Suggest `-microarch:native` if `popcnt` instruction is missing.

Fixes #4453.

1 files changed, 35 insertions, 0 deletions

diff --git a/src/build_cpuid.cpp b/src/build_cpuid.cpp
new file mode 100644
index 000000000..a4e44e7f1
--- /dev/null
+++ b/src/build_cpuid.cpp
@@ -0,0 +1,35 @@
+#if !defined(GB_COMPILER_MSVC)
+	#if defined(GB_CPU_X86)
+		#include <cpuid.h>
+	#endif
+#endif
+
+gb_internal void odin_cpuid(int leaf, int result[]) {
+	#if defined(GB_CPU_ARM) || defined(GB_CPU_RISCV)
+		return;
+
+	#elif defined(GB_CPU_X86)
+	
+		#if defined(GB_COMPILER_MSVC)
+			__cpuid(result, leaf);
+		#else
+			__get_cpuid(leaf, (unsigned int*)&result[0], (unsigned int*)&result[1], (unsigned int*)&result[2], (unsigned int*)&result[3]);
+		#endif
+
+	#endif
+}
+
+gb_internal bool should_use_march_native() {
+	#if !defined(GB_CPU_X86)
+		return false;
+
+	#else
+
+		int cpu[4];
+		odin_cpuid(0x1, &cpu[0]); // Get feature information in ECX + EDX
+
+		bool have_popcnt = cpu[2] && (1 << 23); // bit 23 in ECX = popcnt
+		return !have_popcnt;
+
+	#endif
+}
\ No newline at end of file