Make it easier to turn off SIMD support (#770)

* make it easier for other projects to turn on ASAN * add AVX2 and AVX512 CMake options * build AFX2 and AFX512F in GitHub * unittest for getSIMDInstructionSet() * enable AVX2 by default, it's from 2013 * Allow SIMD supoprt to be turned off; enable it based on compiler macros
mdaus · Feb 14, 2024 · 463cb15 · 463cb15
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commit 463cb15
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diff --git a/.github/workflows/build_unittest.yml b/.github/workflows/build_unittest.yml
@@ -58,7 +58,7 @@ jobs:
         os: [windows-latest]
         platform: [x64]
         configuration: [Debug] # Debug turns on more compiler warnings
-        avx: [AVX2, AVX512F]
+        avx: [AVX512F]
     name: ${{ matrix.os }}-${{ matrix.avx }}-msbuild
     runs-on: ${{ matrix.os }}
 
@@ -132,7 +132,7 @@ jobs:
       matrix:
         os: [ubuntu-latest]
         configuration: [Debug, Release]
-        avx: [AVX2, AVX512F]
+        avx: [AVX512F]
     name: ${{ matrix.os }}-${{ matrix.configuration }}-${{ matrix.avx }}-CMake
     runs-on: ${{ matrix.os }}
     steps:

diff --git a/modules/c++/avx/unittests/test_m256.cpp b/modules/c++/avx/unittests/test_m256.cpp
@@ -56,20 +56,24 @@ TEST_CASE(test_getSIMDInstructionSet)
 {
     // This is the reverse of getSIMDInstructionSet(): it uses the macros to generate a value.
     constexpr auto simdInstructionSet = sys::getSIMDInstructionSet();
-    #if __AVX512F__
-    static_assert(simdInstructionSet == sys::SIMDInstructionSet::AVX512F, "getSIMDInstructionSet()");
-    #elif __AVX2__
-    static_assert(simdInstructionSet == sys::SIMDInstructionSet::AVX2, "getSIMDInstructionSet()");
+    #if CODA_OSS_ENABLE_SIMD
+        #if __AVX512F__
+        static_assert(simdInstructionSet == sys::SIMDInstructionSet::AVX512F, "getSIMDInstructionSet()");
+        #elif __AVX2__
+        static_assert(simdInstructionSet == sys::SIMDInstructionSet::AVX2, "getSIMDInstructionSet()");
+        #else
+        static_assert(simdInstructionSet == sys::SIMDInstructionSet::SSE2, "getSIMDInstructionSet()");
+        #endif
     #else
-    static_assert(simdInstructionSet == sys::SIMDInstructionSet::SSE2, "getSIMDInstructionSet()");
-    #endif
+        static_assert(simdInstructionSet == sys::SIMDInstructionSet::Disabled, "getSIMDInstructionSet()");
+    #endif // CODA_OSS_ENABLE_SIMD
 
     CODA_OSS_disable_warning_push
     #if _MSC_VER
     #pragma warning(disable: 4127) // conditional expression is constant
     #endif
 
-    switch (sys::getSIMDInstructionSet()) // run-time value
+    switch (sys::getSIMDInstructionSet()) // run-time value (well, not really, but it could be)
     {
     case sys::SIMDInstructionSet::SSE2:
     {
@@ -86,6 +90,16 @@ TEST_CASE(test_getSIMDInstructionSet)
         TEST_ASSERT(simdInstructionSet == sys::SIMDInstructionSet::AVX512F);
         break;
     }
+    case sys::SIMDInstructionSet::Disabled:
+    {
+        TEST_ASSERT(simdInstructionSet == sys::SIMDInstructionSet::Disabled);
+        break;
+    }
+    case sys::SIMDInstructionSet::Unknown:
+    {
+        TEST_ASSERT(simdInstructionSet == sys::SIMDInstructionSet::Unknown);
+        break;
+    }
     default:
     {
         TEST_FAIL;

diff --git a/modules/c++/sys/include/sys/AbstractOS.h b/modules/c++/sys/include/sys/AbstractOS.h
@@ -55,27 +55,57 @@ namespace sys
  *  Also see https://gcc.gnu.org/onlinedocs/gcc/x86-Options.html
  *  "... For the x86-64 compiler, these extensions [ -msse2 ] are enabled by default."
 *   We're 64-bit only.
+* 
+* Well ... it turns out third parties want to compile this code in different
+* enviroments which we don't know about; SIMD support makes that
+* more difficult.
  */
+#ifdef CODA_OSS_DISABLE_SIMD
+    #ifdef CODA_OSS_ENABLE_SIMD
+        #error "CODA_OSS_ENABLE_SIMD already #define'd'"
+    #endif
+    #define CODA_OSS_ENABLE_SIMD 0
+#endif // CODA_OSS_DISABLE_SIMD
+
+#ifndef CODA_OSS_ENABLE_SIMD
+    #if __AVX512F__ || __AVX2__
+        #define CODA_OSS_ENABLE_SIMD 1
+    #elif _MSC_VER && _M_X64 /*MSVC for SSE2*/ 
+        #define CODA_OSS_ENABLE_SIMD 1
+    #elif __GNUC__ && __SSE2__
+        #define CODA_OSS_ENABLE_SIMD 1
+    #else
+        #define CODA_OSS_ENABLE_SIMD 0
+    #endif
+#endif
+
 enum class SIMDInstructionSet
 {
+    Disabled, // CODA_OSS_ENABLE_SIMD = 0
+    Unknown, // CODA_OSS_ENABLE_SIMD = 1, but can't determine
+
     SSE2, //  https://en.wikipedia.org/wiki/SSE2
     AVX2,  // https://en.wikipedia.org/wiki/Advanced_Vector_Extensions
     AVX512F, // https://en.wikipedia.org/wiki/AVX-512
 };
 
-constexpr auto getSIMDInstructionSet() { return SIMDInstructionSet::
-    // https://learn.microsoft.com/en-us/cpp/preprocessor/predefined-macros?view=msvc-170
-
-    #if __AVX512F__
-            AVX512F
-    #elif __AVX2__
-            AVX2
-    #elif _M_X64 /*MSVC*/ || __SSE2__ /*GCC*/
-            SSE2
+constexpr auto getSIMDInstructionSet() { 
+    #if !CODA_OSS_ENABLE_SIMD
+        return SIMDInstructionSet::Disabled;
     #else
-        #error "Can't determine SIMDInstructionSet'"
-    #endif
-; }
+        // https://learn.microsoft.com/en-us/cpp/preprocessor/predefined-macros?view=msvc-170
+        #if __AVX512F__
+            return SIMDInstructionSet::AVX512F;
+        #elif __AVX2__
+            return SIMDInstructionSet::AVX2;
+        #elif _M_X64 /*MSVC*/ || __SSE2__ /*GCC*/
+            return SIMDInstructionSet::SSE2;
+        #else
+            #error "Can't determine SIMDInstructionSet'"
+            return SIMDInstructionSet::Unknown;
+        #endif
+    #endif // CODA_OSS_ENABLE_SIMD
+}
 
 /*!
  *  \class AbstractOS