[RISCV][MC] Add support for experimental Zfbfmin extension

Provides MC layer support for Zfbfmin: scalar BF16 conversions. As documented, this extension includes FLH, FSH, FMV.H.X, and FMH.X.H as defined in Zfh/Zfhmin, but doesn't require either extension. No Zfbfinxmin has been defined (though you would expect one in the future, for symmetry with Zfhinxmin). See issue riscv/riscv-bfloat16#27. Differential Revision: https://reviews.llvm.org/D147610
llvm · May 19, 2023 · 35ff5eb · 35ff5eb
1 parent b6bf28f
commit 35ff5eb
Show file tree

Hide file tree

Showing 15 changed files with 156 additions and 6 deletions.
diff --git a/clang/test/Preprocessor/riscv-target-features.c b/clang/test/Preprocessor/riscv-target-features.c
@@ -67,6 +67,7 @@
 // CHECK-NOT: __riscv_zicond {{.*$}}
 // CHECK-NOT: __riscv_smaia {{.*$}}
 // CHECK-NOT: __riscv_ssaia {{.*$}}
+// CHECK-NOT: __riscv_zfbfmin {{.*$}}
 
 // RUN: %clang -target riscv32-unknown-linux-gnu -march=rv32i -x c -E -dM %s \
 // RUN: -o - | FileCheck %s
@@ -674,3 +675,11 @@
 // RUN: -march=rv64issaia1p0 -x c -E -dM %s \
 // RUN: -o - | FileCheck --check-prefix=CHECK-SSAIA-EXT %s
 // CHECK-SSAIA-EXT: __riscv_ssaia  1000000{{$}}
+
+// RUN: %clang -target riscv32 -menable-experimental-extensions \
+// RUN: -march=rv32izfbfmin0p6 -x c -E -dM %s \
+// RUN: -o - | FileCheck --check-prefix=CHECK-ZFBFMIN-EXT %s
+// RUN: %clang -target riscv64 -menable-experimental-extensions \
+// RUN: -march=rv64izfbfmin0p6 -x c -E -dM %s \
+// RUN: -o - | FileCheck --check-prefix=CHECK-ZFBFMIN-EXT %s
+// CHECK-ZFBFMIN-EXT: __riscv_zfbfmin 6000{{$}}
diff --git a/llvm/docs/RISCVUsage.rst b/llvm/docs/RISCVUsage.rst
@@ -204,6 +204,9 @@ The primary goal of experimental support is to assist in the process of ratifica
 ``experimental-zfa``
   LLVM implements the `0.2 draft specification <https://github.com/riscv/riscv-isa-manual/releases/download/draft-20230131-c0b298a/zfa-20230414.pdf>`__.
 
+``experimental-zfbfmin``
+  LLVM implements assembler support for the `0.6 draft specification <https://github.com/riscv/riscv-bfloat16/releases/tag/main>`_.
+
 ``experimental-zicond``
   LLVM implements the `1.0-rc1 draft specification <https://github.com/riscv/riscv-zicond/releases/tag/v1.0-rc1>`__.
 

diff --git a/llvm/docs/ReleaseNotes.rst b/llvm/docs/ReleaseNotes.rst
@@ -180,6 +180,8 @@ Changes to the RISC-V Backend
 * Add sifive-x280 processor.
 * Zve32f is no longer allowed with Zfinx. Zve64d is no longer allowed with
   Zdinx.
+* Assembly support was added for the experimental Zfbfmin (scalar BF16
+  conversions) extension.
 
