From b7b6d0fc664f974512279a55a07bebbeb0c3b129 Mon Sep 17 00:00:00 2001
From: Yaxun Liu <Yaxun.Liu@amd.com>
Date: Tue, 12 Apr 2016 19:03:49 +0000
Subject: [PATCH] [OpenCL] Handle AddressSpaceConversion when target address
 space does not change.

In codegen different address spaces may be mapped to the same address
space for a target, e.g. in x86/x86-64 all address spaces are mapped
to 0. Therefore AddressSpaceConversion should be translated by
CreatePointerBitCastOrAddrSpaceCast instead of CreateAddrSpaceCast.

Differential Revision: http://reviews.llvm.org/D18713

llvm-svn: 266107
---
 clang/lib/CodeGen/CGExprScalar.cpp                     |  5 ++++-
 clang/test/CodeGenOpenCL/address-spaces-conversions.cl | 18 ++++++++++++++++++
 2 files changed, 22 insertions(+), 1 deletion(-)

diff --git a/clang/lib/CodeGen/CGExprScalar.cpp b/clang/lib/CodeGen/CGExprScalar.cpp
index 76bfc57..1fd79d0 100644
--- a/clang/lib/CodeGen/CGExprScalar.cpp
+++ b/clang/lib/CodeGen/CGExprScalar.cpp
@@ -1411,7 +1411,10 @@ Value *ScalarExprEmitter::VisitCastExpr(CastExpr *CE) {
   }
   case CK_AddressSpaceConversion: {
     Value *Src = Visit(const_cast<Expr*>(E));
-    return Builder.CreateAddrSpaceCast(Src, ConvertType(DestTy));
+    // Since target may map different address spaces in AST to the same address
+    // space, an address space conversion may end up as a bitcast.
+    return Builder.CreatePointerBitCastOrAddrSpaceCast(Src,
+                                                       ConvertType(DestTy));
   }
   case CK_AtomicToNonAtomic:
   case CK_NonAtomicToAtomic:
diff --git a/clang/test/CodeGenOpenCL/address-spaces-conversions.cl b/clang/test/CodeGenOpenCL/address-spaces-conversions.cl
index cdd6b58..a306e00 100644
--- a/clang/test/CodeGenOpenCL/address-spaces-conversions.cl
+++ b/clang/test/CodeGenOpenCL/address-spaces-conversions.cl
@@ -1,4 +1,6 @@
 // RUN: %clang_cc1 %s -triple x86_64-unknown-linux-gnu -O0 -ffake-address-space-map -cl-std=CL2.0 -emit-llvm -o - | FileCheck %s
+// RUN: %clang_cc1 %s -triple x86_64-unknown-linux-gnu -O0 -cl-std=CL2.0 -emit-llvm -o - | FileCheck --check-prefix=CHECK-NOFAKE %s
+// When -ffake-address-space-map is not used, all addr space mapped to 0 for x86_64.
 
 // test that we generate address space casts everywhere we need conversions of
 // pointers to different address spaces
@@ -7,17 +9,33 @@ void test(global int *arg_glob, generic int *arg_gen) {
   int var_priv;
   arg_gen = arg_glob; // implicit cast global -> generic
   // CHECK: %{{[0-9]+}} = addrspacecast i32 addrspace(1)* %{{[0-9]+}} to i32 addrspace(4)*
+  // CHECK-NOFAKE-NOT: addrspacecast
 
   arg_gen = &var_priv; // implicit cast with obtaining adr, private -> generic
   // CHECK: %{{[0-9]+}} = addrspacecast i32* %var_priv to i32 addrspace(4)*
+  // CHECK-NOFAKE-NOT: addrspacecast
+
   arg_glob = (global int *)arg_gen; // explicit cast
   // CHECK: %{{[0-9]+}} = addrspacecast i32 addrspace(4)* %{{[0-9]+}} to i32 addrspace(1)*
+  // CHECK-NOFAKE-NOT: addrspacecast
+
   global int *var_glob =
       (global int *)arg_glob; // explicit cast in the same address space
   // CHECK-NOT: %{{[0-9]+}} = addrspacecast i32 addrspace(1)* %{{[0-9]+}} to i32 addrspace(1)*
+  // CHECK-NOFAKE-NOT: addrspacecast
+
   var_priv = arg_gen - arg_glob; // arithmetic operation
   // CHECK: %{{.*}} = ptrtoint i32 addrspace(4)* %{{.*}} to i64
   // CHECK: %{{.*}} = ptrtoint i32 addrspace(1)* %{{.*}} to i64
+  // CHECK-NOFAKE: %{{.*}} = ptrtoint i32* %{{.*}} to i64
+  // CHECK-NOFAKE: %{{.*}} = ptrtoint i32* %{{.*}} to i64
+
   var_priv = arg_gen > arg_glob; // comparison
   // CHECK: %{{[0-9]+}} = addrspacecast i32 addrspace(1)* %{{[0-9]+}} to i32 addrspace(4)*
+
+  generic void *var_gen_v = arg_glob;
+  // CHECK: addrspacecast
+  // CHECK-NOT: bitcast
+  // CHECK-NOFAKE: bitcast
+  // CHECK-NOFAKE-NOT: addrspacecast
 }
-- 
2.7.4