[Autobackout][FuncReg]Revert of change: 2836dec

 Enable optimization for non-specific api-options

Enable optimizations for options:
-cl-opt-disable and -ze-opt-disable

Author: igorban-intel

IGC/VectorCompiler/lib/Driver/Driver.cpp

@@ -695,8 +695,8 @@ deriveOptimizationLevel(opt::Arg *A, OptSpecifier PrimaryOpt) {
     StringRef Val = A->getValue();
     return parseOptimizationLevelString(Val);
   } else {
-    // Default optimization mode - O2
-    return vc::OptimizerLevel::Full;
+    IGC_ASSERT(A->getOption().matches(OPT_opt_disable_common));
+    return vc::OptimizerLevel::None;
   }
 }
 

IGC/VectorCompiler/lib/GenXCodeGen/GenXLowering.cpp

@@ -4222,13 +4222,13 @@ bool GenXLowering::lowerLzd(Instruction *Inst) {
 bool GenXLowering::lower64Bitreverse(CallInst *CI) {
   // %1 = call i64 @llvm.bitreverse.i64(i64 %in)
   //  to
-  // {%inH, %inL} = rdregion.32 %in
-  // %inRH = bitreverse.32 %inH
-  // %inRL = bitreverse.32 %inL
-  // %res = wrregion.64 {%inRL, %inRH}
+  // %1 = call i64 @llvm.bitreverse.i64(i64 %in)
+  // {inH, inL} = rdregion.32 in
+  // inRH = bitreverse.32 inH
+  // inRL = bitreverse.32 inL
+  // res = wrregion.64 {inRL, inRH}
 
   auto *InType = CI->getType();
-  IGC_ASSERT(InType->getScalarSizeInBits() == 64);
   IRBuilder<> IRB{CI};
   auto Split = IVSplitter(*CI).splitValueLoHi(*CI->getOperand(0));
   auto *ResTy = Split.Lo->getType();