The ability to use vector initializer lists is a GNU vector extension

and is unrelated to the NEON intrinsics in arm_neon.h. On little
endian machines it works fine, however on big endian machines it
exhibits surprising behaviour:

    uint32x2_t x = {42, 64};
    return vget_lane_u32(x, 0); // Will return 64.

Because of this, explicitly call out that it is unsupported on big
endian machines.

This patch will emit the following warning in big-endian mode:

    test.c:3:15: warning: vector initializers are a GNU extension and are not compatible with NEON intrinsics [-Wgnu]
    int32x4_t x = {0, 1, 2, 3};
                  ^
    test.c:3:15: note: consider using vld1q_s32() to initialize a vector from memory, or vcombine_s32(vcreate_s32(), vcreate_s32()) to initialize from integer constants
    1 warning generated.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@211362 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 10 insertions, 0 deletions

diff --git a/include/clang/Basic/DiagnosticSemaKinds.td b/include/clang/Basic/DiagnosticSemaKinds.td
index e6c8b9a34b..f7f08fc4cb 100644
--- a/include/clang/Basic/DiagnosticSemaKinds.td
+++ b/include/clang/Basic/DiagnosticSemaKinds.td
@@ -6729,6 +6729,16 @@ def err_invalid_neon_type_code : Error<
   "incompatible constant for this __builtin_neon function">; 
 def err_argument_invalid_range : Error<
   "argument should be a value from %0 to %1">;
+def warn_neon_vector_initializer_non_portable : Warning<
+  "vector initializers are not compatible with NEON intrinsics in big endian "
+  "mode">, InGroup<DiagGroup<"nonportable-vector-initialization">>;
+def note_neon_vector_initializer_non_portable : Note<
+  "consider using vld1_%0%1() to initialize a vector from memory, or "
+  "vcreate_%0%1() to initialize from an integer constant">;
+def note_neon_vector_initializer_non_portable_q : Note<
+  "consider using vld1q_%0%1() to initialize a vector from memory, or "
+  "vcombine_%0%1(vcreate_%0%1(), vcreate_%0%1()) to initialize from integer "
+  "constants">;
 
 def err_builtin_longjmp_invalid_val : Error<
   "argument to __builtin_longjmp must be a constant 1">;