 Changes to the WebAssembly Backend
 ----------------------------------

diff --git a/llvm/lib/Support/RISCVISAInfo.cpp b/llvm/lib/Support/RISCVISAInfo.cpp
@@ -147,6 +147,7 @@ static const RISCVSupportedExtension SupportedExperimentalExtensions[] = {
     {"zcmp", RISCVExtensionVersion{1, 0}},
     {"zcmt", RISCVExtensionVersion{1, 0}},
     {"zfa", RISCVExtensionVersion{0, 2}},
+    {"zfbfmin", RISCVExtensionVersion{0, 6}},
     {"zicond", RISCVExtensionVersion{1, 0}},
     {"zvfh", RISCVExtensionVersion{0, 1}},
     {"ztso", RISCVExtensionVersion{0, 1}},

diff --git a/llvm/lib/Target/RISCV/RISCVFeatures.td b/llvm/lib/Target/RISCV/RISCVFeatures.td
@@ -611,6 +611,21 @@ def FeatureStdExtSsaia
                        "excluding the machine-level CSRs and behavior not "
                        "directly visible to supervisor level.)", []>;
 
+def FeatureStdExtZfbfmin
+    : SubtargetFeature<"experimental-zfbfmin", "HasStdExtZfbfmin", "true",
+                       "'Zfbfmin' (Scalar BF16 Converts)",
+                       [FeatureStdExtF]>;
+def HasStdExtZfbfmin : Predicate<"Subtarget->hasStdExtZfbfmin()">,
+                                 AssemblerPredicate<(all_of FeatureStdExtZfbfmin),
+                                 "'Zfbfmin' (Scalar BF16 Converts)">;
+
+def HasHalfFPLoadStoreMove
+    : Predicate<"Subtarget->hasHalfFPLoadStoreMove()">,
+                AssemblerPredicate<(any_of FeatureStdExtZfh, FeatureStdExtZfhmin, FeatureStdExtZfbfmin),
+                                    "'Zfh' (Half-Precision Floating-Point) or "
+                                    "'Zfhmin' (Half-Precision Floating-Point Minimal) or "
+                                    "'Zfbfmin' (Scalar BF16 Converts)">;
+
 //===----------------------------------------------------------------------===//
 // Vendor extensions
 //===----------------------------------------------------------------------===//

diff --git a/llvm/lib/Target/RISCV/RISCVInstrInfo.td b/llvm/lib/Target/RISCV/RISCVInstrInfo.td
@@ -1904,6 +1904,7 @@ include "RISCVInstrInfoZc.td"
 include "RISCVInstrInfoZk.td"
 include "RISCVInstrInfoV.td"
 include "RISCVInstrInfoZfa.td"
+include "RISCVInstrInfoZfbfmin.td"
 include "RISCVInstrInfoZfh.td"
 include "RISCVInstrInfoZicbo.td"
 include "RISCVInstrInfoZicond.td"

diff --git a/llvm/lib/Target/RISCV/RISCVInstrInfoZfbfmin.td b/llvm/lib/Target/RISCV/RISCVInstrInfoZfbfmin.td
@@ -0,0 +1,25 @@
+//===-- RISCVInstrInfoZfbfmin.td - 'Zfbfmin' 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 from the standard 'Zfbfmin'
+// extension, providing scalar conversion instructions for BFloat16.
+// This version is still experimental as the 'Zfbfmin' extension hasn't been
+// ratified yet.
+//
+//===----------------------------------------------------------------------===//
+
+//===----------------------------------------------------------------------===//
+// Instructions
+//===----------------------------------------------------------------------===//
+
+let Predicates = [HasStdExtZfbfmin] in {
+def FCVT_BF16_S : FPUnaryOp_r_frm<0b0100010, 0b01000, FPR16, FPR32, "fcvt.bf16.s">,
+                  Sched<[WriteFCvtF32ToF16, ReadFCvtF32ToF16]>;
+def FCVT_S_BF16 : FPUnaryOp_r_frm<0b0100000, 0b00110, FPR32, FPR16, "fcvt.s.bf16">,
+                  Sched<[WriteFCvtF32ToF16, ReadFCvtF32ToF16]>;
+} // Predicates = [HasStdExtZfbfmin]
diff --git a/llvm/lib/Target/RISCV/RISCVInstrInfoZfh.td b/llvm/lib/Target/RISCV/RISCVInstrInfoZfh.td
@@ -90,14 +90,14 @@ defvar HDINXmin = [HDmin, HD_INXmin, HD_INX32min];
 // Instructions
 //===----------------------------------------------------------------------===//
 
