[mlir] Use the same pipeline tuning options as clang for execution engine This change make sure that ExecutionEngine's pass pipeline is identical to one used by clang. Previously, SLPVectorization was not enabled which caused differences in code...

[shabalin]

Summary

...generation.

mlir/lib/ExecutionEngine/OptUtils.cpp

if (!ol) {
               .str(),
           inconvertibleErrorCode());
     }
     LoopAnalysisManager lam;
     FunctionAnalysisManager fam;
     CGSCCAnalysisManager cgam;
     ModuleAnalysisManager mam;
 
-    PassBuilder pb(targetMachine);
+    PipelineTuningOptions tuningOptions;
+    tuningOptions.LoopUnrolling = true;
+    tuningOptions.LoopInterleaving = true;
+    tuningOptions.LoopVectorization = true;
+    tuningOptions.SLPVectorization = true;
+
+    PassBuilder pb(targetMachine, tuningOptions);
 
     pb.registerModuleAnalyses(mam);
     pb.registerCGSCCAnalyses(cgam);
     pb.registerFunctionAnalyses(fam);
     pb.registerLoopAnalyses(lam);
     pb.crossRegisterProxies(lam, fam, cgam, mam);
 
     ModulePassManager mpm;