Add a configure-time check for QT_COMPILER_SUPPORTS_SIMD_ALWAYS

This has two main benefits:
 1) introduces a qmake CONFIG we can use in .pro/.pri/.prf files
 2) removes the need to keep an up-to-date list of which compilers
    support the feature

The test is implemented as trying to compile every single SIMD test we
currently have, but without passing the -mXXX option. The reason for
trying all of them is that some people may have modified their mkspecs
to add -mXXX options or -march=XXX, which could enable the particular
feature we tried, resulting in a false positive outcome.

Change-Id: I938b024e38bf4aac9154fffd14f7784dc8d1f020
Reviewed-by: Oswald Buddenhagen <oswald.buddenhagen@qt.io>

2 files changed, 258 insertions, 0 deletions

diff --git a/config.tests/x86_simd/main.cpp b/config.tests/x86_simd/main.cpp
new file mode 100644
index 0000000000..6005f5b023
--- /dev/null
+++ b/config.tests/x86_simd/main.cpp
@@ -0,0 +1,253 @@
+/****************************************************************************
+**
+** Copyright (C) 2017 Intel Corporation.
+** Contact: https://www.qt.io/licensing/
+**
+** This file is part of the QtCore module of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:LGPL$
+** Commercial License Usage
+** Licensees holding valid commercial Qt licenses may use this file in
+** accordance with the commercial license agreement provided with the
+** Software or, alternatively, in accordance with the terms contained in
+** a written agreement between you and The Qt Company. For licensing terms
+** and conditions see https://www.qt.io/terms-conditions. For further
+** information use the contact form at https://www.qt.io/contact-us.
+**
+** GNU Lesser General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU Lesser
+** General Public License version 3 as published by the Free Software
+** Foundation and appearing in the file LICENSE.LGPL3 included in the
+** packaging of this file. Please review the following information to
+** ensure the GNU Lesser General Public License version 3 requirements
+** will be met: https://www.gnu.org/licenses/lgpl-3.0.html.
+**
+** GNU General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU
+** General Public License version 2.0 or (at your option) the GNU General
+** Public license version 3 or any later version approved by the KDE Free
+** Qt Foundation. The licenses are as published by the Free Software
+** Foundation and appearing in the file LICENSE.GPL2 and LICENSE.GPL3
+** included in the packaging of this file. Please review the following
+** information to ensure the GNU General Public License requirements will
+** be met: https://www.gnu.org/licenses/gpl-2.0.html and
+** https://www.gnu.org/licenses/gpl-3.0.html.
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+// All of our supported compilers support <immintrin.h>
+#include <immintrin.h>
+#define T(x)                      (QT_COMPILER_SUPPORTS_ ## x)
+
+#if !defined(__INTEL_COMPILER) && !defined(_MSC_VER)
+/* GCC requires attributes for a function */
+#  define attribute_target(x)     __attribute__((__target__(x)))
+#else
+#  define attribute_target(x)
+#endif
+
+#if T(SSE2)
+attribute_target("sse2") void test_sse2()
+{
+    __m128i a = _mm_setzero_si128();
+    _mm_maskmoveu_si128(a, _mm_setzero_si128(), 0);
+}
+#endif
+
+#if T(SSE3)
+attribute_target("sse3") void test_sse3()
+{
+    __m128d a = _mm_set1_pd(6.28);
+    __m128d b = _mm_set1_pd(3.14);
+    __m128d result = _mm_addsub_pd(a, b);
+    (void) _mm_movedup_pd(result);
+}
+#endif
+
+#if T(SSSE3)
+attribute_target("ssse3") void test_ssse3()
+{
+    __m128i a = _mm_set1_epi32(42);
+    _mm_abs_epi8(a);
+    (void) _mm_sign_epi16(a, _mm_set1_epi32(64));
+}
+#endif
+
+#if T(SSE4_1)
+attribute_target("sse4.1") void test_sse4_1()
+{
+    __m128 a = _mm_setzero_ps();
+    _mm_ceil_ps(a);
+    __m128i result = _mm_mullo_epi32(_mm_set1_epi32(42), _mm_set1_epi32(64));
+    (void)result;
+}
+#endif
+
+#if T(SSE4_2)