-let Predicates = [HasStdExtZfhOrZfhmin] in {
+let Predicates = [HasHalfFPLoadStoreMove] in {
 def FLH : FPLoad_r<0b001, "flh", FPR16, WriteFLD16>;
 
 // Operands for stores are in the order srcreg, base, offset rather than
 // reflecting the order these fields are specified in the instruction
 // encoding.
 def FSH : FPStore_r<0b001, "fsh", FPR16, WriteFST16>;
-} // Predicates = [HasStdExtZfhOrZfhmin]
+} // Predicates = [HasHalfFPLoadStoreMove]
 
 let SchedRW = [WriteFMA16, ReadFMA16, ReadFMA16, ReadFMA16] in {
 defm FMADD_H  : FPFMA_rrr_frm_m<OPC_MADD,  0b10, "fmadd.h",  HINX>;
@@ -151,15 +151,15 @@ defm FCVT_H_S : FPUnaryOp_r_frm_m<0b0100010, 0b00000, HFINXmin, "fcvt.h.s">,
 defm FCVT_S_H : FPUnaryOp_r_m<0b0100000, 0b00010, 0b000, FHINXmin, "fcvt.s.h">,
                Sched<[WriteFCvtF16ToF32, ReadFCvtF16ToF32]>;
 
-let Predicates = [HasStdExtZfhOrZfhmin] in {
+let Predicates = [HasHalfFPLoadStoreMove] in {
 let mayRaiseFPException = 0, IsSignExtendingOpW = 1 in
 def FMV_X_H : FPUnaryOp_r<0b1110010, 0b00000, 0b000, GPR, FPR16, "fmv.x.h">,
               Sched<[WriteFMovF16ToI16, ReadFMovF16ToI16]>;
 
 let mayRaiseFPException = 0 in
 def FMV_H_X : FPUnaryOp_r<0b1111010, 0b00000, 0b000, FPR16, GPR, "fmv.h.x">,
               Sched<[WriteFMovI16ToF16, ReadFMovI16ToF16]>;
-} // Predicates = [HasStdExtZfhOrZfhmin]
+} // Predicates = [HasHalfFPLoadStoreMove]
 
 let SchedRW = [WriteFCmp16, ReadFCmp16, ReadFCmp16] in {
 defm FEQ_H : FPCmp_rr_m<0b1010010, 0b010, "feq.h", HINX, /*Commutable*/1>;

diff --git a/llvm/lib/Target/RISCV/RISCVSubtarget.h b/llvm/lib/Target/RISCV/RISCVSubtarget.h
@@ -123,6 +123,9 @@ class RISCVSubtarget : public RISCVGenSubtargetInfo {
   bool hasStdExtZfhOrZfhminOrZhinxOrZhinxmin() const {
     return hasStdExtZfhOrZfhmin() || hasStdExtZhinxOrZhinxmin();
   }
+  bool hasHalfFPLoadStoreMove() const {
+    return HasStdExtZfh || HasStdExtZfhmin || HasStdExtZfbfmin;
+  }
   bool is64Bit() const { return IsRV64; }
   MVT getXLenVT() const { return XLenVT; }
   unsigned getXLen() const { return XLen; }

diff --git a/llvm/test/CodeGen/RISCV/attributes.ll b/llvm/test/CodeGen/RISCV/attributes.ll
@@ -74,6 +74,7 @@
 ; RUN: llc -mtriple=riscv32 -mattr=+experimental-zicond %s -o - | FileCheck --check-prefix=RV32ZICOND %s
 ; RUN: llc -mtriple=riscv32 -mattr=+experimental-smaia %s -o - | FileCheck --check-prefixes=CHECK,RV32SMAIA %s
 ; RUN: llc -mtriple=riscv32 -mattr=+experimental-ssaia %s -o - | FileCheck --check-prefixes=CHECK,RV32SSAIA %s
+; RUN: llc -mtriple=riscv32 -mattr=+experimental-zfbfmin %s -o - | FileCheck --check-prefixes=CHECK,RV32ZFBFMIN %s
 
