-gnu \
 // RUN:   -march=rv32izic64b -E -dM %s \
 // RUN:   -o - | FileCheck --check-prefix=CHECK-ZIC64B-EXT %s

llvm/docs/RISCVUsage.rst

@@ -327,6 +327,9 @@ The primary goal of experimental support is to assist in the process of ratifica
 ``experimental-zalasr``
   LLVM implements the `0.0.5 draft specification <https://github.com/mehnadnerd/riscv-zalasr>`__.
 
+``experimental-zibi``
+  LLVM implements the `0.1 release specification <https://lf-riscv.atlassian.net/wiki/spaces/USXX/pages/599261201/Branch+with+Immediate+Zibi+Ratification+Plan>`__.
+
 ``experimental-zicfilp``, ``experimental-zicfiss``
   LLVM implements the `1.0 release specification <https://github.com/riscv/riscv-cfi/releases/tag/v1.0>`__.
 

llvm/docs/ReleaseNotes.md

@@ -120,6 +120,7 @@ Changes to the RISC-V Backend
   using `$x` with an architecture string suffix is not yet supported.
 * Ssctr and Smctr extensions are no longer experimental.
 * Add support for Zvfbfa (Additional BF16 vector compute support)
+* Adds experimental support for the 'Zibi` (Branch with Immediate) extension.
 
 Changes to the WebAssembly Backend
 ----------------------------------

llvm/lib/Target/RISCV/AsmParser/RISCVAsmParser.cpp

@@ -745,6 +745,11 @@ struct RISCVOperand final : public MCParsedAsmOperand {
     return isUImmPred([](int64_t Imm) { return Imm != 0 && isUInt<5>(Imm); });
   }
 
+  bool isUImm5Zibi() const {
+    return isUImmPred(
+        [](int64_t Imm) { return (Imm != 0 && isUInt<5>(Imm)) || Imm == -1; });
+  }
+
   bool isUImm5GT3() const {
     return isUImmPred([](int64_t Imm) { return isUInt<5>(Imm) && Imm > 3; });
   }
@@ -1488,6 +1493,10 @@ bool RISCVAsmParser::matchAndEmitInstruction(SMLoc IDLoc, unsigned &Opcode,
     return generateImmOutOfRangeError(Operands, ErrorInfo, 0, (1 << 5) - 1);
   case Match_InvalidUImm5NonZero:
     return generateImmOutOfRangeError(Operands, ErrorInfo, 1, (1 << 5) - 1);
+  case Match_InvalidUImm5Zibi:
+    return generateImmOutOfRangeError(
+        Operands, ErrorInfo, -1, (1 << 5) - 1,
+        "immediate must be non-zero in the range");
   case Match_InvalidUImm5GT3:
     return generateImmOutOfRangeError(Operands, ErrorInfo, 4, (1 << 5) - 1);
   case Match_InvalidUImm5Plus1:

llvm/lib/Target/RISCV/Disassembler/RISCVDisassembler.cpp

@@ -461,6 +461,14 @@ static DecodeStatus decodeUImmNonZeroOperand(MCInst &Inst, uint32_t Imm,
   return decodeUImmOperand<N>(Inst, Imm, Address, Decoder);
 }
 
+static DecodeStatus decodeUImmZibiOperand(MCInst &Inst, uint32_t Imm,
+                                          int64_t Address,
+                                          const MCDisassembler *Decoder) {
+  assert(isUInt<5>(Imm) && "Invalid immediate");
+  Inst.addOperand(MCOperand::createImm(Imm ? Imm : -1LL));
+  return MCDisassembler::Success;
+}
+
 static DecodeStatus
 decodeUImmLog2XLenNonZeroOperand(MCInst &Inst, uint32_t Imm, int64_t Address,
                                  const MCDisassembler *Decoder) {

llvm/lib/Target/RISCV/MCTargetDesc/RISCVBaseInfo.h

@@ -310,6 +310,7 @@ enum OperandType : unsigned {
   OPERAND_UIMM4,
   OPERAND_UIMM5,
   OPERAND_UIMM5_NONZERO,
+  OPERAND_UIMM5_ZIBI,
   OPERAND_UIMM5_GT3,
   OPERAND_UIMM5_PLUS1,
   OPERAND_UIMM5_GE6_PLUS1,

llvm/lib/Target/RISCV/MCTargetDesc/RISCVMCCodeEmitter.cpp

@@ -97,6 +97,10 @@ class RISCVMCCodeEmitter : public MCCodeEmitter {
                              SmallVectorImpl<MCFixup> &Fixups,
                              const MCSubtargetInfo &STI) const;
 
