Add support for alternative register names, useful for instructions whose operands are logically equivalent to existing registers, but happen to be printed specially. For example, an instruciton that prints d0[0] instead of s0.

Patch by Jim Grosbach.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@133940 91177308-0d34-0410-b5e6-96231b3b80d8

utils/TableGen/CodeGenTarget.cpp

@@ -164,6 +164,11 @@ CodeGenRegBank &CodeGenTarget::getRegBank() const {
   return *RegBank;
 }
 
+void CodeGenTarget::ReadRegAltNameIndices() const {
+  RegAltNameIndices = Records.getAllDerivedDefinitions("RegAltNameIndex");
+  std::sort(RegAltNameIndices.begin(), RegAltNameIndices.end(), LessRecord());
+}
+
 /// getRegisterByName - If there is a register with the specific AsmName,
 /// return it.
 const CodeGenRegister *CodeGenTarget::getRegisterByName(StringRef Name) const {