 ; RUN: llc -mtriple=riscv64 %s -o - | FileCheck %s
 ; RUN: llc -mtriple=riscv64 -mattr=+m %s -o - | FileCheck --check-prefixes=CHECK,RV64M %s
@@ -155,6 +156,7 @@
 ; RUN: llc -mtriple=riscv64 -mattr=+experimental-zicond %s -o - | FileCheck --check-prefix=RV64ZICOND %s
 ; RUN: llc -mtriple=riscv64 -mattr=+experimental-smaia %s -o - | FileCheck --check-prefixes=CHECK,RV64SMAIA %s
 ; RUN: llc -mtriple=riscv64 -mattr=+experimental-ssaia %s -o - | FileCheck --check-prefixes=CHECK,RV64SSAIA %s
+; RUN: llc -mtriple=riscv64 -mattr=+experimental-zfbfmin %s -o - | FileCheck --check-prefixes=CHECK,RV64ZFBFMIN %s
 
 ; CHECK: .attribute 4, 16
 
@@ -231,6 +233,7 @@
 ; RV32ZICOND: .attribute 5, "rv32i2p1_zicond1p0"
 ; RV32SMAIA: .attribute 5, "rv32i2p1_smaia1p0"
 ; RV32SSAIA: .attribute 5, "rv32i2p1_ssaia1p0"
+; RV32ZFBFMIN: .attribute 5, "rv32i2p1_f2p2_zicsr2p0_zfbfmin0p6"
 
 ; RV64M: .attribute 5, "rv64i2p1_m2p0"
 ; RV64ZMMUL: .attribute 5, "rv64i2p1_zmmul1p0"
@@ -311,6 +314,7 @@
 ; RV64ZICOND: .attribute 5, "rv64i2p1_zicond1p0"
 ; RV64SMAIA: .attribute 5, "rv64i2p1_smaia1p0"
 ; RV64SSAIA: .attribute 5, "rv64i2p1_ssaia1p0"
+; RV64ZFBFMIN: .attribute 5, "rv64i2p1_f2p2_zicsr2p0_zfbfmin0p6"
 
 define i32 @addi(i32 %a) {
   %1 = add i32 %a, 1

diff --git a/llvm/test/MC/RISCV/attribute-arch.s b/llvm/test/MC/RISCV/attribute-arch.s
@@ -263,3 +263,6 @@
 
