<div dir="ltr">Maybe we should teach Clang not to warn on shadowing if the declaration and all its uses come from the same macro expansion?</div><div class="gmail_extra"><br><br><div class="gmail_quote">On Mon, Oct 7, 2013 at 4:51 PM, Ted Kremenek <span dir="ltr"><<a href="mailto:kremenek@apple.com" target="_blank">kremenek@apple.com</a>></span> wrote:<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">Author: kremenek<br>
Date: Mon Oct 7 18:51:11 2013<br>
New Revision: 192143<br>
<br>
URL: <a href="http://llvm.org/viewvc/llvm-project?rev=192143&view=rev" target="_blank">http://llvm.org/viewvc/llvm-project?rev=192143&view=rev</a><br>
Log:<br>
Suppress useless -Wshadow warning when using _mm* macros from emmintrin.h<br>
<br>
Fixes <rdar://problem/10679282>.<br>
<br>
I'm not completely satisfied with this patch. Sprinkling "diagnostic ignored"<br>
_Pragmas throughout this file is gross, but I couldn't suppress<br>
it for the entire file.<br>
<br>
Modified:<br>
cfe/trunk/lib/Headers/emmintrin.h<br>
cfe/trunk/test/Sema/warn-shadow.c<br>
<br>
Modified: cfe/trunk/lib/Headers/emmintrin.h<br>
URL: <a href="http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Headers/emmintrin.h?rev=192143&r1=192142&r2=192143&view=diff" target="_blank">http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Headers/emmintrin.h?rev=192143&r1=192142&r2=192143&view=diff</a><br>
==============================================================================<br>
--- cfe/trunk/lib/Headers/emmintrin.h (original)<br>
+++ cfe/trunk/lib/Headers/emmintrin.h Mon Oct 7 18:51:11 2013<br>
@@ -826,7 +826,9 @@ _mm_xor_si128(__m128i __a, __m128i __b)<br>
}<br>
<br>
#define _mm_slli_si128(a, count) __extension__ ({ \<br>
+ _Pragma("clang diagnostic push") _Pragma("clang diagnostic ignored \"-Wshadow\""); \<br>
__m128i __a = (a); \<br>
+ _Pragma("clang diagnostic pop"); \<br>
(__m128i)__builtin_ia32_pslldqi128(__a, (count)*8); })<br>
<br>
static __inline__ __m128i __attribute__((__always_inline__, __nodebug__))<br>
@@ -891,7 +893,9 @@ _mm_sra_epi32(__m128i __a, __m128i __cou<br>
<br>
<br>
#define _mm_srli_si128(a, count) __extension__ ({ \<br>
+ _Pragma("clang diagnostic push") _Pragma("clang diagnostic ignored \"-Wshadow\""); \<br>
__m128i __a = (a); \<br>
+ _Pragma("clang diagnostic pop"); \<br>
(__m128i)__builtin_ia32_psrldqi128(__a, (count)*8); })<br>
<br>
static __inline__ __m128i __attribute__((__always_inline__, __nodebug__))<br>
@@ -1280,20 +1284,26 @@ _mm_movemask_epi8(__m128i __a)<br>
}<br>
<br>
#define _mm_shuffle_epi32(a, imm) __extension__ ({ \<br>
+ _Pragma("clang diagnostic push") _Pragma("clang diagnostic ignored \"-Wshadow\""); \<br>
__m128i __a = (a); \<br>
+ _Pragma("clang diagnostic pop"); \<br>
(__m128i)__builtin_shufflevector((__v4si)__a, (__v4si) _mm_set1_epi32(0), \<br>
(imm) & 0x3, ((imm) & 0xc) >> 2, \<br>
((imm) & 0x30) >> 4, ((imm) & 0xc0) >> 6); })<br>
<br>
#define _mm_shufflelo_epi16(a, imm) __extension__ ({ \<br>
+ _Pragma("clang diagnostic push") _Pragma("clang diagnostic ignored \"-Wshadow\""); \<br>
__m128i __a = (a); \<br>
+ _Pragma("clang diagnostic pop"); \<br>
(__m128i)__builtin_shufflevector((__v8hi)__a, (__v8hi) _mm_set1_epi16(0), \<br>
(imm) & 0x3, ((imm) & 0xc) >> 2, \<br>
((imm) & 0x30) >> 4, ((imm) & 0xc0) >> 6, \<br>
4, 5, 6, 7); })<br>
<br>
#define _mm_shufflehi_epi16(a, imm) __extension__ ({ \<br>
+ _Pragma("clang diagnostic push") _Pragma("clang diagnostic ignored \"-Wshadow\""); \<br>
__m128i __a = (a); \<br>
+ _Pragma("clang diagnostic pop"); \<br>
(__m128i)__builtin_shufflevector((__v8hi)__a, (__v8hi) _mm_set1_epi16(0), \<br>
0, 1, 2, 3, \<br>
4 + (((imm) & 0x03) >> 0), \<br>
@@ -1386,8 +1396,10 @@ _mm_movemask_pd(__m128d __a)<br>
}<br>
<br>
#define _mm_shuffle_pd(a, b, i) __extension__ ({ \<br>
+ _Pragma("clang diagnostic push") _Pragma("clang diagnostic ignored \"-Wshadow\""); \<br>
__m128d __a = (a); \<br>
__m128d __b = (b); \<br>
+ _Pragma("clang diagnostic pop"); \<br>
__builtin_shufflevector(__a, __b, (i) & 1, (((i) & 2) >> 1) + 2); })<br>
<br>
static __inline__ __m128 __attribute__((__always_inline__, __nodebug__))<br>
<br>
Modified: cfe/trunk/test/Sema/warn-shadow.c<br>
URL: <a href="http://llvm.org/viewvc/llvm-project/cfe/trunk/test/Sema/warn-shadow.c?rev=192143&r1=192142&r2=192143&view=diff" target="_blank">http://llvm.org/viewvc/llvm-project/cfe/trunk/test/Sema/warn-shadow.c?rev=192143&r1=192142&r2=192143&view=diff</a><br>
==============================================================================<br>
--- cfe/trunk/test/Sema/warn-shadow.c (original)<br>
+++ cfe/trunk/test/Sema/warn-shadow.c Mon Oct 7 18:51:11 2013<br>
@@ -1,5 +1,7 @@<br>
// RUN: %clang_cc1 -verify -fsyntax-only -fblocks -Wshadow %s<br>
<br>
+#include <emmintrin.h><br>
+<br>
int i; // expected-note 3 {{previous declaration is here}}<br>
<br>
void foo() {<br>
@@ -59,3 +61,11 @@ void rdar8883302() {<br>
void test8() {<br>
int bob; // expected-warning {{declaration shadows a variable in the global scope}}<br>
}<br>
+<br>
+// Test that using two macros from emmintrin do not cause a<br>
+// useless -Wshadow warning.<br>
+void rdar10679282() {<br>
+ __m128i qf = _mm_setzero_si128();<br>
+ qf = _mm_slli_si128(_mm_add_epi64(qf, _mm_srli_si128(qf, 8)), 8); // no-warning<br>
+ (void) qf;<br>
+}<br>
<br>
<br>
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</blockquote></div><br></div>