[RISCV] Add support for custom instructions for Sifive S76.

[garvitgupta08]

Summary

Support for below instruction is added

1. CFLUSH.D.L1
2. CDISCARD.D.L1
3. CEASE

Additionally, Zihintpause extension is added to sifive s76 for pause
instruction.

Spec - https://sifive.cdn.prismic.io/sifive/767804da-53b2-4893-97d5-b7c030ae0a94_s76mc_core_complex_manual_21G3.pdf

[craig.topper]

llvm/lib/Support/RISCVISAInfo.cpp

149

Put this with xsfvcp

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

566

Keep SiFive extensions together.

llvm/lib/Target/RISCV/RISCVFeatures.td

769

Keep SiFive extensions together

771

I believe the SiFive documentation uses SCIE not SFCIE?

llvm/lib/Target/RISCV/RISCVInstrInfoXSf.td

508

I don't think these are restricted to RV64. They're in the E76 core complex manual too.

510

Don't exceed 80 columns

510

Use SF_ instead of Sfv_

[garvitgupta08]

Addressed the comments

[craig.topper]

llvm/lib/Support/RISCVISAInfo.cpp

148

Alphabetize.

llvm/lib/Target/RISCV/RISCVFeatures.td

757

Drop "for S76"

[craig.topper]

llvm/docs/ReleaseNotes.rst

213

SCIE->CIE since the S already stands for SiFive.

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

562

SCIE -> SiFive CIE

[garvitgupta08]

Addressed the changes. I do not have commit access, could you please commit this differential on my behalf? Thanks.

[craig.topper]

In D153370#4447817, @garvitgupta08 wrote:

Addressed the changes. I do not have commit access, could you please commit this differential on my behalf? Thanks.

Yes. Can you provide the name and email address for the git log.

[garvitgupta08]

In D153370#4447824, @craig.topper wrote:

In D153370#4447817, @garvitgupta08 wrote:

Addressed the changes. I do not have commit access, could you please commit this differential on my behalf? Thanks.

Yes. Can you provide the name and email address for the git log.

Name - Garvit Gupta
Email - [e-mail]

clang/test/Driver/riscv-cpus.c

 // MCPU-SIFIVE-S54: "-target-feature" "+zicsr" "-target-feature" "+zifencei"
 // MCPU-SIFIVE-S54: "-target-abi" "lp64d"
 
 // mcpu with mabi option
 // RUN: %clang --target=riscv64 -### -c %s 2>&1 -mcpu=sifive-s76 | FileCheck -check-prefix=MCPU-SIFIVE-S76 %s
 // MCPU-SIFIVE-S76: "-nostdsysteminc" "-target-cpu" "sifive-s76"
 // MCPU-SIFIVE-S76: "-target-feature" "+m" "-target-feature" "+a" "-target-feature" "+f" "-target-feature" "+d"
 // MCPU-SIFIVE-S76: "-target-feature" "+c"
-// MCPU-SIFIVE-S76: "-target-feature" "+zicsr" "-target-feature" "+zifencei"
+// MCPU-SIFIVE-S76: "-target-feature" "+zicsr" "-target-feature" "+zifencei" "-target-feature" "+zihintpause"
+// MCPU-SIFIVE-S76: "-target-feature" "+xsfcie"
 // MCPU-SIFIVE-S76: "-target-abi" "lp64d"
 
 // mcpu with default march
 // RUN: %clang --target=riscv64 -### -c %s 2>&1 -mcpu=sifive-u54 | FileCheck -check-prefix=MCPU-SIFIVE-U54 %s
 // MCPU-SIFIVE-U54: "-nostdsysteminc" "-target-cpu" "sifive-u54"
 // MCPU-SIFIVE-U54: "-target-feature" "+m" "-target-feature" "+a" "-target-feature" "+f" "-target-feature" "+d"
 // MCPU-SIFIVE-U54: "-target-feature" "+c"
 // MCPU-SIFIVE-U54: "-target-feature" "+zicsr" "-target-feature" "+zifencei"

llvm/docs/RISCVUsage.rst

 ``XSfvcp``
   LLVM implements `version 1.0.0 of the SiFive Vector Coprocessor Interface (VCIX) Software Specification <https://sifive.cdn.prismic.io/sifive/c3829e36-8552-41f0-a841-79945784241b_vcix-spec-software.pdf>`_ by SiFive.  All instructions are prefixed with `sf.vc.` as described in the specification, and the riscv-toolchain-convention document linked above.
 