 .attribute arch, "rv32i_ssaia1p0"
 # CHECK: attribute      5, "rv32i2p1_ssaia1p0"
+
+.attribute arch, "rv32if_zfbfmin0p6"
+# CHECK: .attribute     5, "rv32i2p1_f2p2_zicsr2p0_zfbfmin0p6"
diff --git a/llvm/test/MC/RISCV/rv32zfbfmin-invalid.s b/llvm/test/MC/RISCV/rv32zfbfmin-invalid.s
@@ -0,0 +1,28 @@
+# RUN: not llvm-mc -triple riscv32 -mattr=+experimental-zfbfmin,+d < %s 2>&1 | \
+# RUN:   FileCheck %s
+# RUN: not llvm-mc -triple riscv64 -mattr=+experimental-zfbfmin,+d < %s 2>&1 | \
+# RUN:   FileCheck %s
+
+# Out of range immediates
+## simm12
+flh ft1, -2049(a0) # CHECK: :[[@LINE]]:10: error: operand must be a symbol with %lo/%pcrel_lo/%tprel_lo modifier or an integer in the range [-2048, 2047]
+fsh ft2, 2048(a1) # CHECK: :[[@LINE]]:10: error: operand must be a symbol with %lo/%pcrel_lo/%tprel_lo modifier or an integer in the range [-2048, 2047]
+
+# Memory operand not formatted correctly
+flh ft1, a0, -200 # CHECK: :[[@LINE]]:14: error: invalid operand for instruction
+
+# Invalid register names
+flh ft15, 100(a0) # CHECK: :[[@LINE]]:5: error: invalid operand for instruction
+flh ft1, 100(a10) # CHECK: :[[@LINE]]:14: error: expected register
+
+# Integer registers where FP regs are expected
+fmv.x.h fs7, a2 # CHECK: :[[@LINE]]:9: error: invalid operand for instruction
+
+# FP registers where integer regs are expected
+fmv.h.x a8, ft2 # CHECK: :[[@LINE]]:9: error: invalid operand for instruction
+
+# Attempting to use fcvt instructions from zfhmin
+fcvt.s.h fa0, ft0 # CHECK: [[@LINE]]:1: error: instruction requires the following: 'Zfh' (Half-Precision Floating-Point) or 'Zfhmin' (Half-Precision Floating-Point Minimal)
+fcvt.h.s ft2, fa2 # CHECK: [[@LINE]]:1: error: instruction requires the following: 'Zfh' (Half-Precision Floating-Point) or 'Zfhmin' (Half-Precision Floating-Point Minimal)
+fcvt.d.h fa0, ft0 # CHECK: [[@LINE]]:1: error: instruction requires the following: 'Zfh' (Half-Precision Floating-Point) or 'Zfhmin' (Half-Precision Floating-Point Minimal)
+fcvt.h.d ft2, fa2 # CHECK: [[@LINE]]:1: error: instruction requires the following: 'Zfh' (Half-Precision Floating-Point) or 'Zfhmin' (Half-Precision Floating-Point Minimal)
diff --git a/llvm/test/MC/RISCV/rv32zfbfmin-valid.s b/llvm/test/MC/RISCV/rv32zfbfmin-valid.s
@@ -0,0 +1,56 @@
+# RUN: llvm-mc %s -triple=riscv32 -mattr=+experimental-zfbfmin,+f -riscv-no-aliases -show-encoding \
+# RUN:     | FileCheck -check-prefixes=CHECK-ASM,CHECK-ASM-AND-OBJ %s
+# RUN: llvm-mc %s -triple=riscv64 -mattr=+experimental-zfbfmin,+f -riscv-no-aliases -show-encoding \
+# RUN:     | FileCheck -check-prefixes=CHECK-ASM,CHECK-ASM-AND-OBJ %s
+# RUN: llvm-mc -filetype=obj -triple=riscv32 -mattr=+experimental-zfbfmin,+d < %s \
+# RUN:     | llvm-objdump --mattr=+experimental-zfbfmin,+f -M no-aliases -d -r - \
+# RUN:     | FileCheck --check-prefix=CHECK-ASM-AND-OBJ %s
+# RUN: llvm-mc -filetype=obj -triple=riscv64 -mattr=+experimental-zfbfmin,+d < %s \
+# RUN:     | llvm-objdump --mattr=+experimental-zfbfmin,+f -M no-aliases -d -r - \
+# RUN:     | FileCheck --check-prefix=CHECK-ASM-AND-OBJ %s
+
+# CHECK-ASM-AND-OBJ: flh ft0, 12(a0)
+# CHECK-ASM: encoding: [0x07,0x10,0xc5,0x00]
+flh f0, 12(a0)
+# CHECK-ASM-AND-OBJ: flh ft1, 4(ra)
+# CHECK-ASM: encoding: [0x87,0x90,0x40,0x00]
+flh f1, +4(ra)
+# CHECK-ASM-AND-OBJ: flh ft2, -2048(a3)
+# CHECK-ASM: encoding: [0x07,0x91,0x06,0x80]
+flh f2, -2048(x13)
+# CHECK-ASM-AND-OBJ: flh ft3, -2048(s1)
+# CHECK-ASM: encoding: [0x87,0x91,0x04,0x80]
+flh f3, %lo(2048)(s1)
+# CHECK-ASM-AND-OBJ: flh ft4, 2047(s2)
+# CHECK-ASM: encoding: [0x07,0x12,0xf9,0x7f]
+flh f4, 2047(s2)
+# CHECK-ASM-AND-OBJ: flh ft5, 0(s3)
+# CHECK-ASM: encoding: [0x87,0x92,0x09,0x00]
+flh f5, 0(s3)
+
+# CHECK-ASM-AND-OBJ: fsh ft6, 2047(s4)
+# CHECK-ASM: encoding: [0xa7,0x1f,0x6a,0x7e]
+fsh f6, 2047(s4)
+# CHECK-ASM-AND-OBJ: fsh ft7, -2048(s5)
+# CHECK-ASM: encoding: [0x27,0x90,0x7a,0x80]
+fsh f7, -2048(s5)
+# CHECK-ASM-AND-OBJ: fsh fs0, -2048(s6)
+# CHECK-ASM: encoding: [0x27,0x10,0x8b,0x80]
+fsh f8, %lo(2048)(s6)
+# CHECK-ASM-AND-OBJ: fsh fs1, 999(s7)
+# CHECK-ASM: encoding: [0xa7,0x93,0x9b,0x3e]
+fsh f9, 999(s7)
+
+# CHECK-ASM-AND-OBJ: fmv.x.h a2, fs7
+# CHECK-ASM: encoding: [0x53,0x86,0x0b,0xe4]
+fmv.x.h a2, fs7
+# CHECK-ASM-AND-OBJ: fmv.h.x ft1, a6
+# CHECK-ASM: encoding: [0xd3,0x00,0x08,0xf4]
+fmv.h.x ft1, a6
+
+# CHECK-ASM-AND-OBJ: fcvt.s.bf16 fa0, ft0
+# CHECK-ASM: encoding: [0x53,0x75,0x60,0x40]
+fcvt.s.bf16 fa0, ft0
+# CHECK-ASM-AND-OBJ: fcvt.bf16.s ft2, fa2
+# CHECK-ASM: encoding: [0x53,0x71,0x86,0x44]
+fcvt.bf16.s ft2, fa2
diff --git a/llvm/test/MC/RISCV/rv64zhinx-invalid.s b/llvm/test/MC/RISCV/rv64zhinx-invalid.s
@@ -1,7 +1,7 @@
 # RUN: not llvm-mc -triple riscv64 -mattr=+zhinx %s 2>&1 | FileCheck %s
 
