[SYCL] Put constant initializer list data in non-generic addr space. (intel#3005)

* [SYCL] Put constant initializer list data in non-generic addr space.

Big constant initializer lists (>= 16 elements) were represented as a
global in the generic address space. This is incorrect, as this is an
alias AS, and allocation is not possible in it - compiler will have no
clue where to really put data. Gen vector BE crashed on this pattern.
The fix is to put this data into the same address space as a string
literal.

Signed-off-by: Konstantin S Bobrovsky <[email protected]>

Author: kbobrovs

clang/lib/CodeGen/CGExprAgg.cpp

@@ -499,6 +499,12 @@ void AggExprEmitter::EmitArrayInit(Address DestPtr, llvm::ArrayType *AType,
     CodeGen::CodeGenModule &CGM = CGF.CGM;
     ConstantEmitter Emitter(CGF);
     LangAS AS = ArrayQTy.getAddressSpace();
+    if (CGM.getLangOpts().SYCLIsDevice && AS == LangAS::Default) {
+      // SYCL's default AS is 'generic', which can't be used to define constant
+      // initializer data in. It is reasonable to keep it in the same AS
+      // as string literals.
+      AS = CGM.getStringLiteralAddressSpace();
+    }
     if (llvm::Constant *C = Emitter.tryEmitForInitializer(E, AS, ArrayQTy)) {
       auto GV = new llvm::GlobalVariable(
           CGM.getModule(), C->getType(),

clang/test/CodeGenSYCL/local_var_big_init_as.cpp

@@ -0,0 +1,30 @@
+// RUN: %clang_cc1 -fsycl -fsycl-is-device -triple spir64-unknown-unknown-sycldevice \
+// RUN: -emit-llvm -o - %s | FileCheck %s
+
+// This test checks that data for big constant initializer lists is placed
+// into the global address space by the SYCL compiler.
+
+struct Test {
+  Test() : set{
+               0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15,
+               0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15} {};
+  int set[32];
+};
+// CHECK-DAG: @constinit = private unnamed_addr addrspace(1) constant
+// CHECK: [32 x i32]
+// CHECK: [i32 0, i32 1, i32 2, i32 3, i32 4, i32 5, i32 6, i32 7,
+// CHECK:  i32 8, i32 9, i32 10, i32 11, i32 12, i32 13, i32 14, i32 15,
+// CHECK:  i32 0, i32 1, i32 2, i32 3, i32 4, i32 5, i32 6, i32 7,
+// CHECK:  i32 8, i32 9, i32 10, i32 11, i32 12, i32 13, i32 14, i32 15
+// CHECK: ], align 4
+// CHECK-NOT: @constinit = private unnamed_addr addrspace(0)
+// CHECK-NOT: @constinit = private unnamed_addr addrspace(2)
+// CHECK-NOT: @constinit = private unnamed_addr addrspace(3)
+// CHECK-NOT: @constinit = private unnamed_addr addrspace(4)
+
+__attribute__((sycl_device)) void bar(Test &x);
+
+__attribute__((sycl_device)) void zoo() {
+  Test mc;
+  bar(mc);
+}