[RISCV] Remove Zfbfmin dependency from Zvfbfmin. (#75851)

Zvfbfmin does not have any scalar operands making this an unnecessary
dependency. The spec was just updated to remove this. See
riscv/riscv-bfloat16@86d7a74

This fixes a correctness issue where Xsfvfwmaccqqq was incorrectly
depending on Zfbfmin. The SiFive CPUs that support Xsfvfwmaccqqq do not
implement Zfbfmin, but do implement Zvfbfmin based on a previous
understanding that it only requires Zve32f. I've added tests for this
feature to raise the bar for adding dependencies to it in the future.

Author: topperc

llvm/lib/Support/RISCVISAInfo.cpp

@@ -998,7 +998,7 @@ static const char *ImpliedExtsV[] = {"zvl128b", "zve64d"};
 static const char *ImpliedExtsXTHeadVdot[] = {"v"};
 static const char *ImpliedExtsXSfvcp[] = {"zve32x"};
 static const char *ImpliedExtsXSfvfnrclipxfqf[] = {"zve32f"};
-static const char *ImpliedExtsXSfvfwmaccqqq[] = {"zve32f", "zvfbfmin"};
+static const char *ImpliedExtsXSfvfwmaccqqq[] = {"zvfbfmin"};
 static const char *ImpliedExtsXSfvqmaccdod[] = {"zve32x"};
 static const char *ImpliedExtsXSfvqmaccqoq[] = {"zve32x"};
 static const char *ImpliedExtsZacas[] = {"a"};
@@ -1028,8 +1028,8 @@ static const char *ImpliedExtsZve32x[] = {"zvl32b", "zicsr"};
 static const char *ImpliedExtsZve64d[] = {"zve64f", "d"};
 static const char *ImpliedExtsZve64f[] = {"zve64x", "zve32f"};
 static const char *ImpliedExtsZve64x[] = {"zve32x", "zvl64b"};
-static const char *ImpliedExtsZvfbfmin[] = {"zve32f", "zfbfmin"};
-static const char *ImpliedExtsZvfbfwma[] = {"zvfbfmin"};
+static const char *ImpliedExtsZvfbfmin[] = {"zve32f"};
+static const char *ImpliedExtsZvfbfwma[] = {"zvfbfmin", "zfbfmin"};
 static const char *ImpliedExtsZvfh[] = {"zvfhmin", "zfhmin"};
 static const char *ImpliedExtsZvfhmin[] = {"zve32f"};
 static const char *ImpliedExtsZvkn[] = {"zvkb", "zvkned", "zvknhb", "zvkt"};

llvm/lib/Target/RISCV/RISCVFeatures.td

@@ -472,15 +472,15 @@ def HasStdExtZfbfmin : Predicate<"Subtarget->hasStdExtZfbfmin()">,
 def FeatureStdExtZvfbfmin
     : SubtargetFeature<"experimental-zvfbfmin", "HasStdExtZvfbfmin", "true",
                        "'Zvbfmin' (Vector BF16 Converts)",
-                       [FeatureStdExtZve32f, FeatureStdExtZfbfmin]>;
+                       [FeatureStdExtZve32f]>;
 def HasStdExtZvfbfmin : Predicate<"Subtarget->hasStdExtZvfbfmin()">,
                                   AssemblerPredicate<(all_of FeatureStdExtZvfbfmin),
                                   "'Zvfbfmin' (Vector BF16 Converts)">;
 
 def FeatureStdExtZvfbfwma
     : SubtargetFeature<"experimental-zvfbfwma", "HasStdExtZvfbfwma", "true",
                        "'Zvfbfwma' (Vector BF16 widening mul-add)",
-                       [FeatureStdExtZvfbfmin]>;
+                       [FeatureStdExtZvfbfmin, FeatureStdExtZfbfmin]>;
 def HasStdExtZvfbfwma : Predicate<"Subtarget->hasStdExtZvfbfwma()">,
                                   AssemblerPredicate<(all_of FeatureStdExtZvfbfwma),
                                   "'Zvfbfwma' (Vector BF16 widening mul-add)">;