+  uint64_t getImmOpValueZibi(const MCInst &MI, unsigned OpNo,
+                             SmallVectorImpl<MCFixup> &Fixups,
+                             const MCSubtargetInfo &STI) const;
+
   uint64_t getImmOpValue(const MCInst &MI, unsigned OpNo,
                          SmallVectorImpl<MCFixup> &Fixups,
                          const MCSubtargetInfo &STI) const;
@@ -559,6 +563,19 @@ RISCVMCCodeEmitter::getImmOpValueAsrN(const MCInst &MI, unsigned OpNo,
   return getImmOpValue(MI, OpNo, Fixups, STI);
 }
 
+uint64_t
+RISCVMCCodeEmitter::getImmOpValueZibi(const MCInst &MI, unsigned OpNo,
+                                      SmallVectorImpl<MCFixup> &Fixups,
+                                      const MCSubtargetInfo &STI) const {
+  const MCOperand &MO = MI.getOperand(OpNo);
+  assert(MO.isImm() && "Zibi operand must be an immediate");
+  int64_t Res = MO.getImm();
+  if (Res == -1)
+    return 0;
+
+  return Res;
+}
+
 uint64_t RISCVMCCodeEmitter::getImmOpValue(const MCInst &MI, unsigned OpNo,
                                            SmallVectorImpl<MCFixup> &Fixups,
                                            const MCSubtargetInfo &STI) const {

llvm/lib/Target/RISCV/RISCVFeatures.td

@@ -78,6 +78,12 @@ def FeatureStdExtE
     : RISCVExtension<2, 0, "Embedded Instruction Set with 16 GPRs">,
       RISCVExtensionBitmask<0, 4>;
 
+def FeatureStdExtZibi
+    : RISCVExperimentalExtension<0, 1, "Branch with Immediate">;
+def HasStdExtZibi : Predicate<"Subtarget->hasStdExtZibi()">,
+                      AssemblerPredicate<(all_of FeatureStdExtZibi),
+                                         "'Zibi' (Branch with Immediate)">;
+
 def FeatureStdExtZic64b
     : RISCVExtension<1, 0, "Cache Block Size Is 64 Bytes">;
 

llvm/lib/Target/RISCV/RISCVInstrFormats.td

@@ -498,6 +498,22 @@ class RVInstB<bits<3> funct3, RISCVOpcode opcode, dag outs, dag ins,
   let Inst{6-0} = opcode.Value;
 }
 
+class RVInstBIMM<bits<3> funct3, RISCVOpcode opcode, dag outs, dag ins,
+                 string opcodestr, string argstr>
+    : RVInst<outs, ins, opcodestr, argstr, [], InstFormatB> {
+  bits<12> imm12;
+  bits<5> cimm;
+  bits<5> rs1;
+  let Inst{31} = imm12{11};
+  let Inst{30-25} = imm12{9-4};
+  let Inst{24-20} = cimm;
+  let Inst{19-15} = rs1;
+  let Inst{14-12} = funct3;
+  let Inst{11-8} = imm12{3-0};
+  let Inst{7} = imm12{10};
+  let Inst{6-0} = opcode.Value;
+}
+
 class RVInstU<RISCVOpcode opcode, dag outs, dag ins, string opcodestr,
               string argstr>
     : RVInst<outs, ins, opcodestr, argstr, [], InstFormatU> {

llvm/lib/Target/RISCV/RISCVInstrInfo.td

@@ -2332,6 +2332,7 @@ include "RISCVInstrInfoZicbo.td"
 include "RISCVInstrInfoZicond.td"
 include "RISCVInstrInfoZicfiss.td"
 include "RISCVInstrInfoZilsd.td"
+include "RISCVInstrInfoZibi.td"
 
 // Scalar FP
 include "RISCVInstrInfoF.td"

