[mips] Use early exit in MipsAsmParser::matchCPURegisterName(). NFC.

[dsanders]

The patch LGTM but could you change the message to something like '[mips] Use early exit in MipsAsmParser::matchCPURegisterName(). NFC'?

[vkalintiris]

• [mips] Refactor code to gain an extra identation level. No functional change.

[tomatabacu]

Closed by commit rL217774 (authored by @tomatabacu).

llvm/trunk/lib/Target/Mips/AsmParser/MipsAsmParser.cpp

CC = StringSwitch<unsigned>(Name)
            .Case("t4", 12)
            .Case("t5", 13)
            .Case("t6", 14)
            .Case("t7", 15)
            .Case("t8", 24)
            .Case("t9", 25)
            .Default(-1);
 
-  if (isABI_N32() || isABI_N64()) {
-    // Although SGI documentation just cuts out t0-t3 for n32/n64,
-    // GNU pushes the values of t0-t3 to override the o32/o64 values for t4-t7
-    // We are supporting both cases, so for t0-t3 we'll just push them to t4-t7.
-    if (8 <= CC && CC <= 11)
-      CC += 4;
+  if (!(isABI_N32() || isABI_N64()))
+    return CC;
+
 
-    if (CC == -1)
-      CC = StringSwitch<unsigned>(Name)
-               .Case("a4", 8)
-               .Case("a5", 9)
-               .Case("a6", 10)
-               .Case("a7", 11)
-               .Case("kt0", 26)
-               .Case("kt1", 27)
-               .Default(-1);
-  }
 
   return CC;
 }
 
 int MipsAsmParser::matchFPURegisterName(StringRef Name) {
 
   if (Name[0] == 'f') {
     StringRef NumString = Name.substr(1);