llvm/test/CodeGen/RISCV/attributes.ll

@@ -48,6 +48,7 @@
 ; RUN: llc -mtriple=riscv32 -mattr=+xcvmem %s -o - | FileCheck --check-prefix=RV32XCVMEM %s
 ; RUN: llc -mtriple=riscv32 -mattr=+xcvsimd %s -o - | FileCheck --check-prefix=RV32XCVSIMD %s
 ; RUN: llc -mtriple=riscv32 -mattr=+xcvbi %s -o - | FileCheck --check-prefix=RV32XCVBI %s
+; RUN: llc -mtriple=riscv32 -mattr=+xsfvfwmaccqqq %s -o - | FileCheck --check-prefix=RV32XSFVFWMACCQQQ %s
 ; RUN: llc -mtriple=riscv32 -mattr=+xtheadcmo %s -o - | FileCheck --check-prefix=RV32XTHEADCMO %s
 ; RUN: llc -mtriple=riscv32 -mattr=+xtheadcondmov %s -o - | FileCheck --check-prefix=RV32XTHEADCONDMOV %s
 ; RUN: llc -mtriple=riscv32 -mattr=+xtheadfmemidx %s -o - | FileCheck --check-prefix=RV32XTHEADFMEMIDX %s
@@ -134,6 +135,7 @@
 ; RUN: llc -mtriple=riscv64 -mattr=+svpbmt %s -o - | FileCheck --check-prefixes=CHECK,RV64SVPBMT %s
 ; RUN: llc -mtriple=riscv64 -mattr=+svinval %s -o - | FileCheck --check-prefixes=CHECK,RV64SVINVAL %s
 ; RUN: llc -mtriple=riscv64 -mattr=+xventanacondops %s -o - | FileCheck --check-prefixes=CHECK,RV64XVENTANACONDOPS %s
+; RUN: llc -mtriple=riscv64 -mattr=+xsfvfwmaccqqq %s -o - | FileCheck --check-prefix=RV64XSFVFWMACCQQQ %s
 ; RUN: llc -mtriple=riscv64 -mattr=+xtheadba %s -o - | FileCheck --check-prefixes=CHECK,RV64XTHEADBA %s
 ; RUN: llc -mtriple=riscv64 -mattr=+xtheadbb %s -o - | FileCheck --check-prefixes=CHECK,RV64XTHEADBB %s
 ; RUN: llc -mtriple=riscv64 -mattr=+xtheadbs %s -o - | FileCheck --check-prefixes=CHECK,RV64XTHEADBS %s
@@ -232,6 +234,7 @@
 ; RV32XCVMEM: .attribute 5, "rv32i2p1_xcvmem1p0"
 ; RV32XCVSIMD: .attribute 5, "rv32i2p1_xcvsimd1p0"
 ; RV32XCVBI: .attribute 5, "rv32i2p1_xcvbi1p0"
+; RV32XSFVFWMACCQQQ: .attribute 5, "rv32i2p1_f2p2_zicsr2p0_zve32f1p0_zve32x1p0_zvfbfmin0p8_zvl32b1p0_xsfvfwmaccqqq1p0"
 ; RV32XTHEADCMO: .attribute 5, "rv32i2p1_xtheadcmo1p0"
 ; RV32XTHEADCONDMOV: .attribute 5, "rv32i2p1_xtheadcondmov1p0"
 ; RV32XTHEADFMEMIDX: .attribute 5, "rv32i2p1_f2p2_zicsr2p0_xtheadfmemidx1p0"
@@ -271,7 +274,7 @@
 ; RV32SMAIA: .attribute 5, "rv32i2p1_smaia1p0"
 ; RV32SSAIA: .attribute 5, "rv32i2p1_ssaia1p0"
 ; RV32ZFBFMIN: .attribute 5, "rv32i2p1_f2p2_zicsr2p0_zfbfmin0p8"
-; RV32ZVFBFMIN: .attribute 5, "rv32i2p1_f2p2_zicsr2p0_zfbfmin0p8_zve32f1p0_zve32x1p0_zvfbfmin0p8_zvl32b1p0"
+; RV32ZVFBFMIN: .attribute 5, "rv32i2p1_f2p2_zicsr2p0_zve32f1p0_zve32x1p0_zvfbfmin0p8_zvl32b1p0"
 ; RV32ZVFBFWMA: .attribute 5, "rv32i2p1_f2p2_zicsr2p0_zfbfmin0p8_zve32f1p0_zve32x1p0_zvfbfmin0p8_zvfbfwma0p8_zvl32b1p0"
 ; RV32ZACAS: .attribute 5, "rv32i2p1_a2p1_zacas1p0"
 ; RV32ZICFILP: .attribute 5, "rv32i2p1_zicfilp0p4"
@@ -318,6 +321,7 @@
 ; RV64SVPBMT: .attribute 5, "rv64i2p1_svpbmt1p0"
 ; RV64SVINVAL: .attribute 5, "rv64i2p1_svinval1p0"
 ; RV64XVENTANACONDOPS: .attribute 5, "rv64i2p1_xventanacondops1p0"
+; RV64XSFVFWMACCQQQ: .attribute 5, "rv64i2p1_f2p2_zicsr2p0_zve32f1p0_zve32x1p0_zvfbfmin0p8_zvl32b1p0_xsfvfwmaccqqq1p0"
 ; RV64XTHEADBA: .attribute 5, "rv64i2p1_xtheadba1p0"
 ; RV64XTHEADBB: .attribute 5, "rv64i2p1_xtheadbb1p0"
 ; RV64XTHEADBS: .attribute 5, "rv64i2p1_xtheadbs1p0"
@@ -361,7 +365,7 @@
 ; RV64SMAIA: .attribute 5, "rv64i2p1_smaia1p0"
 ; RV64SSAIA: .attribute 5, "rv64i2p1_ssaia1p0"
 ; RV64ZFBFMIN: .attribute 5, "rv64i2p1_f2p2_zicsr2p0_zfbfmin0p8"
-; RV64ZVFBFMIN: .attribute 5, "rv64i2p1_f2p2_zicsr2p0_zfbfmin0p8_zve32f1p0_zve32x1p0_zvfbfmin0p8_zvl32b1p0"
+; RV64ZVFBFMIN: .attribute 5, "rv64i2p1_f2p2_zicsr2p0_zve32f1p0_zve32x1p0_zvfbfmin0p8_zvl32b1p0"
 ; RV64ZVFBFWMA: .attribute 5, "rv64i2p1_f2p2_zicsr2p0_zfbfmin0p8_zve32f1p0_zve32x1p0_zvfbfmin0p8_zvfbfwma0p8_zvl32b1p0"
 ; RV64ZACAS: .attribute 5, "rv64i2p1_a2p1_zacas1p0"
 ; RV64ZICFILP: .attribute 5, "rv64i2p1_zicfilp0p4"

