cmake: use TargetConditionals.h for SIMD testing on Apple #12731

madebr · 2025-04-03T19:34:38Z

I think include/SDL3/SDL_intrin.h should get a similar makeover.

sezero

Looked OK to be after brief eyeballing.

madebr · 2025-04-03T19:46:59Z

This actions run behaves as expected now: https://github.com/libsdl-org/SDL/actions/runs/14251280259/job/39944568381?pr=12731

it uses -DCMAKE_OSX_ARCHITECTURES=x86_64;arm64
all simd extensions (mmx, sse, avx, neon) are supported, so no #define SDL_DISABLE_xxx's in the generated SDL_build_config.h

madebr · 2025-04-03T19:50:58Z

An Apple person should check whether the SDL_intrin.h behaves as expected.
The header would need this, and perhaps additional changes.

--- a/include/SDL3/SDL_intrin.h
+++ b/include/SDL3/SDL_intrin.h
@@ -356,7 +356,11 @@ _m_prefetch(void *__P)
 # endif
 #endif
 
-#if defined(__x86_64__) || defined(_M_X64) || defined(__i386__) || defined(_M_IX86)
+#ifdef __APPLE__
+#include "TargetConditionals.h"
+#endif
+
+#if defined(__x86_64__) || defined(_M_X64) || defined(__i386__) || defined(_M_IX86) || (defined(TARGET_CPU_X86) && TARGET_CPU_X86) || (defined(TARGET_CPU_X86_64) && TARGET_CPU_X86_64)
 # if ((defined(_MSC_VER) && !defined(_M_X64)) || defined(__MMX__) || defined(SDL_HAS_TARGET_ATTRIBS)) && !defined(SDL_DISABLE_MMX)
 #  define SDL_MMX_INTRINSICS 1
 #  include <mmintrin.h>

sezero · 2025-04-03T19:56:03Z

An Apple person should check whether the SDL_intrin.h behaves as expected. The header would need this, and perhaps additional changes.

--- a/include/SDL3/SDL_intrin.h
+++ b/include/SDL3/SDL_intrin.h
@@ -356,7 +356,11 @@ _m_prefetch(void *__P)
 # endif
 #endif
 
-#if defined(__x86_64__) || defined(_M_X64) || defined(__i386__) || defined(_M_IX86)
+#ifdef __APPLE__
+#include "TargetConditionals.h"
+#endif
+
+#if defined(__x86_64__) || defined(_M_X64) || defined(__i386__) || defined(_M_IX86) || (defined(TARGET_CPU_X86) && TARGET_CPU_X86) || (defined(TARGET_CPU_X86_64) && TARGET_CPU_X86_64)
 # if ((defined(_MSC_VER) && !defined(_M_X64)) || defined(__MMX__) || defined(SDL_HAS_TARGET_ATTRIBS)) && !defined(SDL_DISABLE_MMX)
 #  define SDL_MMX_INTRINSICS 1
 #  include <mmintrin.h>

I don't think this is necessary: TARGET_CPU_X86, for, e.g., is defined to 1 if __i386__ is defined (otherwise to 0). Similarly, TARGET_CPU_X86_64 is defined to 1 if __x86_64__ is defined (otherwise to 0). In short, we are already covering those cases here. Am I missing something?

madebr · 2025-04-03T20:07:49Z

I don't think this is necessary: TARGET_CPU_X86, for, e.g., is defined to 1 if __i386__ is defined (otherwise to 0). Similarly, TARGET_CPU_X86_64 is defined to 1 if __x86_64__ is defined (otherwise to 0). In short, we are already covering those cases here. Am I missing something?

I think we're fine. After thinking about it, CMake was failing because we were including <xmmintrin.h> when targeting arm64.

sezero · 2025-04-03T22:10:44Z

cmake/sdlcompilers.cmake

+    # if test_enabled
+      ${MAIN_BODY}
+    # endif
+      return 0;


If I'm reading this correctly, this x86 test will succeed for aarch64-apple (non-x86.) Similarly, the arm test below will succeed for x86_64-apple (non-arm.) Is this what you really intend?

These functions will only get called if cmake is targeting x64/x86.
I'll add a fail-safe that returns false when the cpu is not x86 (and vice verse for the arm function)

sezero · 2025-08-31T14:36:05Z

This was forgotten??

