[llvm-opt-fuzzer] Add couple of popular passes

[igor-laevsky]

Summary

I think it's time to extend passes covered by the llvm-opt-fuzzer. As a first batch I have chosen couple of the most popular non-loop passes.

[bogner]

No complaints here. One minor question about the implementation.

lib/FuzzMutate/FuzzerCLI.cpp

87–88

Maybe we've already gone over this, but why is this startswith() rather than equals()?

[igor-laevsky]

lib/FuzzMutate/FuzzerCLI.cpp

87–88

Actually, no good reason, need to fix that :) Thanks!

lib/FuzzMutate/FuzzerCLI.cpp

void llvm::handleExecNameEncodedOptimizerOpts(StringRef ExecName) {
   if (NameAndArgs.second.empty())
     return;
 
   SmallVector<StringRef, 4> Opts;
   NameAndArgs.second.split(Opts, '-');
   for (StringRef Opt : Opts) {
     if (Opt.startswith("instcombine")) {
       Args.push_back("-passes=instcombine");
+    } else if (Opt.startswith("earlycse")) {
+      Args.push_back("-passes=early-cse");
+    } else if (Opt.startswith("simplifycfg")) {
+      Args.push_back("-passes=simplify-cfg");
+    } else if (Opt.startswith("gvn")) {
+      Args.push_back("-passes=gvn");
+    } else if (Opt.startswith("sccp")) {
+      Args.push_back("-passes=sccp");
     } else if (Triple(Opt).getArch()) {
       Args.push_back("-mtriple=" + Opt.str());
     } else {
       errs() << ExecName << ": Unknown option: " << Opt << ".\n";
       exit(1);
     }
   }