[RISCV] Decouple V and Zve64*

[eopXD]

Summary

Now with existing macros to imply elen and elen_fp for rvv, we should decouple
the implication between V and Zve*.

[eopXD]

Update code.

[eopXD]

Update code.

[eopXD]

Update code: adjust testcase due to change of implication.

[eopXD]

Update code.

[jacquesguan]

I did some similar change in my revision https://reviews.llvm.org/D117854.

[eopXD]

In D117920#3263202, @jacquesguan wrote:

I did some similar change in my revision https://reviews.llvm.org/D117854.

Yeah I guess we can do that all in one commit.
Thank you for doing it.

llvm/lib/Support/RISCVISAInfo.cpp

Error RISCVISAInfo::checkDependency() {
 
   // Additional dependency checks.
   // TODO: The 'q' extension requires rv64.
   // TODO: It is illegal to specify 'e' extensions with 'f' and 'd'.
 
   return Error::success();
 }
 
-static const char *ImpliedExtsV[] = {"zvl128b", "zve64d", "f", "d"};
+static const char *ImpliedExtsV[] = {"zvl128b", "zve32x", "f", "d"};
 static const char *ImpliedExtsZfh[] = {"zfhmin"};
 static const char *ImpliedExtsZve64d[] = {"zve64f"};
 static const char *ImpliedExtsZve64f[] = {"zve64x", "zve32f"};
 static const char *ImpliedExtsZve64x[] = {"zve32x", "zvl64b"};
 static const char *ImpliedExtsZve32f[] = {"zve32x"};
 static const char *ImpliedExtsZve32x[] = {"zvl32b"};
 static const char *ImpliedExtsZvl65536b[] = {"zvl32768b"};
 static const char *ImpliedExtsZvl32768b[] = {"zvl16384b"};
for (auto Ext : Exts) {
     }
   }
 }
 
 void RISCVISAInfo::updateMaxELen() {
   // handles EEW restriction by sub-extension zve
   for (auto Ext : Exts) {
     StringRef ExtName = Ext.first;
+    if (ExtName == "v") {
+      MaxELen = MaxELenFp = 64;
+    }
     bool IsZveExt = ExtName.consume_front("zve");
     if (IsZveExt) {
       if (ExtName.back() == 'f')
         MaxELenFp = std::max(MaxELenFp, 32u);
       if (ExtName.back() == 'd')
         MaxELenFp = std::max(MaxELenFp, 64u);
       ExtName = ExtName.drop_back();
       unsigned ZveELen;