Add possibility to disable ShrinkArrayAlloca

Add a registry key and a compilation option to disable ShrinkArrayAlloca
pass.

Author: mmerecki

IGC/Compiler/CISACodeGen/ShaderCodeGen.cpp

@@ -1661,7 +1661,11 @@ void OptimizeIR(CodeGenContext* const pContext)
             mpm.add(llvm::createEarlyCSEPass());
             if (pContext->m_instrTypes.hasNonPrimitiveAlloca)
             {
-                mpm.add(new ShrinkArrayAllocaPass());
+                if( pContext->getModuleMetaData()->compOpt.DisableShrinkArrayAllocaPass == false &&
+                    IGC_IS_FLAG_DISABLED(DisableShrinkArrayAllocaPass))
+                {
+                    mpm.add(new ShrinkArrayAllocaPass());
+                }
                 // run custom safe opts to potentially get rid of indirect
                 // addressing of private arrays, see visitLoadInst
                 mpm.add(new CustomSafeOptPass());

IGC/common/MDFrameWork.h

@@ -455,6 +455,7 @@ namespace IGC
         bool ForceLinearWalkOnLinearUAV                 = false;
         bool DisableLscSamplerRouting                   = false;
         bool UseBarrierControlFlowOptimization          = false;
+        bool DisableShrinkArrayAllocaPass               = false;
     };
 
     enum class ThreadIDLayout

IGC/common/igc_flags.h

@@ -534,6 +534,7 @@ DECLARE_IGC_REGKEY(DWORD, EnableMeshSLMCache,           0,     "Enables caching
                                                                 bit3 - mirror mode, if this bit is set bits 0, 1 and 2 are ignored, \
                                                                        enable caching of outputs that are read in the shader\
                                                                        data is only mirrored in SLM", true)
+DECLARE_IGC_REGKEY(bool, DisableShrinkArrayAllocaPass,  false, "Disables ShrinkArrayAllocaPass", true)
 DECLARE_IGC_REGKEY(bool, EnableL3FlushForGlobal,        false, "Enable/disable flushing L3 cache for globals", false)
 DECLARE_IGC_REGKEY(bool, EnableCPSOmaskWA,              true,  "Enable workaround for oMask with CPS", false)
 DECLARE_IGC_REGKEY(bool, EnableCPSMSAAOMaskWA,          false, "Enable WA which forces rt writes to happen at pixel rate when cps, msaa, and omask are present.", true)