[OpenCL] Prevent generation of globals in non-constant AS for OpenCL.

Avoid using shortcut for const qualified non-constant address space
aggregate variables while generating them on the stack such that
the alloca object is used instead of a global variable containing
initializer.

Review: https://reviews.llvm.org/D27109



git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@288163 91177308-0d34-0410-b5e6-96231b3b80d8

lib/CodeGen/CGDecl.cpp

@@ -948,8 +948,12 @@ CodeGenFunction::EmitAutoVarAlloca(const VarDecl &D) {
       // If the variable's a const type, and it's neither an NRVO
       // candidate nor a __block variable and has no mutable members,
       // emit it as a global instead.
-      if (CGM.getCodeGenOpts().MergeAllConstants && !NRVO && !isByRef &&
-          CGM.isTypeConstant(Ty, true)) {
+      // Exception is if a variable is located in non-constant address space
+      // in OpenCL.
+      if ((!getLangOpts().OpenCL ||
+           Ty.getAddressSpace() == LangAS::opencl_constant) &&
+          (CGM.getCodeGenOpts().MergeAllConstants && !NRVO && !isByRef &&
+           CGM.isTypeConstant(Ty, true))) {
         EmitStaticVarDecl(D, llvm::GlobalValue::InternalLinkage);
 
         // Signal this condition to later callbacks.

test/CodeGenOpenCL/constant-addr-space-globals.cl

-// RUN: %clang_cc1 %s -cl-opt-disable -ffake-address-space-map -emit-llvm -o - | FileCheck %s
+// RUN: %clang_cc1 %s -triple "spir64-unknown-unknown" -cl-opt-disable -ffake-address-space-map -emit-llvm -o - | FileCheck %s
 
 // CHECK: @array = addrspace({{[0-9]+}}) constant
 __constant float array[2] = {0.0f, 1.0f};
@@ -6,3 +6,22 @@ __constant float array[2] = {0.0f, 1.0f};
 kernel void test(global float *out) {
   *out = array[0];
 }
+
+// Test that we don't use directly initializers for const aggregates
+// but create a copy in the original address space (unless a variable itself is
+// in the constant address space).
+
+void foo(constant const int *p1, const int *p2, const int *p3);
+// CHECK: @k.arr1 = internal addrspace(3) constant [3 x i32] [i32 1, i32 2, i32 3]
+// CHECK: @k.arr2 = private unnamed_addr addrspace(3) constant [3 x i32] [i32 4, i32 5, i32 6]
+// CHECK: @k.arr3 = private unnamed_addr addrspace(3) constant [3 x i32] [i32 7, i32 8, i32 9]
+kernel void k(void) {
+  // CHECK-NOT: %arr1 = alloca [3 x i32]
+  constant const int arr1[] = {1, 2, 3};
+  // CHECK: %arr2 = alloca [3 x i32]
+  const int arr2[] = {4, 5, 6};
+  // CHECK: %arr3 = alloca [3 x i32]
+  int arr3[] = {7, 8, 9};
+
+  foo(arr1, arr2, arr3);
+}