Resolve IB_to_private/local builtins from Generic AS

When there is no Local/Private to Generic AS casting it is safe
to replace corresponding builtin call by nullptr.

Author: agrabezh

IGC/Compiler/Optimizer/OpenCLPasses/GenericAddressResolution/StaticGASResolution.cpp

@@ -73,6 +73,34 @@ bool StaticGASResolution::runOnFunction(llvm::Function& F)
                 changed = true;
             }
         }
+
+        // When there is no Private/Local to Generic AS casting it is safe
+        // to replace corresponding builtin calls by nullptr.
+        CallInst* CI = dyn_cast<CallInst>(I);
+        if (CI)
+        {
+            Function* pCalledFunc = CI->getCalledFunction();
+            if (pCalledFunc && (pCalledFunc->getName() == "__builtin_IB_to_private" ||
+                                pCalledFunc->getName() == "__builtin_IB_to_local"))
+            {
+                IGC_ASSERT(IGCLLVM::getNumArgOperands(CI) == 1);
+                Value* arg = CI->getArgOperand(0);
+                PointerType* argType = dyn_cast<PointerType>(arg->getType());
+                IGC_ASSERT(argType != nullptr);
+                PointerType* dstType = dyn_cast<PointerType>(CI->getType());
+                IGC_ASSERT(dstType != nullptr);
+
+                auto argAS = cast<PointerType>(arg->getType())->getAddressSpace();
+                if (argAS == ADDRESS_SPACE_GENERIC)
+                {
+                    Value* newPtr = llvm::ConstantPointerNull::get(dstType);
+                    CI->replaceAllUsesWith(newPtr);
+                    CI->eraseFromParent();
+
+                    changed = true;
+                }
+            }
+        }
     }
 
     return changed;

IGC/Compiler/tests/ResolveGAS/builtin.ll

@@ -0,0 +1,64 @@
+;=========================== begin_copyright_notice ============================
+;
+; Copyright (C) 2024 Intel Corporation
+;
+; SPDX-License-Identifier: MIT
+;
+;============================ end_copyright_notice =============================
+;
+; REQUIRES: llvm-14-plus
+; RUN: igc_opt %s -S -o - -static-gas-resolution | FileCheck %s
+;
+; Checks that StaticGASResolution removes IB_to_private/IB_to_local builtin calls
+; when there is no Private/Local to Generic AS casting
+
+target datalayout = "e-p:64:64:64-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:64:64-f32:32:32-f64:64:64-v16:16:16-v24:32:32-v32:32:32-v48:64:64-v64:64:64-v96:128:128-v128:128:128-v192:256:256-v256:256:256-v512:512:512-v1024:1024:1024-n8:16:32"
+
+define spir_kernel void @test_builtin(i8 addrspace(4)* noundef %p1) {
+; CHECK-LABEL: @test_builtin(
+; CHECK-NEXT:  bb2:
+; CHECK-NOT:     [[CALL1:%.*]] = call spir_func i8 addrspace(3)* @__builtin_IB_to_local(
+; CHECK-NEXT:    [[TOBOOL1:%.*]] = icmp eq i8 addrspace(3)* null, null
+; CHECK-NEXT:    br label [[BB3:%.*]]
+; CHECK:       bb3:
+; CHECK-NOT:     [[CALL2:%.*]] = call spir_func i8* @__builtin_IB_to_private(
+; CHECK-NEXT:    [[TOBOOL2:%.*]] = icmp eq i8* null, null
+; CHECK-NEXT:    ret void
+bb2:
+  %call.i1 = call spir_func i8 addrspace(3)* @__builtin_IB_to_local(i8 addrspace(4)* noundef %p1)
+  %tobool1 = icmp eq i8 addrspace(3)* %call.i1, null
+  br label %bb3
+
+bb3:                                      ; preds = %bb2
+  %call.i2 = call spir_func i8* @__builtin_IB_to_private(i8 addrspace(4)* noundef %p1)
+  %tobool2 = icmp eq i8* %call.i2, null
+  ret void
+}
+
+define spir_kernel void @test_builtin1(i8* noundef %p0) {
+; CHECK-LABEL: @test_builtin1(
+; CHECK-NEXT:  bb2:
+; CHECK-NEXT:    [[P1:%.*]] = addrspacecast i8* [[P0:%.*]] to i8 addrspace(4)*
+; CHECK-NEXT:    [[CALL_I1:%.*]] = call spir_func i8 addrspace(3)* @__builtin_IB_to_local(i8 addrspace(4)* noundef [[P1]])
+; CHECK-NEXT:    [[TOBOOL1:%.*]] = icmp eq i8 addrspace(3)* [[CALL_I1]], null
+; CHECK-NEXT:    br label [[BB3:%.*]]
+; CHECK:       bb3:
+; CHECK-NEXT:    [[CALL_I2:%.*]] = call spir_func i8* @__builtin_IB_to_private(i8 addrspace(4)* noundef [[P1]])
+; CHECK-NEXT:    [[TOBOOL2:%.*]] = icmp eq i8* [[CALL_I2]], null
+; CHECK-NEXT:    ret void
+bb2:
+  %p1 = addrspacecast i8* %p0 to i8 addrspace(4)*
+  %call.i1 = call spir_func i8 addrspace(3)* @__builtin_IB_to_local(i8 addrspace(4)* noundef %p1)
+  %tobool1 = icmp eq i8 addrspace(3)* %call.i1, null
+  br label %bb3
+
+bb3:                                      ; preds = %bb2
+  %call.i2 = call spir_func i8* @__builtin_IB_to_private(i8 addrspace(4)* noundef %p1)
+  %tobool2 = icmp eq i8* %call.i2, null
+  ret void
+}
+
+declare spir_func i8 addrspace(3)* @__builtin_IB_to_local(i8 addrspace(4)*)
+
+declare spir_func i8* @__builtin_IB_to_private(i8 addrspace(4)*)
+