llvm/lib/Target/RISCV/RISCVInstrInfoZibi.td

@@ -0,0 +1,44 @@
+//===-- RISCVInstrInfoZibi.td - 'Zibi' instructions --------*- tablegen -*-===//
+//
+// 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
+//
+//===----------------------------------------------------------------------===//
+///
+/// This file describes the RISC-V instructions for 'Zibi' (branch with imm).
+///
+//===----------------------------------------------------------------------===//
+
+// A 5-bit unsigned immediate representing 1-31 and -1. 00000 represents -1.
+def uimm5_zibi : RISCVOp<XLenVT>, ImmLeaf<XLenVT, [{
+    return (Imm != 0 && isUInt<5>(Imm)) || Imm == -1;
+}]> {
+  let ParserMatchClass = UImmAsmOperand<5, "Zibi">;
+  let EncoderMethod = "getImmOpValueZibi";
+  let DecoderMethod = "decodeUImmZibiOperand";
+  let MCOperandPredicate = [{
+    int64_t Imm;
+    if (!MCOp.evaluateAsConstantImm(Imm))
+      return false;
+    return (Imm >= 1 && Imm <= 31) || Imm == -1;
+  }];
+  let OperandType = "OPERAND_UIMM5_ZIBI";
+}
+
+class Branch_imm<bits<3> funct3, string opcodestr>
+    : RVInstBIMM<funct3, OPC_BRANCH, (outs),
+                 (ins GPR:$rs1, uimm5_zibi:$cimm, bare_simm13_lsb0:$imm12),
+                 opcodestr, "$rs1, $cimm, $imm12">,
+      Sched<[WriteJmp, ReadJmp]> {
+  let isBranch = 1;
+  let isTerminator = 1;
+  let hasSideEffects = 0;
+  let mayLoad = 0;
+  let mayStore = 0;
+}
+
+let Predicates = [HasStdExtZibi] in {
+  def BEQI : Branch_imm<0b010, "beqi">;
+  def BNEI : Branch_imm<0b011, "bnei">;
+} // Predicates = [HasStdExtZibi]

llvm/test/CodeGen/RISCV/attributes.ll

@@ -175,6 +175,7 @@
 ; RUN: llc -mtriple=riscv32 -mattr=+supm %s -o - | FileCheck --check-prefix=RV32SUPM %s
 ; RUN: llc -mtriple=riscv32 -mattr=+smctr  %s -o - | FileCheck --check-prefix=RV32SMCTR %s
 ; RUN: llc -mtriple=riscv32 -mattr=+ssctr  %s -o - | FileCheck --check-prefix=RV32SSCTR %s
+; RUN: llc -mtriple=riscv32 -mattr=+experimental-zibi %s -o - | FileCheck --check-prefix=RV32ZIBI %s
 
 ; RUN: llc -mtriple=riscv64 %s -o - | FileCheck %s
 ; RUN: llc -mtriple=riscv64 -mattr=+m %s -o - | FileCheck --check-prefixes=CHECK,RV64M %s
@@ -342,6 +343,7 @@
 ; RUN: llc -mtriple=riscv64 -mattr=+sdtrig  %s -o - | FileCheck --check-prefix=RV64SDTRIG %s
 ; RUN: llc -mtriple=riscv64 -mattr=+experimental-xqccmp %s -o - | FileCheck --check-prefix=RV64XQCCMP %s
 ; RUN: llc -mtriple=riscv64 -mattr=+experimental-p %s -o - | FileCheck --check-prefix=RV64P %s
+; RUN: llc -mtriple=riscv64 -mattr=+experimental-zibi %s -o - | FileCheck --check-prefix=RV64ZIBI %s
 
 
 ; Tests for profile features.
@@ -534,6 +536,7 @@
 ; RV32SMCTR: .attribute 5, "rv32i2p1_smctr1p0_sscsrind1p0"
 ; RV32SSCTR: .attribute 5, "rv32i2p1_sscsrind1p0_ssctr1p0"
 ; RV32P: .attribute 5, "rv32i2p1_p0p15"
+; RV32ZIBI: .attribute 5, "rv32i2p1_zibi0p1"
 
 ; RV64M: .attribute 5, "rv64i2p1_m2p0_zmmul1p0"
 ; RV64ZMMUL: .attribute 5, "rv64i2p1_zmmul1p0"
@@ -699,6 +702,7 @@
 ; RV64SDTRIG: .attribute 5, "rv64i2p1_sdtrig1p0"
 ; RV64XQCCMP: .attribute 5, "rv64i2p1_zca1p0_xqccmp0p3"
 ; RV64P: .attribute 5, "rv64i2p1_p0p15"
+; RV64ZIBI: .attribute 5, "rv64i2p1_zibi0p1"
 
