indirect access detection - bugfix for divergent paths

Fixes bug in indirect access detection for divergent paths.

Author: pkwasnie-intel

IGC/AdaptorOCL/ocl_igc_shared/indirect_access_detection/version.h

@@ -13,4 +13,4 @@ SPDX-License-Identifier: MIT
 
 #pragma once
 
-const uint32_t INDIRECT_ACCESS_DETECTION_VERSION = 8;
+const uint32_t INDIRECT_ACCESS_DETECTION_VERSION = 9;

IGC/Compiler/Optimizer/OpenCLPasses/ScalarArgAsPointer/ScalarArgAsPointer.cpp

@@ -224,11 +224,12 @@ ScalarArgAsPointerAnalysis::findArgs(llvm::Instruction* inst)
         {
             auto args = analyzeOperand(inst->getOperand(i));
 
-            if (!args)
-                return nullptr; // propagate fail
-
-            result->insert(args->begin(), args->end());
+            if (args)
+                result->insert(args->begin(), args->end());
         }
+
+        if (result->empty())
+            return nullptr; // propagate fail
     }
 
     m_visitedInst[inst] = result;

IGC/Compiler/tests/ScalarArgAsPointer/add.ll

@@ -0,0 +1,27 @@
+;=========================== begin_copyright_notice ============================
+;
+; Copyright (C) 2024 Intel Corporation
+;
+; SPDX-License-Identifier: MIT
+;
+;============================ end_copyright_notice =============================
+
+; REQUIRES: llvm-14-plus
+; RUN: igc_opt --opaque-pointers --igc-scalar-arg-as-pointer-analysis -igc-serialize-metadata -S %s | FileCheck %s
+;
+; CHECK: !{!"m_OpenCLArgScalarAsPointersSet{{[[][0-9][]]}}", i32 0}
+
+define spir_kernel void @test(i64 %a) #0 {
+entry:
+  %0 = add nsw i64 1, 2
+  %1 = add nsw i64 %a, %0
+  %2 = inttoptr i64 %1 to i32 addrspace(1)*
+  store i32 39, i32 addrspace(1)* %2, align 4
+  ret void
+}
+
+!igc.functions = !{!0}
+
+!0 = !{void (i64)* @test, !1}
+!1 = !{!2}
+!2 = !{!"function_type", i32 0}

IGC/Compiler/tests/ScalarArgAsPointer/gep.ll

@@ -0,0 +1,27 @@
+;=========================== begin_copyright_notice ============================
+;
+; Copyright (C) 2024 Intel Corporation
+;
+; SPDX-License-Identifier: MIT
+;
+;============================ end_copyright_notice =============================
+
+; REQUIRES: llvm-14-plus
+; RUN: igc_opt --opaque-pointers --igc-scalar-arg-as-pointer-analysis -igc-serialize-metadata -S %s | FileCheck %s
+;
+; CHECK-NOT: m_OpenCLArgScalarAsPointersSet
+
+define spir_kernel void @test(i64 %a, i32 addrspace(1)* %p) #0 {
+entry:
+  %0 = add nsw i64 1, 2
+  %1 = add nsw i64 %a, %0
+  %2 = getelementptr inbounds i32, i32 addrspace(1)* %p, i64 %1
+  store i32 39, i32 addrspace(1)* %2, align 4
+  ret void
+}
+
+!igc.functions = !{!0}
+
+!0 = !{void (i64, i32 addrspace(1)*)* @test, !1}
+!1 = !{!2}
+!2 = !{!"function_type", i32 0}

IGC/Compiler/tests/ScalarArgAsPointer/phi.ll

@@ -0,0 +1,39 @@
+;=========================== begin_copyright_notice ============================
+;
+; Copyright (C) 2024 Intel Corporation
+;
+; SPDX-License-Identifier: MIT
+;
+;============================ end_copyright_notice =============================
+
+; REQUIRES: llvm-14-plus
+; RUN: igc_opt --opaque-pointers --igc-scalar-arg-as-pointer-analysis -igc-serialize-metadata -S %s | FileCheck %s
+;
+; Tests "phi" instruction, when first path leads to scalar as pointer.
+;
+; CHECK-NOT: !{!"m_OpenCLArgScalarAsPointersSet{{[[][0-9][]]}}", i32 0}
+; CHECK:     !{!"m_OpenCLArgScalarAsPointersSet{{[[][0-9][]]}}", i32 1}
+; CHECK-NOT: !{!"m_OpenCLArgScalarAsPointersSet{{[[][0-9][]]}}", i32 2}
+
+define spir_kernel void @test(i1 %s, i64 %a, i32 addrspace(1)* %b) #0 {
+entry:
+  br i1 %s, label %if.then, label %if.else
+
+if.then:
+  %0 = inttoptr i64 %a to i32 addrspace(1)*
+  br label %if.end
+
+if.else:
+  br label %if.end
+
+if.end:
+  %1 = phi i32 addrspace(1)* [ %0, %if.then ], [ %b, %if.else ]
+  store i32 39, i32 addrspace(1)* %1, align 4
+  ret void
+}
+
+!igc.functions = !{!0}
+
+!0 = !{void (i1, i64, i32 addrspace(1)*)* @test, !1}
+!1 = !{!2}
+!2 = !{!"function_type", i32 0}