Patches 1 and 3 are irrelevant here: They should be applied (and cherry-picked to 3.2.x)

As for patch/2 which matters: It needs rebasing. But is the following simpler / more straight-forward for it?

diff --git a/CMakeLists.txt b/CMakeLists.txt
index e7ae6f2..3ce5df9 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -679,6 +679,9 @@ if(SDL_ASSEMBLY)
   set(HAVE_ASSEMBLY TRUE)
 
   if(SDL_MMX)
+   if(APPLE AND SDL_CPU_X64 AND SDL_CPU_ARM64)
+    set(HAVE_MMX TRUE)
+   else()
     cmake_push_check_state()
     if(USE_GCC OR USE_CLANG OR USE_INTELCC)
       string(APPEND CMAKE_REQUIRED_FLAGS " -mmmx")
@@ -698,8 +701,13 @@ if(SDL_ASSEMBLY)
     if(COMPILER_SUPPORTS_MMX)
       set(HAVE_MMX TRUE)
     endif()
+   endif()
   endif()
   if(SDL_SSE)
+   if(APPLE AND SDL_CPU_X64 AND SDL_CPU_ARM64)
+    set(HAVE_SSE TRUE)
+    message("MMX enabled for Apple multi-arch config")
+   else()
     cmake_push_check_state()
     if(USE_GCC OR USE_CLANG OR USE_INTELCC)
       string(APPEND CMAKE_REQUIRED_FLAGS " -msse")
@@ -719,8 +727,13 @@ if(SDL_ASSEMBLY)
     if(COMPILER_SUPPORTS_SSE)
       set(HAVE_SSE TRUE)
     endif()
+   endif()
   endif()
   if(SDL_SSE2)
+   if(APPLE AND SDL_CPU_X64 AND SDL_CPU_ARM64)
+    set(HAVE_SSE2 TRUE)
+    message("SSE2 enabled for Apple multi-arch config")
+   else()
     cmake_push_check_state()
     if(USE_GCC OR USE_CLANG OR USE_INTELCC)
       string(APPEND CMAKE_REQUIRED_FLAGS " -msse2")
@@ -740,8 +753,13 @@ if(SDL_ASSEMBLY)
     if(COMPILER_SUPPORTS_SSE2)
       set(HAVE_SSE2 TRUE)
     endif()
+   endif()
   endif()
   if(SDL_SSE3)
+   if(APPLE AND SDL_CPU_X64 AND SDL_CPU_ARM64)
+    set(HAVE_SSE3 TRUE)
+    message("SSE3 enabled for Apple multi-arch config")
+   else()
     cmake_push_check_state()
     if(USE_GCC OR USE_CLANG OR USE_INTELCC)
       string(APPEND CMAKE_REQUIRED_FLAGS " -msse3")
@@ -762,7 +780,12 @@ if(SDL_ASSEMBLY)
       set(HAVE_SSE3 TRUE)
     endif()
   endif()
+  endif()
   if(SDL_SSE4_1)
+   if(APPLE AND SDL_CPU_X64 AND SDL_CPU_ARM64)
+    set(HAVE_SSE4_1 TRUE)
+    message("SSE4.1 enabled for Apple multi-arch config")
+   else()
     cmake_push_check_state()
     if(USE_GCC OR USE_CLANG OR USE_INTELCC)
       string(APPEND CMAKE_REQUIRED_FLAGS " -msse4.1")
@@ -782,8 +805,13 @@ if(SDL_ASSEMBLY)
     if(COMPILER_SUPPORTS_SSE4_1)
       set(HAVE_SSE4_1 TRUE)
     endif()
+   endif()
   endif()
   if(SDL_SSE4_2)
+   if(APPLE AND SDL_CPU_X64 AND SDL_CPU_ARM64)
+    set(HAVE_SSE4_2 TRUE)
+    message("SSE4.2 enabled for Apple multi-arch config")
+   else()
     cmake_push_check_state()
     if(USE_GCC OR USE_CLANG OR USE_INTELCC)
       string(APPEND CMAKE_REQUIRED_FLAGS " -msse4.2")
@@ -800,8 +828,13 @@ if(SDL_ASSEMBLY)
     if(COMPILER_SUPPORTS_SSE4_2)
       set(HAVE_SSE4_2 TRUE)
     endif()
+   endif()
   endif()
   if(SDL_AVX)
+   if(APPLE AND SDL_CPU_X64 AND SDL_CPU_ARM64)
+    set(HAVE_AVX TRUE)
+    message("AVX enabled for Apple multi-arch config")
+   else()
     cmake_push_check_state()
     if(USE_GCC OR USE_CLANG OR USE_INTELCC)
       string(APPEND CMAKE_REQUIRED_FLAGS " -mavx")
@@ -821,8 +854,13 @@ if(SDL_ASSEMBLY)
     if(COMPILER_SUPPORTS_AVX)
       set(HAVE_AVX TRUE)
     endif()
+   endif()
   endif()
   if(SDL_AVX2)
+   if(APPLE AND SDL_CPU_X64 AND SDL_CPU_ARM64)
+    set(HAVE_AVX2 TRUE)
+    message("AVX2 enabled for Apple multi-arch config")
+   else()
     cmake_push_check_state()
     if(USE_GCC OR USE_CLANG OR USE_INTELCC)
       string(APPEND CMAKE_REQUIRED_FLAGS " -mavx2")
@@ -842,8 +880,13 @@ if(SDL_ASSEMBLY)
     if(COMPILER_SUPPORTS_AVX2)
       set(HAVE_AVX2 TRUE)
     endif()
+   endif()
   endif()
   if(SDL_AVX512F)
+   if(APPLE AND SDL_CPU_X64 AND SDL_CPU_ARM64)
+    set(HAVE_AVX512F TRUE)
+    message("AVX512F enabled for Apple multi-arch config")
+   else()
     cmake_push_check_state()
     if(USE_GCC OR USE_CLANG OR USE_INTELCC)
       string(APPEND CMAKE_REQUIRED_FLAGS " -mavx512f")
@@ -863,9 +906,13 @@ if(SDL_ASSEMBLY)
     if(COMPILER_SUPPORTS_AVX512F)
       set(HAVE_AVX512F TRUE)
     endif()
+   endif()
   endif()
 