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

@@ -277,7 +277,7 @@
 # CHECK: .attribute     5, "rv32i2p1_f2p2_zicsr2p0_zfbfmin0p8"
 
 .attribute arch, "rv32i_zvfbfmin0p8"
-# CHECK: .attribute     5, "rv32i2p1_f2p2_zicsr2p0_zfbfmin0p8_zve32f1p0_zve32x1p0_zvfbfmin0p8_zvl32b1p0"
+# CHECK: .attribute     5, "rv32i2p1_f2p2_zicsr2p0_zve32f1p0_zve32x1p0_zvfbfmin0p8_zvl32b1p0"
 
 .attribute arch, "rv32i_zvfbfwma0p8"
 # CHECK: .attribute     5, "rv32i2p1_f2p2_zicsr2p0_zfbfmin0p8_zve32f1p0_zve32x1p0_zvfbfmin0p8_zvfbfwma0p8_zvl32b1p0"
@@ -311,3 +311,6 @@
 
 .attribute arch, "rv32i_zicfilp0p4"
 # CHECK: attribute      5, "rv32i2p1_zicfilp0p4"
+
+.attribute arch, "rv64i_xsfvfwmaccqqq"
+# CHECK: attribute      5, "rv64i2p1_f2p2_zicsr2p0_zve32f1p0_zve32x1p0_zvfbfmin0p8_zvl32b1p0_xsfvfwmaccqqq1p0"