[RISCV] Fix RISCVTargetInfo::initFeatureMap, add non-ISA features back after implication

Previously D113336 makes RISCVTargetInfo::initFeatureMap return the results
processed by RISCVISAInfo, which only consists of ISA features and misses
non-ISA features like `relax` and `save-restore`.

This patch fixes the problem.

Reviewed By: junparser

Differential Revision: https://reviews.llvm.org/D119541

Author: eopXD

clang/lib/Basic/Targets/RISCV.cpp

@@ -232,8 +232,16 @@ bool RISCVTargetInfo::initFeatureMap(
     return false;
   }
 
-  return TargetInfo::initFeatureMap(Features, Diags, CPU,
-                                    (*ParseResult)->toFeatureVector());
+  // RISCVISAInfo makes implications for ISA features
+  std::vector<std::string> ImpliedFeatures = (*ParseResult)->toFeatureVector();
+  // Add non-ISA features like `relax` and `save-restore` back
+  for (std::string Feature : FeaturesVec) {
+    if (std::find(begin(ImpliedFeatures), end(ImpliedFeatures), Feature) ==
+        end(ImpliedFeatures))
+      ImpliedFeatures.push_back(Feature);
+  }
+
+  return TargetInfo::initFeatureMap(Features, Diags, CPU, ImpliedFeatures);
 }
 
 /// Return true if has this feature, need to sync with handleTargetFeatures.

clang/test/Driver/riscv-default-features.c

@@ -0,0 +1,9 @@
+// RUN: %clang -target riscv32-unknown-elf -S -emit-llvm %s -o - | FileCheck %s -check-prefix=RV32
+
+// RV32: "target-features"="+a,+c,+m,+relax,-save-restore"
+// RV64: "target-features"="+64bit,+a,+c,+m,+relax,-save-restore"
+
+// Dummy function
+int foo(){
+  return  3;
+}