   if(SDL_ARMNEON)
+   if(APPLE AND SDL_CPU_X64 AND SDL_CPU_ARM64)
+    set(HAVE_ARMNEON TRUE)
+   else()
     check_c_source_compiles("
         #include <arm_neon.h>
         void floats_add(float *dest, float *a, float *b, unsigned size) {
@@ -881,6 +928,7 @@ if(SDL_ASSEMBLY)
     if(COMPILER_SUPPORTS_ARMNEON)
       set(HAVE_ARMNEON TRUE)
     endif()
+   endif()
   endif()
 
   if(USE_GCC OR USE_CLANG)

sezero · 2025-08-31T17:31:23Z

See #13839 for an alternative to patch/2

Reference issue libsdl-org#12731

sezero

Checks in Apple multi-arch configs are pointless IMO.

Besides the NEON check seems to always fail...

expands to <nothing> on e.g. Windows, which will be interpreted as true by cmake_dependent_option.

madebr · 2025-08-31T19:59:26Z

Checks in Apple multi-arch configs are pointless IMO.

The errors were because of a copy/paste error (using TARGET_CPU_X86 || TARGET_CPU_X86_64 for arm).

Besides the NEON check seems to always fail...

I'd prefer to keep the tests, and let the "fast" things move to cmake/PreseedXXXCache.cmake

sezero · 2025-08-31T20:09:05Z

Checks in Apple multi-arch configs are pointless IMO.

I'd prefer to keep the tests, and let the "fast" things move to cmake/PreseedXXXCache.cmake

OK, we won't agree :)

I'll defer to Sam's judgement.

sezero · 2025-09-02T19:09:43Z

Now that Sam approved this one, I'd like to close #13839.
Is the following good on top of your patch?

diff --git a/CMakeLists.txt b/CMakeLists.txt
index 9591315..f8bb29d 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -80,6 +80,12 @@ include("${SDL3_SOURCE_DIR}/cmake/PreseedNokiaNGageCache.cmake")
 
 SDL_DetectCompiler()
 SDL_DetectTargetCPUArchitectures(SDL_CPUS)
+if(APPLE AND CMAKE_OSX_ARCHITECTURES)
+  list(LENGTH CMAKE_OSX_ARCHITECTURES _num_arches)
+  if(_num_arches GREATER 1)
+    set(APPLE_MULTIARCH TRUE)
+  endif()
+endif()
 
