Revert "Restore lost lto opts for amdgpu" (llvm#1645)

Author: ronlieb

clang/lib/Driver/ToolChains/Clang.cpp

@@ -9460,28 +9460,6 @@ void LinkerWrapper::ConstructJob(Compilation &C, const JobAction &JA,
           A->render(Args, LinkerArgs);
       }
 
-      if (isAMDGPU) {
-        StringRef OOpt;
-        if (const Arg *A = Args.getLastArg(options::OPT_O_Group)) {
-          if (A->getOption().matches(options::OPT_O4) ||
-              A->getOption().matches(options::OPT_Ofast))
-            OOpt = "3";
-          else if (A->getOption().matches(options::OPT_O)) {
-            OOpt = A->getValue();
-            if (OOpt == "g")
-              OOpt = "1";
-            else if (OOpt == "s" || OOpt == "z")
-              OOpt = "2";
-          } else if (A->getOption().matches(options::OPT_O0))
-            OOpt = "0";
-        }
-
-        if (!OOpt.empty() && OOpt != "0") {
-          LinkerArgs.push_back(
-            Args.MakeArgString("--lto-newpm-passes=default<O" + OOpt + ">"));
-        }
-      }
-
       // Forward all of these to the appropriate toolchain.
       for (StringRef Arg : CompilerArgs)
         CmdArgs.push_back(Args.MakeArgString(