 ``XCVbitmanip``
   LLVM implements `version 1.3.1 of the Core-V bit manipulation custom instructions specification <https://github.com/openhwgroup/cv32e40p/blob/62bec66b36182215e18c9cf10f723567e23878e9/docs/source/instruction_set_extensions.rst>`_ by Core-V.  All instructions are prefixed with `cv.` as described in the specification.
 
 ``XCVmac``
   LLVM implements `version 1.3.1 of the Core-V Multiply-Accumulate (MAC) custom instructions specification <https://github.com/openhwgroup/cv32e40p/blob/4f024fe4b15a68b76615b0630c07a6745c620da7/docs/source/instruction_set_extensions.rst>`_ by Core-V.  All instructions are prefixed with `cv.mac.` as described in the specification. These instructions are only available for riscv32 at this time.
+
+``XSfcie``
+  LLVM implements `version 1.0.0 of the SiFive Custom Instruction Extension (CIE) Software Specification <https://sifive.cdn.prismic.io/sifive/767804da-53b2-4893-97d5-b7c030ae0a94_s76mc_core_complex_manual_21G3.pdf>`_ by SiFive.  All custom instruction are added as described in the specification, and the riscv-toolchain-convention document linked above. These instructions are only available for S76 processor at this time.

llvm/docs/ReleaseNotes.rst

 * Adds support for the vendor-defined XTHeadCondMov (conditional move) extension.
 * Adds support for the vendor-defined XTHeadMac (multiply-accumulate instructions) extension.
 * Added support for the vendor-defined XTHeadMemPair (two-GPR memory operations)
   extension disassembler/assembler.
 * Added support for the vendor-defined XTHeadMemIdx (indexed memory operations)
   extension disassembler/assembler.
 * Added support for the vendor-defined Xsfvcp (SiFive VCIX) extension
   disassembler/assembler.
+* Added support for the vendor-defined Xsfcie (SiFive CIE) extension
+  disassembler/assembler.
 * Support for the now-ratified Zawrs extension is no longer experimental.
 * Adds support for the vendor-defined XTHeadCmo (cache management operations) extension.
 * Adds support for the vendor-defined XTHeadSync (multi-core synchronization instructions) extension.
 * Added support for the vendor-defined XTHeadFMemIdx (indexed memory operations for floating point) extension.
 * Assembler support for RV64E was added.
 * Assembler support was added for the experimental Zicond (integer conditional
   operations) extension.
 * I, F, D, and A extension versions have been update to the 20191214 spec versions.

llvm/lib/Support/RISCVISAInfo.cpp

static const RISCVSupportedExtension SupportedExtensions[] = {
 
     {"svinval", RISCVExtensionVersion{1, 0}},
     {"svnapot", RISCVExtensionVersion{1, 0}},
     {"svpbmt", RISCVExtensionVersion{1, 0}},
 
     {"v", RISCVExtensionVersion{1, 0}},
 
     // vendor-defined ('X') extensions
+    {"xsfcie", RISCVExtensionVersion{1, 0}},
     {"xsfvcp", RISCVExtensionVersion{1, 0}},
     {"xtheadba", RISCVExtensionVersion{1, 0}},
     {"xtheadbb", RISCVExtensionVersion{1, 0}},
     {"xtheadbs", RISCVExtensionVersion{1, 0}},
     {"xtheadcmo", RISCVExtensionVersion{1, 0}},
     {"xtheadcondmov", RISCVExtensionVersion{1, 0}},
     {"xtheadfmemidx", RISCVExtensionVersion{1, 0}},
     {"xtheadmac", RISCVExtensionVersion{1, 0}},
static const RISCVSupportedExtension SupportedExtensions[] = {
     {"zvl2048b", RISCVExtensionVersion{1, 0}},
     {"zvl256b", RISCVExtensionVersion{1, 0}},
     {"zvl32768b", RISCVExtensionVersion{1, 0}},
     {"zvl32b", RISCVExtensionVersion{1, 0}},
     {"zvl4096b", RISCVExtensionVersion{1, 0}},
     {"zvl512b", RISCVExtensionVersion{1, 0}},
     {"zvl64b", RISCVExtensionVersion{1, 0}},
     {"zvl65536b", RISCVExtensionVersion{1, 0}},
     {"zvl8192b", RISCVExtensionVersion{1, 0}},
 };
 