 # Increment this if there is an incompatible change - but if that happens,
 # we should rename the library from SDL3 to SDL4, at which point this would
diff --git a/cmake/sdlcompilers.cmake b/cmake/sdlcompilers.cmake
index f4e43b7..af80a8e 100644
--- a/cmake/sdlcompilers.cmake
+++ b/cmake/sdlcompilers.cmake
@@ -165,20 +165,19 @@ function(check_x86_source_compiles BODY VAR)
   if(ARGN)
     message(FATAL_ERROR "Unknown arguments: ${ARGN}")
   endif()
-  if(APPLE AND DEFINED CMAKE_OSX_ARCHITECTURES)
+  if(APPLE_MULTIARCH AND (SDL_CPU_X86 OR SDL_CPU_X64))
     set(test_conditional 1)
   else()
     set(test_conditional 0)
   endif()
   check_c_source_compiles("
     #if ${test_conditional}
-    # include \"TargetConditionals.h\"
-    # if TARGET_CPU_X86 || TARGET_CPU_X86_64
+    # if defined(__i386__) || defined(__x86_64__)
     #  define test_enabled 1
     # else
-    #  define test_enabled 0
+    #  define test_enabled 0 /* feign success in Apple multi-arch configs */
     # endif
-    #else
+    #else                    /* test normally */
     # define test_enabled 1
     #endif
     #if test_enabled
@@ -196,20 +195,19 @@ function(check_arm_source_compiles BODY VAR)
   if(ARGN)
     message(FATAL_ERROR "Unknown arguments: ${ARGN}")
   endif()
-  if(APPLE AND DEFINED CMAKE_OSX_ARCHITECTURES)
+  if(APPLE_MULTIARCH AND (SDL_CPU_ARM32 OR SDL_CPU_ARM64))
     set(test_conditional 1)
   else()
     set(test_conditional 0)
   endif()
   check_c_source_compiles("
     #if ${test_conditional}
-    # include \"TargetConditionals.h\"
-    # if TARGET_CPU_ARM || TARGET_CPU_ARM64
+    # if defined(__arm__) || defined(__aarch64__)
     #  define test_enabled 1
     # else
-    #  define test_enabled 0
+    #  define test_enabled 0 /* feign success in Apple multi-arch configs */
     # endif
-    #else
+    #else                    /* test normally */
     # define test_enabled 1
     #endif
     #if test_enabled

madebr · 2025-09-02T19:30:21Z

Now that Sam approved this one, I'd like to close #13839. Is the following good on top of your patch?

Makes total sense to me. Feel free to apply (and while you're at it, also cherry-pick this one to the 3.2.x branch).

sezero · 2025-09-02T19:37:10Z

Makes total sense to me. Feel free to apply

Applied as 83bb0f9

(and while you're at it, also cherry-pick this one to the 3.2.x branch).

Done

sezero approved these changes Apr 3, 2025

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sezero requested a review from slouken April 3, 2025 19:43

sezero mentioned this pull request Apr 3, 2025

SDL2_Image: Weird cross compile error on macOS arm64 building for x86_64 libsdl-org/SDL_image#537

Closed

slouken added this to the 3.4.0 milestone Apr 3, 2025

madebr marked this pull request as draft April 3, 2025 19:54

madebr force-pushed the cmake-apple-fat-simd branch from be99236 to 7c9a6c9 Compare April 3, 2025 20:01

madebr marked this pull request as ready for review April 3, 2025 20:15

sezero reviewed Apr 3, 2025

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sezero self-requested a review April 4, 2025 20:45

slouken assigned icculus Aug 26, 2025

sezero mentioned this pull request Aug 31, 2025

cmake: enable x86 and neon simd for Apple multi-arch configurations #13839

Closed

sezero added a commit to sezero/SDL that referenced this pull request Aug 31, 2025

cmake: enable x86 and neon simd for Apple multi-arch configurations

8bb39c6

Reference issue libsdl-org#12731

madebr force-pushed the cmake-apple-fat-simd branch from 7c9a6c9 to f9b8955 Compare August 31, 2025 17:40

sezero added a commit to sezero/SDL that referenced this pull request Aug 31, 2025

cmake: enable x86 and neon simd for Apple multi-arch configurations

e766834

Reference issue libsdl-org#12731

slouken approved these changes Aug 31, 2025

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sezero requested changes Aug 31, 2025

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cmake: use APPLE in dep_option

2cddb69

expands to <nothing> on e.g. Windows, which will be interpreted as true by cmake_dependent_option.

madebr force-pushed the cmake-apple-fat-simd branch from f9b8955 to 731311f Compare August 31, 2025 19:57

madebr added 2 commits August 31, 2025 22:06

cmake: use 'TargetConditionals.h' on Apple for SIMD tests

e8bdbb4

cmake: fix SDL_UNINSTALL post-configuration report

bdf2486

madebr force-pushed the cmake-apple-fat-simd branch from 731311f to bdf2486 Compare August 31, 2025 20:06

slouken approved these changes Aug 31, 2025

View reviewed changes

madebr merged commit c0fb71f into libsdl-org:main Sep 2, 2025
41 of 42 checks passed

madebr deleted the cmake-apple-fat-simd branch September 2, 2025 19:30

cmake: use TargetConditionals.h for SIMD testing on Apple #12731

cmake: use TargetConditionals.h for SIMD testing on Apple #12731

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