[mips] Added -mfp64 and -mfp32 options.

These options specify 64-bit FP registers and 32-bit FP registers respectively.

When using -mfp32, the FPU has 16x double-precision registers overlapping with
the 32x single-precision registers (each double-precision register overlaps
two single-precision registers).

When using -mfp64, the FPU has 32x double-precision registers overlapping with
the 32x single-precision registers (each double-precision register overlaps
with one single-precision register and has an additional 32-bits).

MSA requires -mfp64.



git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@192899 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Driver/Tools.cpp b/lib/Driver/Tools.cpp
index 68a5fe8..d6ddd02 100644
--- a/lib/Driver/Tools.cpp
+++ b/lib/Driver/Tools.cpp
@@ -982,6 +982,8 @@
                    "dspr2");
   AddTargetFeature(Args, Features, options::OPT_mmsa, options::OPT_mno_msa,
                    "msa");
+  AddTargetFeature(Args, Features, options::OPT_mfp64, options::OPT_mfp32,
+                   "fp64");
 }
 
 void Clang::AddMIPSTargetArgs(const ArgList &Args,