 # Not support float registers
-flh fa4, 12(sp) # CHECK: :[[@LINE]]:1: error: instruction requires the following: 'Zfh' (Half-Precision Floating-Point) or 'Zfhmin' (Half-Precision Floating-Point Minimal){{$}}
+flh fa4, 12(sp) # CHECK: :[[@LINE]]:1: error: instruction requires the following: 'Zfh' (Half-Precision Floating-Point) or 'Zfhmin' (Half-Precision Floating-Point Minimal) or 'Zfbfmin' (Scalar BF16 Converts){{$}}
 
 # Invalid instructions
 fsh a5, 12(sp) # CHECK: :[[@LINE]]:5: error: invalid operand for instruction

diff --git a/llvm/test/MC/RISCV/rv64zhinxmin-invalid.s b/llvm/test/MC/RISCV/rv64zhinxmin-invalid.s
@@ -1,7 +1,7 @@
 # RUN: not llvm-mc -triple riscv64 -mattr=+zhinxmin %s 2>&1 | FileCheck %s
 
 # Not support float registers
-flh fa4, 12(sp) # CHECK: :[[@LINE]]:1: error: instruction requires the following: 'Zfh' (Half-Precision Floating-Point) or 'Zfhmin' (Half-Precision Floating-Point Minimal){{$}}
+flh fa4, 12(sp) # CHECK: :[[@LINE]]:1: error: instruction requires the following: 'Zfh' (Half-Precision Floating-Point) or 'Zfhmin' (Half-Precision Floating-Point Minimal) or 'Zfbfmin' (Scalar BF16 Converts){{$}}
 
 # Invalid instructions
 fsh a5, 12(sp) # CHECK: :[[@LINE]]:5: error: invalid operand for instruction