Since clang does not support "#pragma GCC", the instruction sets are
always disabled. In this change, we
1. wrap "#pragma GCC" inside "#ifndef __clang__",
2. only retain them around "#include <{e,i,s}mmintrin.h>" to work
around gcc bug,
3. and annotate each function with `__attribute__((target(*)))` which
is recognized by both gcc and clang.
Signed-off-by: Shu-Chun Weng <s...@google.com>
---
configure | 16 ++++++++++++++--
util/bufferiszero.c | 33 +++++++++++++++++++++++----------
2 files changed, 37 insertions(+), 12 deletions(-)
diff --git a/configure b/configure
index 4bd80ed507..d9ce3aa5db 100755
--- a/configure
+++ b/configure
@@ -5808,10 +5808,16 @@ fi
if test "$cpuid_h" = "yes" && test "$avx2_opt" != "no"; then
cat > $TMPC << EOF
+#include <cpuid.h>
+#ifndef __clang__
#pragma GCC push_options
#pragma GCC target("avx2")
-#include <cpuid.h>
+#endif
#include <immintrin.h>
+#ifndef __clang__
+#pragma GCC pop_options
+#endif
+__attribute__((target("avx2")))
static int bar(void *a) {
__m256i x = *(__m256i *)a;
return _mm256_testz_si256(x, x);
@@ -5835,10 +5841,16 @@ fi
if test "$cpuid_h" = "yes" && test "$avx512f_opt" = "yes"; then
cat > $TMPC << EOF
+#include <cpuid.h>
+#ifndef __clang__
#pragma GCC push_options
#pragma GCC target("avx512f")
-#include <cpuid.h>
+#endif
#include <immintrin.h>
+#ifndef __clang__
+#pragma GCC pop_options
+#endif
+__attribute__((target("avx512f")))
static int bar(void *a) {
__m512i x = *(__m512i *)a;
return _mm512_test_epi64_mask(x, x);
diff --git a/util/bufferiszero.c b/util/bufferiszero.c
index 695bb4ce28..ca836b6e8c 100644
--- a/util/bufferiszero.c
+++ b/util/bufferiszero.c
@@ -64,17 +64,18 @@ buffer_zero_int(const void *buf, size_t len)
}
#if defined(CONFIG_AVX512F_OPT) || defined(CONFIG_AVX2_OPT) ||
defined(__SSE2__)
-/* Do not use push_options pragmas unnecessarily, because clang
- * does not support them.
- */
-#if defined(CONFIG_AVX512F_OPT) || defined(CONFIG_AVX2_OPT)
+#ifndef __clang__
#pragma GCC push_options
#pragma GCC target("sse2")
#endif
#include <emmintrin.h>
+#ifndef __clang__
+#pragma GCC pop_options
+#endif
/* Note that each of these vectorized functions require len >= 64. */
+__attribute__((target("sse2")))
static bool
buffer_zero_sse2(const void *buf, size_t len)
{
@@ -104,19 +105,22 @@ buffer_zero_sse2(const void *buf, size_t len)
return _mm_movemask_epi8(_mm_cmpeq_epi8(t, zero)) == 0xFFFF;
}
-#if defined(CONFIG_AVX512F_OPT) || defined(CONFIG_AVX2_OPT)
-#pragma GCC pop_options
-#endif
#ifdef CONFIG_AVX2_OPT
/* Note that due to restrictions/bugs wrt __builtin functions in gcc <= 4.8,
* the includes have to be within the corresponding push_options region, and
* therefore the regions themselves have to be ordered with increasing ISA.
*/
+#ifndef __clang__
#pragma GCC push_options
#pragma GCC target("sse4")
+#endif
#include <smmintrin.h>
+#ifndef __clang__
+#pragma GCC pop_options
+#endif
+__attribute__((target("sse4")))
static bool
buffer_zero_sse4(const void *buf, size_t len)
{
@@ -145,11 +149,16 @@ buffer_zero_sse4(const void *buf, size_t len)
return _mm_testz_si128(t, t);
}
-#pragma GCC pop_options
+#ifndef __clang__
#pragma GCC push_options
#pragma GCC target("avx2")
+#endif
#include <immintrin.h>
+#ifndef __clang__
+#pragma GCC pop_options
+#endif
+__attribute__((target("avx2")))
static bool
buffer_zero_avx2(const void *buf, size_t len)
{
@@ -176,14 +185,19 @@ buffer_zero_avx2(const void *buf, size_t len)
return _mm256_testz_si256(t, t);
}
-#pragma GCC pop_options
#endif /* CONFIG_AVX2_OPT */
#ifdef CONFIG_AVX512F_OPT
+#ifndef __clang__
#pragma GCC push_options
#pragma GCC target("avx512f")
+#endif
#include <immintrin.h>
+#ifndef __clang__
+#pragma GCC pop_options
+#endif
+__attribute__((target("avx512f")))
static bool
buffer_zero_avx512(const void *buf, size_t len)
{
@@ -210,7 +224,6 @@ buffer_zero_avx512(const void *buf, size_t len)
return !_mm512_test_epi64_mask(t, t);
}
-#pragma GCC pop_options
#endif
--
2.28.0.rc0.105.gf9edc3c819-goog