 ; RVI20U32: .attribute 5, "rv32i2p1"
 ; RVI20U64: .attribute 5, "rv64i2p1"

llvm/test/CodeGen/RISCV/features-info.ll

@@ -52,6 +52,7 @@
 ; CHECK-NEXT:   experimental-xsfmclic            - 'XSfmclic' (SiFive CLIC Machine-mode CSRs).
 ; CHECK-NEXT:   experimental-xsfsclic            - 'XSfsclic' (SiFive CLIC Supervisor-mode CSRs).
 ; CHECK-NEXT:   experimental-zalasr              - 'Zalasr' (Load-Acquire and Store-Release Instructions).
+; CHECK-NEXT:   experimental-zibi                - 'Zibi' (Branch with Immediate).
 ; CHECK-NEXT:   experimental-zicfilp             - 'Zicfilp' (Landing pad).
 ; CHECK-NEXT:   experimental-zicfiss             - 'Zicfiss' (Shadow stack).
 ; CHECK-NEXT:   experimental-zvbc32e             - 'Zvbc32e' (Vector Carryless Multiplication with 32-bits elements).

llvm/test/MC/RISCV/zibi-invalid.s

@@ -0,0 +1,34 @@
+# RUN: not llvm-mc -triple=riscv32 --mattr=+experimental-zibi %s 2>&1 \
+# RUN:        | FileCheck %s --check-prefix=CHECK-ERROR
+# RUN: not llvm-mc -triple=riscv64 --mattr=+experimental-zibi %s 2>&1 \
+# RUN:        | FileCheck %s --check-prefix=CHECK-ERROR
+beqi a0, 0x0, 0x400
+# CHECK-ERROR: [[@LINE-1]]:10: error: immediate must be non-zero in the range [-1, 31]
+# CHECK-ERROR-LABEL: beqi a0, 0x0, 0x400
+beqi a0, 0x21, 0x400
+# CHECK-ERROR: [[@LINE-1]]:10: error: immediate must be non-zero in the range [-1, 31]
+# CHECK-ERROR-LABEL: beqi a0, 0x21, 0x400
+beqi a2, 0x10, -0x1f000
+# CHECK-ERROR: [[@LINE-1]]:16: error: immediate must be a multiple of 2 bytes in the range [-4096, 4094]
+# CHECK-ERROR-LABEL: beqi a2, 0x10, -0x1f000
+beqi a2, 0x10, 0x1000
+# CHECK-ERROR: [[@LINE-1]]:16: error: immediate must be a multiple of 2 bytes in the range [-4096, 4094]
+# CHECK-ERROR-LABEL: beqi a2, 0x10, 0x1000
+beqi a2, 0x10, 0x111
+# CHECK-ERROR: [[@LINE-1]]:16: error: immediate must be a multiple of 2 bytes in the range [-4096, 4094]
+# CHECK-ERROR-LABEL: beqi a2, 0x10, 0x111
+bnei a0, 0x0, 0x400
+# CHECK-ERROR: [[@LINE-1]]:10: error: immediate must be non-zero in the range [-1, 31]
+# CHECK-ERROR-LABEL: bnei a0, 0x0, 0x400
+bnei a0, 0x21, 0x400
+# CHECK-ERROR: [[@LINE-1]]:10: error: immediate must be non-zero in the range [-1, 31]
+# CHECK-ERROR-LABEL: bnei a0, 0x21, 0x400
+bnei a2, 0x10, -0x1f000
+# CHECK-ERROR: [[@LINE-1]]:16: error: immediate must be a multiple of 2 bytes in the range [-4096, 4094]
+# CHECK-ERROR-LABEL: bnei a2, 0x10, -0x1f000
+bnei a2, 0x10, 0x1000
+# CHECK-ERROR: [[@LINE-1]]:16: error: immediate must be a multiple of 2 bytes in the range [-4096, 4094]
+# CHECK-ERROR-LABEL: bnei a2, 0x10, 0x1000
+bnei a2, 0x10, 0x111
+# CHECK-ERROR: [[@LINE-1]]:16: error: immediate must be a multiple of 2 bytes in the range [-4096, 4094]
+# CHECK-ERROR-LABEL: bnei a2, 0x10, 0x111

