Fix CPU detection and SIMD on modern Mac/cmake combos

With recent versions of cmake on Mac, the CPU detection
program failed to compile since it was very fragile (buggy)
with respect to how compiler flags were defined - and that
in turn will mean losing all SIMD support.
This will fix the build, and it also adds a more vocal warning
if the CPU detection code cannot be compiled at all.

Change-Id: Idcdc8b59a4252b3faf8572311d2ca63a4d2a1bc0

diff --git a/cmake/gmxDetectCpu.cmake b/cmake/gmxDetectCpu.cmake
index d5a8f12a2c3fffce16a1425198e98070521d752d..ed5fc17c39d61d3ecfc438d5deae26156ae866a9 100644 (file)
--- a/cmake/gmxDetectCpu.cmake
+++ b/cmake/gmxDetectCpu.cmake
@@ -1,7 +1,7 @@
 #
 # This file is part of the GROMACS molecular simulation package.
 #
-# Copyright (c) 2012,2013,2014,2015,2016,2017, by the GROMACS development team, led by
+# Copyright (c) 2012,2013,2014,2015,2016,2017,2019, by the GROMACS development team, led by
 # Mark Abraham, David van der Spoel, Berk Hess, and Erik Lindahl,
 # and including many others, as listed in the AUTHORS file in the
 # top-level source directory and at http://www.gromacs.org.
@@ -78,13 +78,13 @@ function(gmx_run_cpu_detection TYPE)
             # for x86 we need inline assembly to use cpuid
             gmx_test_inline_asm_gcc_x86(GMX_X86_GCC_INLINE_ASM)
             if(GMX_X86_GCC_INLINE_ASM)
-                set(GCC_INLINE_ASM_DEFINE "-DGMX_X86_GCC_INLINE_ASM=1")
+                set(GCC_INLINE_ASM_DEFINE -DGMX_X86_GCC_INLINE_ASM=1)
             else()
-                set(GCC_INLINE_ASM_DEFINE "-DGMX_X86_GCC_INLINE_ASM=0")
+                set(GCC_INLINE_ASM_DEFINE -DGMX_X86_GCC_INLINE_ASM=0)
             endif()
 
-            set(_compile_definitions "${GCC_INLINE_ASM_DEFINE} -I${PROJECT_SOURCE_DIR}/src -DGMX_CPUINFO_STANDALONE ${GMX_STDLIB_CXX_FLAGS} -DGMX_TARGET_X86=${GMX_TARGET_X86_VALUE}")
-            set(LINK_LIBRARIES "${GMX_STDLIB_LIBRARIES}")
+            set(_compile_definitions ${GCC_INLINE_ASM_DEFINE};-I${PROJECT_SOURCE_DIR}/src;-DGMX_CPUINFO_STANDALONE=1;-DGMX_TARGET_X86=${GMX_TARGET_X86_VALUE})
+            set(LINK_LIBRARIES ${GMX_STDLIB_LIBRARIES})
             try_compile(CPU_DETECTION_COMPILED
                 "${PROJECT_BINARY_DIR}"
                 "${PROJECT_SOURCE_DIR}/src/gromacs/hardware/cpuinfo.cpp"
@@ -93,7 +93,11 @@ function(gmx_run_cpu_detection TYPE)
                 OUTPUT_VARIABLE CPU_DETECTION_COMPILED_OUTPUT
                 COPY_FILE ${CPU_DETECTION_BINARY})
             if(NOT CPU_DETECTION_COMPILED AND NOT RUN_CPU_DETECTION_COMPILATION_QUIETLY)
-                message(STATUS "Did not detect build CPU ${LOWERTYPE} - detection program did not compile")
+                if(GMX_TARGET_X86)
+                    message(WARNING "CPU detection program did not compile on x86 host - this should never happen. It is VERY bad for performance, since you will lose all SIMD support. Please file a bug report.")
+                else()
+                    message(WARNING "Did not detect build CPU ${LOWERTYPE} - detection program did not compile. Please file a bug report if this is a common platform.")
+                endif()
             endif()
             set(RUN_CPU_DETECTION_COMPILATION_QUIETLY TRUE CACHE INTERNAL "Keep quiet on any future compilation attempts")
         endif()