Fix MergeAllocas pass not respecting optnone attribute

MergeAllocas pass now correctly skips functions with optnone attribute.

Author: stefan-il

IGC/AdaptorCommon/RayTracing/MergeAllocas.cpp

@@ -332,6 +332,10 @@ void MergeAllocas::getAnalysisUsage(llvm::AnalysisUsage& AU) const
 
 bool MergeAllocas::runOnFunction(Function& F)
 {
+    if (F.hasOptNone()){
+        return false;
+    }
+
     auto ABLA = getAnalysis<AllocationBasedLivenessAnalysis>().getLivenessInfo();
 
     // we group the allocations by type, then sort them into buckets with nonoverlapping liveranges

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

@@ -0,0 +1,24 @@
+;=========================== begin_copyright_notice ============================
+;
+; Copyright (C) 2025 Intel Corporation
+;
+; SPDX-License-Identifier: MIT
+;
+;============================ end_copyright_notice =============================
+; RUN: igc_opt --igc-merge-allocas -S %s --platformpvc | FileCheck %s
+; ------------------------------------------------
+; MergeAllocas
+; ------------------------------------------------
+
+; Check that allocas are not merged if optnone attribute is set
+; Function Attrs: noinline optnone
+define spir_kernel void @_ZTS43Kernel_NoReusePrivMem_SameFunc_AlwaysInline() #0 {
+; CHECK-LABEL: _ZTS43Kernel_NoReusePrivMem_SameFunc_AlwaysInline
+; CHECK-NEXT: alloca [128 x float], i32 0, align 4
+; CHECK-NEXT: alloca [128 x float], i32 0, align 4
+  %1 = alloca [128 x float], i32 0, align 4
+  %2 = alloca [128 x float], i32 0, align 4
+  ret void
+}
+
+attributes #0 = { noinline optnone }