llvm/test/MC/RISCV/zibi-valid.s

@@ -0,0 +1,63 @@
+# RUN: llvm-mc -triple=riscv32 -show-encoding --mattr=+experimental-zibi %s \
+# RUN:        | FileCheck %s --check-prefixes=CHECK-ENCODING,CHECK-ASM
+# RUN: llvm-mc -triple=riscv64 -show-encoding --mattr=+experimental-zibi %s \
+# RUN:        | FileCheck %s --check-prefixes=CHECK-ENCODING,CHECK-ASM
+# RUN: not llvm-mc -triple=riscv32 -show-encoding %s 2>&1 \
+# RUN:        | FileCheck %s --check-prefix=CHECK-ERROR
+# RUN: not llvm-mc -triple=riscv64 -show-encoding %s 2>&1 \
+# RUN:        | FileCheck %s --check-prefix=CHECK-ERROR
+# RUN: llvm-mc -triple=riscv32 -filetype=obj --mattr=+experimental-zibi %s \
+# RUN:        | llvm-objdump -d --mattr=+experimental-zibi --no-print-imm-hex  - \
+# RUN:        | FileCheck %s --check-prefix=CHECK-OBJ
+# RUN: llvm-mc -triple=riscv32 -filetype=obj --mattr=+experimental-zibi %s \
+# RUN:        | llvm-objdump -d - | FileCheck %s --check-prefix=CHECK-UNKNOWN
+# RUN: llvm-mc -triple=riscv64 -filetype=obj --mattr=+experimental-zibi %s \
+# RUN:        | llvm-objdump -d - | FileCheck %s --check-prefix=CHECK-UNKNOWN
+beqi a0, 1, 1024
+# CHECK-OBJ: beqi a0, 1, 0x400
+# CHECK-ASM: beqi a0, 1, 1024
+# CHECK-ENCODING: [0x63,0x20,0x15,0x40]
+# CHECK-ERROR: instruction requires the following: 'Zibi' (Branch with Immediate){{$}}
+# CHECK-UNKNOWN: 40152063 <unknown>
+beqi a5, -1, -1024
+# CHECK-OBJ: beqi a5, -1, 0xfffffc04
+# CHECK-ASM: beqi a5, -1, -1024
+# CHECK-ENCODING: [0xe3,0xa0,0x07,0xc0]
+# CHECK-ERROR: instruction requires the following: 'Zibi' (Branch with Immediate){{$}}
+# CHECK-UNKNOWN: c007a0e3 <unknown>
+beqi s0, 22, 0xffe
+# CHECK-OBJ: beqi s0, 22, 0x1006
+# CHECK-ASM: beqi s0, 22, 4094
+# CHECK-ENCODING: [0xe3,0x2f,0x64,0x7f]
+# CHECK-ERROR: instruction requires the following: 'Zibi' (Branch with Immediate){{$}}
+# CHECK-UNKNOWN: 7f642fe3 <unknown>
+beqi s1, 11, -4096
+# CHECK-OBJ: beqi s1, 11, 0xfffff00c
+# CHECK-ASM: beqi s1, 11, -4096
+# CHECK-ENCODING: [0x63,0xa0,0xb4,0x80]
+# CHECK-ERROR: instruction requires the following: 'Zibi' (Branch with Immediate){{$}}
+# CHECK-UNKNOWN: 80b4a063 <unknown>
+bnei a0, 1, 1024
+# CHECK-OBJ: bnei a0, 1, 0x410
+# CHECK-ASM: bnei a0, 1, 1024
+# CHECK-ENCODING: [0x63,0x30,0x15,0x40]
+# CHECK-ERROR: instruction requires the following: 'Zibi' (Branch with Immediate){{$}}
+# CHECK-UNKNOWN: 40153063 <unknown>
+bnei a5, -1, -1024
+# CHECK-OBJ: bnei a5, -1, 0xfffffc14
+# CHECK-ASM: bnei a5, -1, -1024
+# CHECK-ENCODING: [0xe3,0xb0,0x07,0xc0]
+# CHECK-ERROR: instruction requires the following: 'Zibi' (Branch with Immediate){{$}}
+# CHECK-UNKNOWN: c007b0e3 <unknown>
+bnei s0, 22, 0xffe
+# CHECK-OBJ: bnei s0, 22, 0x1016
+# CHECK-ASM: bnei s0, 22, 4094
+# CHECK-ENCODING: [0xe3,0x3f,0x64,0x7f]
+# CHECK-ERROR: instruction requires the following: 'Zibi' (Branch with Immediate){{$}}
+# CHECK-UNKNOWN: 7f643fe3 <unknown>
+bnei s1, 11, -4096
+# CHECK-OBJ: bnei s1, 11, 0xfffff01c
+# CHECK-ASM: bnei s1, 11, -4096
+# CHECK-ENCODING: [0x63,0xb0,0xb4,0x80]
+# CHECK-ERROR: instruction requires the following: 'Zibi' (Branch with Immediate){{$}}
+# CHECK-UNKNOWN: 80b4b063 <unknown>

llvm/unittests/TargetParser/RISCVISAInfoTest.cpp

@@ -1182,6 +1182,7 @@ R"(All available -march extensions for RISC-V
 
 Experimental extensions
     p                    0.15
+    zibi                 0.1
     zicfilp              1.0       This is a long dummy description
     zicfiss              1.0
     zalasr               0.1