[RISCV] Make Zvfh depend on Zfhmin.

[jacquesguan]

Summary

According to the v spec, the Zvfh extension depends on the Zve32f and Zfhmin extensions.

[craig.topper]

We can’t add dependencies in RISCVFeatures.td that are not also RISCVISAInfo.cpp. The ELF attributes are generated from RISCVFeatures.td so they need to match.

[jacquesguan]

Add dependency in RISCVISAInfo.cpp.

[jacquesguan]

In D150016#4323724, @craig.topper wrote:

We can’t add dependencies in RISCVFeatures.td that are not also RISCVISAInfo.cpp. The ELF attributes are generated from RISCVFeatures.td so they need to match.

Done.

[craig.topper]

llvm/lib/Support/RISCVISAInfo.cpp

868–869

I guess this can be deleted now?

[craig.topper]

I hadn't noticed that the Zfinx and Zdinx mentions were removed from the vector spec repo in October 2021 after the 1.0 pdf was made in September in 2021. I guess Zve* extensions aren't compatible with Zfinx/Zdinx. I'll make another patch to fix that.

[jacquesguan]

rebase main.

[craig.topper]

llvm/lib/Support/RISCVISAInfo.cpp

868–869

This can be removed.

[jacquesguan]

Address comment.

llvm/lib/Support/RISCVISAInfo.cpp

868–869

Done.

[craig.topper]

LGTM

llvm/lib/Support/RISCVISAInfo.cpp

Error RISCVISAInfo::checkDependency() {
   bool HasVector = Exts.count("zve32x") != 0;
   bool HasZvl = MinVLen != 0;
   bool HasZcmt = Exts.count("zcmt") != 0;
   bool HasZcd = Exts.count("zcd") != 0;
 
   if (HasF && HasZfinx)
     return createStringError(errc::invalid_argument,
                              "'f' and 'zfinx' extensions are incompatible");
 
-  if (Exts.count("zvfh") && !Exts.count("zfh") && !Exts.count("zfhmin"))
-    return createStringError(
-        errc::invalid_argument,
-        "'zvfh' requires 'zfh' or 'zfhmin extension to also be specified");
-
   if (HasZvl && !HasVector)
     return createStringError(
         errc::invalid_argument,
         "'zvl*b' requires 'v' or 'zve*' extension to also be specified");
 
   if (Exts.count("zvbb") && !HasVector)
     return createStringError(
         errc::invalid_argument,
         "'zvbb' requires 'v' or 'zve*' extension to also be specified");

 static const char *ImpliedExtsZkn[] = {"zbkb", "zbkc", "zbkx",
                                        "zkne", "zknd", "zknh"};
 static const char *ImpliedExtsZks[] = {"zbkb", "zbkc", "zbkx", "zksed", "zksh"};
 static const char *ImpliedExtsZve32f[] = {"zve32x", "f"};
 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 *ImpliedExtsZvfh[] = {"zve32f"};
+static const char *ImpliedExtsZvfh[] = {"zve32f", "zfhmin"};
 static const char *ImpliedExtsZvkn[] = {"zvbb", "zvbc", "zvkned", "zvknhb",
                                         "zvkt"};
 static const char *ImpliedExtsZvkng[] = {"zvkg", "zvkn"};
 static const char *ImpliedExtsZvknhb[] = {"zvknha"};
 static const char *ImpliedExtsZvks[] = {"zvbb", "zvbc", "zvksed", "zvksh",
                                         "zvkt"};
 static const char *ImpliedExtsZvksg[] = {"zvks", "zvkg"};
 static const char *ImpliedExtsZvl1024b[] = {"zvl512b"};

llvm/lib/Target/RISCV/RISCVFeatures.td

def HasVInstructionsAnyF : Predicate<"Subtarget->hasVInstructionsAnyF()">,
       AssemblerPredicate<
           (any_of FeatureStdExtZve32f),
           "'V' (Vector Extension for Application Processors), 'Zve32f', "
           "'Zve64f' or 'Zve64d' (Vector Extensions for Embedded Processors)">;
 
 def FeatureStdExtZvfh
     : SubtargetFeature<"experimental-zvfh", "HasStdExtZvfh", "true",
                        "'Zvfh' (Vector Half-Precision Floating-Point)",
-                       [FeatureStdExtZve32f]>;
+                       [FeatureStdExtZve32f, FeatureStdExtZfhmin]>;
 
 def HasStdExtZfhOrZvfh
     : Predicate<"Subtarget->hasStdExtZfh() || Subtarget->hasStdExtZvfh()">,
                 AssemblerPredicate<(any_of FeatureStdExtZfh, FeatureStdExtZvfh),
                                    "'Zfh' (Half-Precision Floating-Point) or "
                                    "'Zvfh' (Vector Half-Precision Floating-Point)">;
 
 def FeatureStdExtZicbom

llvm/lib/Target/RISCV/RISCVSubtarget.h

bool isRegisterReservedByUser(Register i) const {
     return UserReservedRegister[i];
   }
 
   bool hasMacroFusion() const { return hasLUIADDIFusion(); }
 
   // Vector codegen related methods.
   bool hasVInstructions() const { return HasStdExtZve32x; }
   bool hasVInstructionsI64() const { return HasStdExtZve64x; }
-  bool hasVInstructionsF16() const {
-    return HasStdExtZvfh && hasStdExtZfhOrZfhmin();
-  }
+  bool hasVInstructionsF16() const { return HasStdExtZvfh; }
   // FIXME: Consider Zfinx in the future
   bool hasVInstructionsF32() const { return HasStdExtZve32f && HasStdExtF; }
   // FIXME: Consider Zdinx in the future
   bool hasVInstructionsF64() const { return HasStdExtZve64d && HasStdExtD; }
   // F16 and F64 both require F32.
   bool hasVInstructionsAnyF() const { return hasVInstructionsF32(); }
   unsigned getMaxInterleaveFactor() const {
     return hasVInstructions() ? MaxInterleaveFactor : 1;