 // NOTE: This table should be sorted alphabetically by extension name.
 static const RISCVSupportedExtension SupportedExperimentalExtensions[] = {
     {"smaia", RISCVExtensionVersion{1, 0}},
     {"ssaia", RISCVExtensionVersion{1, 0}},
 
     {"zfa", RISCVExtensionVersion{0, 2}},
     {"zfbfmin", RISCVExtensionVersion{0, 6}},

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

TRY_TO_DECODE_FEATURE(RISCV::FeatureVendorXTHeadMemPair,
                           "XTHeadMemPair custom opcode table");
     TRY_TO_DECODE_FEATURE(RISCV::FeatureVendorXTHeadSync,
                           DecoderTableTHeadSync32,
                           "XTHeadSync custom opcode table");
     TRY_TO_DECODE_FEATURE(RISCV::FeatureVendorXTHeadVdot, DecoderTableTHeadV32,
                           "XTHeadVdot custom opcode table");
     TRY_TO_DECODE_FEATURE(RISCV::FeatureVendorXSfvcp, DecoderTableXSfvcp32,
                           "SiFive VCIX custom opcode table");
+    TRY_TO_DECODE_FEATURE(RISCV::FeatureVendorXSfcie, DecoderTableXSfcie32,
+                          "Sifive CIE custom opcode table");
     TRY_TO_DECODE_FEATURE(RISCV::FeatureVendorXCVbitmanip,
                           DecoderTableXCVbitmanip32,
                           "CORE-V Bit Manipulation custom opcode table");
     TRY_TO_DECODE_FEATURE(RISCV::FeatureVendorXCVmac, DecoderTableXCVmac32,
                           "CORE-V MAC custom opcode table");
     TRY_TO_DECODE(true, DecoderTable32, "RISCV32 table");
 
     return MCDisassembler::Fail;
   }
 
   if (Bytes.size() < 2) {
     Size = 0;

llvm/lib/Target/RISCV/RISCVFeatures.td

 def FeatureVendorXSfvcp
     : SubtargetFeature<"xsfvcp", "HasVendorXSfvcp", "true",
                        "XSfvcp (SiFive Custom Vector Coprocessor Interface Instructions)",
                        [FeatureStdExtZve32x]>;
 def HasVendorXSfvcp : Predicate<"Subtarget->hasVendorXSfvcp()">,
                                 AssemblerPredicate<(all_of FeatureVendorXSfvcp),
                                 "'XSfvcp' (SiFive Custom Vector Coprocessor Interface Instructions)">;
 
+def FeatureVendorXSfcie
+    : SubtargetFeature<"xsfcie", "HasVendorXSfcie", "true",
+                       "'XSfcie' (SiFive Custom Instruction Extension SCIE.)">;
+def HasVendorXSfcie : Predicate<"Subtarget->hasVendorXSfcie()">,
+                        AssemblerPredicate<(all_of FeatureVendorXSfcie),
+                        "'XSfcie' (SiFive Custom Instruction Extension SCIE.)">;
 
 def FeatureVendorXCVbitmanip
     : SubtargetFeature<"xcvbitmanip", "HasVendorXCVbitmanip", "true",
                        "'XCVbitmanip' (Bit Manipulation)">;
 def HasVendorXCVbitmanip : Predicate<"Subtarget->hasVendorXCVbitmanip()">,
                                 AssemblerPredicate<(all_of FeatureVendorXCVbitmanip),
                                 "'XCVbitmanip' (Bit Manipulation)">;
 
 def FeatureVendorXCVmac
     : SubtargetFeature<"xcvmac", "HasVendorXCVmac", "true",
                        "'XCVmac' (Multiply-Accumulate)">;
 def HasVendorXCVmac : Predicate<"Subtarget->hasVendorXCVmac()">,
                                 AssemblerPredicate<(all_of FeatureVendorXCVmac),
                                 "'XCVmac' (Multiply-Accumulate)">;
 
