MIPS/Clang: handleTargetFeatures, add +fp64 if +msa and no other +-fp (llvm#92728)

Commit: d59bc6b
Clang/MIPS: Add +fp64 if MSA and no explicit -mfp option (llvm#91949)
added +fp64 for `clang`, while not for `clang -cc1`. So

   clang -cc1 -triple=mips -target-feature +msa -S

will emit an asm source file without ".module fp=64".

Author: wzssyqa

clang/lib/Basic/Targets/Mips.h

@@ -324,6 +324,7 @@ class LLVM_LIBRARY_VISIBILITY MipsTargetInfo : public TargetInfo {
     FPMode = getDefaultFPMode();
     bool OddSpregGiven = false;
     bool StrictAlign = false;
+    bool FpGiven = false;
 
     for (const auto &Feature : Features) {
       if (Feature == "+single-float")
@@ -348,13 +349,16 @@ class LLVM_LIBRARY_VISIBILITY MipsTargetInfo : public TargetInfo {
         HasMSA = true;
       else if (Feature == "+nomadd4")
         DisableMadd4 = true;
-      else if (Feature == "+fp64")
+      else if (Feature == "+fp64") {
         FPMode = FP64;
-      else if (Feature == "-fp64")
+        FpGiven = true;
+      } else if (Feature == "-fp64") {
         FPMode = FP32;
-      else if (Feature == "+fpxx")
+        FpGiven = true;
+      } else if (Feature == "+fpxx") {
         FPMode = FPXX;
-      else if (Feature == "+nan2008")
+        FpGiven = true;
+      } else if (Feature == "+nan2008")
         IsNan2008 = true;
       else if (Feature == "-nan2008")
         IsNan2008 = false;
@@ -381,6 +385,11 @@ class LLVM_LIBRARY_VISIBILITY MipsTargetInfo : public TargetInfo {
     if (StrictAlign)
       HasUnalignedAccess = false;
 
+    if (HasMSA && !FpGiven) {
+      FPMode = FP64;
+      Features.push_back("+fp64");
+    }
+
     setDataLayout();
 
     return true;