Add flag to disable merging allocas of different types

Adds flag for better control of merge alloca pass.
Also disable more aggresive merging as being default.

Author: stefan-il

IGC/AdaptorCommon/RayTracing/MergeAllocas.cpp

@@ -80,6 +80,21 @@ static bool AddNonOverlappingAlloca(AllocaInfo *MergableAlloca,
         return false;
     }
 
+    if (IGC_IS_FLAG_ENABLED(DisableMergingOfAllocasWithDifferentType))
+    {
+        auto* AllocatedType = MergableAlloca->alloca->getAllocatedType();
+        auto* AllocatedTypeNew = NewAlloca->alloca->getAllocatedType();
+        bool IsArray = AllocatedType->isArrayTy()? true : false;
+        bool IsArrayNew = AllocatedTypeNew->isArrayTy()? true : false;
+        bool AreBothArrays = IsArray && IsArrayNew;
+        if (AreBothArrays && AllocatedType->getArrayElementType() != AllocatedTypeNew->getArrayElementType()) {
+            return false;
+        }
+        if (!AreBothArrays && AllocatedType != AllocatedTypeNew) {
+            return false;
+        }
+    }
+
     // Check if we can merge alloca to one of existing non-overlapping allocas.
     for (auto *NonOverlappingAlloca : MergableAlloca->nonOverlapingAllocas) {
         bool added = AddNonOverlappingAlloca(NonOverlappingAlloca, NewAlloca);

IGC/Compiler/tests/PrivateMemoryResolution/MergeAllocas/merge_allocas_arrays_and_regular.ll

@@ -5,7 +5,8 @@
 ; SPDX-License-Identifier: MIT
 ;
 ;============================ end_copyright_notice =============================
-; RUN: igc_opt --igc-merge-allocas --igc-private-mem-resolution -S %s --platformpvc | FileCheck %s
+; REQUIRES: regkeys
+; RUN: igc_opt --regkey DisableMergingOfAllocasWithDifferentType=0 --igc-merge-allocas --igc-private-mem-resolution -S %s --platformpvc | FileCheck %s
 ; ------------------------------------------------
 ; PrivateMemoryResolution
 ; ------------------------------------------------

IGC/Compiler/tests/PrivateMemoryResolution/MergeAllocas/merge_allocas_different_sized_arrays2.ll

@@ -6,7 +6,7 @@
 ;
 ;============================ end_copyright_notice =============================
 ; REQUIRES: regkeys
-; RUN: igc_opt --typed-pointers --regkey DisableMergingOfMultipleAllocasWithOffset=0 --igc-merge-allocas --igc-private-mem-resolution -S %s --platformpvc | FileCheck %s
+; RUN: igc_opt --typed-pointers --regkey DisableMergingOfMultipleAllocasWithOffset=0 --regkey DisableMergingOfAllocasWithDifferentType=0 --igc-merge-allocas --igc-private-mem-resolution -S %s --platformpvc | FileCheck %s
 ; ------------------------------------------------
 ; PrivateMemoryResolution
 ; ------------------------------------------------

IGC/Compiler/tests/PrivateMemoryResolution/MergeAllocas/merge_allocas_different_type_arrays.ll

@@ -5,7 +5,8 @@
 ; SPDX-License-Identifier: MIT
 ;
 ;============================ end_copyright_notice =============================
-; RUN: igc_opt --typed-pointers --igc-merge-allocas --igc-private-mem-resolution -S %s --platformpvc | FileCheck %s
+; REQUIRES: regkeys
+; RUN: igc_opt --typed-pointers --regkey DisableMergingOfAllocasWithDifferentType=0 --igc-merge-allocas --igc-private-mem-resolution -S %s --platformpvc | FileCheck %s
 ; ------------------------------------------------
 ; PrivateMemoryResolution
 ; ------------------------------------------------

IGC/Compiler/tests/PrivateMemoryResolution/MergeAllocas/merge_allocas_simple_types.ll

@@ -5,7 +5,8 @@
 ; SPDX-License-Identifier: MIT
 ;
 ;============================ end_copyright_notice =============================
-; RUN: igc_opt --typed-pointers --igc-merge-allocas --igc-private-mem-resolution -S %s --platformpvc | FileCheck %s
+; REQUIRES: regkeys
+; RUN: igc_opt --typed-pointers --regkey DisableMergingOfAllocasWithDifferentType=0 --igc-merge-allocas --igc-private-mem-resolution -S %s --platformpvc | FileCheck %s
 ; ------------------------------------------------
 ; PrivateMemoryResolution
 ; ------------------------------------------------

IGC/common/igc_flags.h

@@ -992,8 +992,9 @@ DECLARE_IGC_GROUP("Raytracing Options")
     DECLARE_IGC_REGKEY(bool, DisablePrepareLoadsStores, false, "Disable preparation for MemOpt", true)
     DECLARE_IGC_REGKEY(bool, DisableRayTracingConstantCoalescing, false, "Disable coalescing", true)
     DECLARE_IGC_REGKEY(bool, DisableMergeAllocas, true, "Do not merge allocas prior to SplitAsyncPass", false)
-    DECLARE_IGC_REGKEY(bool, DisableMergeAllocasPrivateMemory, false, "Do not merge allocas prior to PrivateMemoryResolution", false)
-    DECLARE_IGC_REGKEY(bool, DisableMergingOfMultipleAllocasWithOffset, true, "Do not merge multiple smaller allocas under one larger one with different offsets.", false)
+    DECLARE_IGC_REGKEY(bool, DisableMergeAllocasPrivateMemory, false, "Do not merge allocas prior to PrivateMemoryResolution", true)
+    DECLARE_IGC_REGKEY(bool, DisableMergingOfMultipleAllocasWithOffset, true, "Do not merge multiple smaller allocas under one larger one with different offsets.", true)
+    DECLARE_IGC_REGKEY(bool, DisableMergingOfAllocasWithDifferentType, true, "Do not merge allocas of different types.", true)
     DECLARE_IGC_REGKEY(DWORD, RayTracingConstantCoalescingMinBlockSize, 4, "Set the minimum load size in # OWords = [1,2,4,8,16].", true)
     DECLARE_IGC_REGKEY(bool, DisableRayTracingOptimizations, false, "Disable RayTracing Optimizations for debugging", true)
     DECLARE_IGC_REGKEY(DWORD, RayTracingCustomTileXDim1D, 0, "X dimension of tile (default: DG2=256, Xe2+=512)", true)