 //===----------------------------------------------------------------------===//
 // LLVM specific features and extensions
 //===----------------------------------------------------------------------===//
 

llvm/lib/Target/RISCV/RISCVInstrInfoXSf.td

foreach VtiToWti = AllWidenableIntVectors in {
     defm : VPatVC_XVV<"vvw", "VVW", wti, vti, vti.Vector, vti.RegClass>;
     if !ge(vti.SEW, 16) then {
       defm : VPatVC_XVV<"fvw", "F" # vti.SEW # "VW", wti, vti,
                         GetFTypeInfo<vti.SEW>.Scalar,
                         GetFTypeInfo<vti.SEW>.ScalarRegClass, payload1>;
     }
   }
 }
+
+let Predicates = [HasVendorXSfcie] in {
+let hasSideEffects = 1, mayLoad = 0, mayStore = 0, DecoderNamespace = "XSfcie" in {
+def SF_CFLUSH_D_L1 : RVInstI<0b000, OPC_SYSTEM, (outs), (ins GPR:$rs1), "cflush.d.l1","$rs1">,
+                             Sched<[]> {
+  let rd = 0;
+  let imm12 = {0b1111,0b1100,0b0000};
+}
+
+def SF_CDISCARD_D_L1 : RVInstI<0b000, OPC_SYSTEM, (outs), (ins GPR:$rs1), "cdiscard.d.l1","$rs1">,
+                               Sched<[]> {
+  let rd = 0;
+  let imm12 = {0b1111,0b1100,0b0010};
+}
+
+def SF_CEASE : RVInstI<0b000, OPC_SYSTEM, (outs), (ins), "cease","">,  Sched<[]> {
+  let rs1 = 0;
+  let rd = 0;
+  let imm12 = {0b0011,0b0000,0b0101};
+}
+}
+def : InstAlias<"cflush.d.l1", (SF_CFLUSH_D_L1 X0)>;
+def : InstAlias<"cdiscard.d.l1", (SF_CDISCARD_D_L1 X0)>;
+} // Predicates = [HasVendorXScie]

llvm/lib/Target/RISCV/RISCVProcessors.td

 def SIFIVE_S76 : RISCVProcessorModel<"sifive-s76",
                                      SiFive7Model,
                                      [Feature64Bit,
                                       FeatureStdExtZifencei,
                                       FeatureStdExtM,
                                       FeatureStdExtA,
                                       FeatureStdExtF,
                                       FeatureStdExtD,
-                                      FeatureStdExtC],
+                                      FeatureStdExtC,
+                                      FeatureStdExtZihintpause,
+                                      FeatureVendorXSfcie],
                                      [TuneSiFive7]>;
 
 def SIFIVE_U54 : RISCVProcessorModel<"sifive-u54",
                                      RocketModel,
                                      [Feature64Bit,
                                       FeatureStdExtZifencei,
                                       FeatureStdExtM,
                                       FeatureStdExtA,

llvm/test/MC/RISCV/attribute-arch.s

 .attribute arch, "rv32i_zfbfmin0p6"
 # CHECK: .attribute     5, "rv32i2p1_f2p2_zicsr2p0_zfbfmin0p6"
 
 .attribute arch, "rv32i_zvfbfmin0p6"
 # CHECK: .attribute     5, "rv32i2p1_f2p2_zicsr2p0_zve32f1p0_zve32x1p0_zvfbfmin0p6_zvl32b1p0"
 
 .attribute arch, "rv32i_zvfbfwma0p6"
 # CHECK: .attribute     5, "rv32i2p1_f2p2_zicsr2p0_zve32f1p0_zve32x1p0_zvfbfwma0p6_zvl32b1p0"
+
+.attribute arch, "rv64i_xsfcie"
+# CHECK: attribute      5, "rv64i2p1_xsfcie1p0"