+attribute_target("sse4.2") void test_sse4_2()
+{
+    __m128i a = _mm_setzero_si128();
+    __m128i b = _mm_set1_epi32(42);
+    (void) _mm_cmpestrm(a, 16, b, 16, 0);
+}
+#endif
+
+#if T(AESNI)
+attribute_target("aes,sse4.2") void test_aesni()
+{
+    __m128i a = _mm_setzero_si128();
+    __m128i b = _mm_aesenc_si128(a, a);
+    __m128i c = _mm_aesdec_si128(a, b);
+    (void)c;
+}
+#endif
+
+#if T(F16C)
+attribute_target("f16c") void test_f16c()
+{
+    __m128i a = _mm_setzero_si128();
+    __m128 b = _mm_cvtph_ps(a);
+    __m256 b256 = _mm256_cvtph_ps(a);
+    (void) _mm_cvtps_ph(b, 0);
+    (void) _mm256_cvtps_ph(b256, 0);
+}
+#endif
+
+#if T(RDRND)
+attribute_target("rdrnd") int test_rdrnd()
+{
+    unsigned short us;
+    unsigned int ui;
+    if (_rdrand16_step(&us))
+        return 1;
+    if (_rdrand32_step(&ui))
+        return 1;
+#  if defined(__x86_64) || defined(__x86_64__) || defined(__amd64) || defined(_M_X64)
+    unsigned long long ull;
+    if (_rdrand64_step(&ull))
+        return 1;
+#  endif
+}
+#endif
+
+#if T(SHANI)
+attribute_target("sha") void test_shani()
+{
+    __m128i a = _mm_setzero_si128();
+    __m128i b = _mm_sha1rnds4_epu32(a, a, 0);
+    __m128i c = _mm_sha1msg1_epu32(a, b);
+    __m128i d = _mm_sha256msg2_epu32(b, c);
+    (void)d;
+}
+#endif
+
+#if T(AVX)
+attribute_target("avx") void test_avx()
+{
+    __m256d a = _mm256_setzero_pd();
+    __m256d b = _mm256_set1_pd(42.42);
+    (void) _mm256_add_pd(a, b);
+}
+#endif
+
+#if T(AVX2)
+attribute_target("avx2") void test_avx2()
+{
+    _mm256_zeroall();
+    __m256i a = _mm256_setzero_si256();
+    __m256i b = _mm256_and_si256(a, a);
+    (void) _mm256_add_epi8(a, b);
+}
+#endif
+
+#if T(AVX512F)
+attribute_target("avx512f") void test_avx512f(char *ptr)
+{
+    /* AVX512 Foundation */
+    __mmask16 m = ~1;
+    __m512i i;
+    __m512d d;
+    __m512 f;
+    i = _mm512_maskz_loadu_epi32(0, ptr);
+    d = _mm512_loadu_pd((double *)ptr + 64);
+    f = _mm512_loadu_ps((float *)ptr + 128);
+    _mm512_mask_storeu_epi64(ptr, m, i);
+    _mm512_mask_storeu_ps(ptr + 64, m, f);
+    _mm512_mask_storeu_pd(ptr + 128, m, d);
+}
+#endif
+
+#if T(AVX512ER)
+attribute_target("avx512er") void test_avx512er()
+{
+    /* AVX512 Exponential and Reciprocal */
+    __m512 f;
+    f =  _mm512_exp2a23_round_ps(f, 8);
+}
+#endif
+
+#if T(AVX512CD)
+attribute_target("avx512cd") void test_avx512cd()
+{
+    /* AVX512 Conflict Detection */
+    __mmask16 m = ~1;
+    __m512i i;
+    i = _mm512_maskz_conflict_epi32(m, i);
+}
+#endif
+
+#if T(AVX512PF)
+attribute_target("avx512pf") void test_avx512pf(void *ptr)
+{
+    /* AVX512 Prefetch */
+    __m512i i;
+    __mmask16 m = 0xf;
+    _mm512_mask_prefetch_i64scatter_pd(ptr, m, i, 2, 2);
+}
+#endif
+
+#if T(AVX512DQ)
+attribute_target("avx512dq") void test_avx512dq()
+{
+    /* AVX512 Doubleword and Quadword support */
+    __m512i i;
+    __mmask16 m = ~1;
+    m = _mm512_movepi32_mask(i);
+}
+#endif
+
+#if T(AVX512BW)
+attribute_target("avx512bw") void test_avx512bw(char *ptr)
+{
+    /* AVX512 Byte and Word support */
+    __m512i i;
+    __mmask16 m = ~1;
+    i =  _mm512_mask_loadu_epi8(i, m, ptr - 8);
+}
+#endif
+
+#if T(AVX512VL)
+attribute_target("avx512vl") void test_avx512vl(char *ptr)
+{
+    /* AVX512 Vector Length */
+    __mmask16 m = ~1;
+    __m256i i2 = _mm256_maskz_loadu_epi32(0, ptr);
+    _mm256_mask_storeu_epi32(ptr + 1, m, i2);
+}
+#endif
+
+#if T(AVX512IFMA)
+attribute_target("avx512ifma") void test_avx512ifma()
+{
+    /* AVX512 Integer Fused Multiply-Add */
+    __m512i i;
+    i = _mm512_madd52lo_epu64(i, i, i);
+}
+#endif
+
+int main()
+{
+    return 0;
+}
diff --git a/config.tests/x86_simd/x86_simd.pro b/config.tests/x86_simd/x86_simd.pro
new file mode 100644
index 0000000000..52c24c24a8
--- /dev/null
+++ b/config.tests/x86_simd/x86_simd.pro
@@ -0,0 +1,5 @@
+SOURCES = main.cpp
+for (config, SIMD) {
+    uc = $$upper($$config)
+    DEFINES += QT_COMPILER_SUPPORTS_$${uc}
+}