Allow mem2reg when -cl-opt-disable is passed

Change-Id: I763a93e851085be3d8f10f65546a2a9178c79247

Author: pratikashar

IGC/Compiler/CISACodeGen/ShaderCodeGen.cpp

@@ -449,6 +449,11 @@ inline void AddLegalizationPasses(CodeGenContext &ctx, IGCPassManager& mpm)
         }
         mpm.add(createPromoteMemoryToRegisterPass());
     }
+    else
+    {
+        if(IGC_IS_FLAG_ENABLED(AllowMem2Reg))
+            mpm.add(createPromoteMemoryToRegisterPass());
+    }
     if(ctx.m_instrTypes.hasLoop)
     {
         // need to run loop simplify to canonicalize loop and merge latches

IGC/Compiler/Optimizer/OpenCLPasses/DeviceEnqueueFuncs/TransformBlocks.cpp

@@ -1307,14 +1307,13 @@ namespace //Anonymous
 
             // Run mem2reg pass to make the processing simpler
             bool isOptDisabled = modMD->compOpt.OptDisable;
-            if (!isOptDisabled)
+            if (!isOptDisabled || IGC_IS_FLAG_ENABLED(AllowMem2Reg))
             {
                 legacy::PassManager PM;
                 PM.add(createPromoteMemoryToRegisterPass());
                 changed = PM.run(M) || changed;
             }
 
-
             // calls to blocks (not enqueues) are implemented as indirect calls
             // these calls should be resolved now because indirect calls are not
             // supported by other passes

IGC/common/igc_flags.def

@@ -61,6 +61,7 @@ DECLARE_IGC_REGKEY(bool, EnableAtomicFusion,            false, "To enable/disabl
 DECLARE_IGC_REGKEY(bool, Use16ByteBindlessSampler,      false, "True if 16-byte aligned bindless sampler state is used")
 
 DECLARE_IGC_GROUP("IGC Optimization")
+DECLARE_IGC_REGKEY(bool, AllowMem2Reg,                  false, "Setting this to true makes IGC run mem2reg even when optimizations are disabled")
 DECLARE_IGC_REGKEY(bool, DisableIGCOptimizations,       false, "Setting this to 1/true adds a compiler switch to disables all the above IGC optimizations")
 DECLARE_IGC_REGKEY(bool, DisableLLVMGenericOptimizations, false, "Disable LLVM generic optimization passes")
 DECLARE_IGC_REGKEY(bool, DisableCodeSinking,            false, "Setting this to 1/true adds a compiler switch to disable code-sinking")