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

+# SCIE - SiFive Custom Instructions Extension.
+# RUN: not llvm-mc -triple riscv32 -mattr=-xsfcie < %s 2>&1 | FileCheck %s
+# RUN: not llvm-mc -triple riscv64 -mattr=-xsfcie < %s 2>&1 | FileCheck %s
+
+cflush.d.l1 0x10 # CHECK: :[[@LINE]]:13: error: invalid operand for instruction
+
+cdiscard.d.l1 0x10 # CHECK: :[[@LINE]]:15: error: invalid operand for instruction
+
+cflush.d.l1 # CHECK: :[[@LINE]]:1: error: instruction requires the following: 'XSfcie' (SiFive Custom Instruction Extension SCIE.)
+
+cdiscard.d.l1 # CHECK: :[[@LINE]]:1: error: instruction requires the following: 'XSfcie' (SiFive Custom Instruction Extension SCIE.)
+
+cflush.d.l1 x0 # CHECK: :[[@LINE]]:1: error: instruction requires the following: 'XSfcie' (SiFive Custom Instruction Extension SCIE.)
+
+cflush.d.l1 x7 # CHECK: :[[@LINE]]:1: error: instruction requires the following: 'XSfcie' (SiFive Custom Instruction Extension SCIE.)
+
+cdiscard.d.l1 x0 # CHECK: :[[@LINE]]:1: error: instruction requires the following: 'XSfcie' (SiFive Custom Instruction Extension SCIE.)
+
+cdiscard.d.l1 x7 # CHECK: :[[@LINE]]:1: error: instruction requires the following: 'XSfcie' (SiFive Custom Instruction Extension SCIE.)
+
+cease x1 # CHECK: :[[@LINE]]:7: error: invalid operand for instruction
+
+cease 0x10 # CHECK: :[[@LINE]]:7: error: invalid operand for instruction
+
+cease # CHECK: :[[@LINE]]:1: error: instruction requires the following: 'XSfcie' (SiFive Custom Instruction Extension SCIE.)

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

+# SCIE - SiFive Custom Instructions Extension.
+# RUN: llvm-mc %s -triple=riscv32 -mattr=+xsfcie -riscv-no-aliases -show-encoding \
+# RUN:     | FileCheck -check-prefixes=CHECK-ENC,CHECK-INST %s
+# RUN: llvm-mc %s -triple=riscv64 -mattr=+xsfcie -riscv-no-aliases -show-encoding \
+# RUN:     | FileCheck -check-prefixes=CHECK-ENC,CHECK-INST %s
+# RUN: llvm-mc -filetype=obj -triple riscv32 -mattr=+xsfcie < %s \
+# RUN:     | llvm-objdump --mattr=+xsfcie -M no-aliases -d - \
+# RUN:     | FileCheck -check-prefix=CHECK-INST %s
+# RUN: llvm-mc -filetype=obj -triple riscv64 -mattr=+xsfcie < %s \
+# RUN:     | llvm-objdump --mattr=+xsfcie -M no-aliases -d - \
+# RUN:     | FileCheck -check-prefix=CHECK-INST %s
+# RUN: llvm-mc %s -triple=riscv64 -mcpu=sifive-s76 -riscv-no-aliases -show-encoding \
+# RUN:     | FileCheck -check-prefixes=CHECK-ENC,CHECK-INST %s
+# RUN: llvm-mc -filetype=obj -triple riscv64 -mcpu=sifive-s76 < %s \
+# RUN:     | llvm-objdump --mcpu=sifive-s76 -M no-aliases -d - \
+# RUN:     | FileCheck -check-prefix=CHECK-INST %s
+
+# CHECK-INST: cflush.d.l1     zero
+# CHECK-ENC: encoding: [0x73,0x00,0x00,0xfc]
+# CHECK-INST: cflush.d.l1     zero
+# CHECK-ENC: encoding: [0x73,0x00,0x00,0xfc]
+cflush.d.l1 x0
+cflush.d.l1
+
+# CHECK-INST: cflush.d.l1     t2
+# CHECK-ENC: encoding: [0x73,0x80,0x03,0xfc]
+cflush.d.l1 x7
+
+# CHECK-INST: cdiscard.d.l1   zero
+# CHECK-ENC: encoding: [0x73,0x00,0x20,0xfc]
+# CHECK-INST: cdiscard.d.l1     zero
+# CHECK-ENC: encoding: [0x73,0x00,0x20,0xfc]
+cdiscard.d.l1 x0
+cdiscard.d.l1
+
+# CHECK-INST: cdiscard.d.l1   t2
+# CHECK-ENC: encoding: [0x73,0x80,0x23,0xfc]
+cdiscard.d.l1 x7
+
+# CHECK-INST: cease
+# CHECK-ENC: encoding: [0x73,0x00,0x50,0x30]
+cease