To address review comments and added a test.

Author: DanielCChen

clang/lib/Driver/ToolChains/CommonArgs.cpp

@@ -1252,7 +1252,7 @@ void tools::addArchSpecificRPath(const ToolChain &TC, const ArgList &Args,
                     options::OPT_fno_rtlib_add_rpath, false))
     return;
 
-  if (TC.getTriple().isOSAIX()) // AIX doesn't support -rpath option.
+  if (TC.getTriple().isOSAIX()) // TODO: AIX doesn't support -rpath option.
     return;
 
   SmallVector<std::string> CandidateRPaths(TC.getArchSpecificLibPaths());

flang/test/Driver/flang-ld-powerpc.f90

@@ -23,6 +23,7 @@
 ! AIX64-LD-PER-TARGET-DEFAULT-SAME:     "[[RESOURCE_DIR]]{{/|\\\\}}lib{{/|\\\\}}powerpc64-ibm-aix{{/|\\\\}}libflang_rt.runtime.a"
 ! AIX64-LD-PER-TARGET-DEFAULT-SAME:     "-lm"
 ! AIX64-LD-PER-TARGET-DEFAULT-SAME:     "-lpthread"
+! AIX64-LD-PER-TARGET-DEFAULT-NOT:      "-L/[[RESOURCE_DIR]]{{/|\\\\}}lib{{/|\\\\}}powerpc64-ibm-aix"
 
 
 ! Check powerpc64-ibm-aix 64-bit linking to static flang-rt by option