Auto-detect __builtin_complex

This is needed to implement the CMPLX* macros correctly.

Signed-off-by: Keith Packard <[email protected]>

Author: keith-packard

CMakeLists.txt

@@ -194,6 +194,9 @@ picolibc_flag(_HAVE_CC_INHIBIT_LOOP_TO_LIBCALL)
 # Compiler supports _Complex
 picolibc_flag(_HAVE_COMPLEX)
 
+# Compiler supports __builtin_complex
+picolibc_flag(_HAVE_BUILTIN_COMPLEX)
+
 # Compiler supports format function attribute
 picolibc_flag(_HAVE_FORMAT_ATTRIBUTE 1)
 

cmake/have-builtin-complex.c

@@ -0,0 +1,2 @@
+static double _Complex test(double r, double i) { return __builtin_complex(r, i); }
+int main(void) { test(1.0, 2.0); return 0; }

meson.build

@@ -811,6 +811,13 @@ float _Complex test(float _Complex z) { return z; }
 '''
 have_complex = cc.compiles(complex_code, name : 'supports _Complex', args: core_c_args)
 
+builtin_complex_code = '''
+#include <stddef.h>
+double _Complex test(double r, double i) { return __builtin_complex(r, i); }
+'''
+
+have_builtin_complex = have_complex and cc.compiles(builtin_complex_code, name : 'supports __builtin_complex', args: core_c_args)
+
 # CompCert does not have __builtin_expect
 builtin_expect_code = '''
 volatile int a = 42;
@@ -1050,6 +1057,7 @@ conf_data.set('_HAVE_BITFIELDS_IN_PACKED_STRUCTS', have_bitfields_in_packed_stru
 conf_data.set('_HAVE_BUILTIN_MUL_OVERFLOW', have_builtin_mul_overflow, description: 'Compiler has __builtin_mul_overflow')
 conf_data.set('_HAVE_BUILTIN_ADD_OVERFLOW', have_builtin_add_overflow, description: 'Compiler has __builtin_add_overflow')
 conf_data.set('_HAVE_COMPLEX', have_complex, description: 'Compiler supports _Complex')
+conf_data.set('_HAVE_BUILTIN_COMPLEX', have_builtin_complex, description: 'Compiler has __builtin_complex')
 conf_data.set('_HAVE_BUILTIN_EXPECT', have_builtin_expect, description: 'Compiler has __builtin_expect')
 conf_data.set('_HAVE_ALLOC_SIZE', have_alloc_size, description: 'The compiler REALLY has the attribute __alloc_size__')
 conf_data.set('_HAVE_ATTRIBUTE_ALWAYS_INLINE',

picolibc.h.in

@@ -121,6 +121,9 @@
 /* Compiler supports _Complex */
 #cmakedefine _HAVE_COMPLEX
 
+/* Compiler supports __builtin_complex */
+#cmakedefine _HAVE_BUILTIN_COMPLEX
+
 #cmakedefine _HAVE_FCNTL
 
 #cmakedefine _HAVE_FORMAT_ATTRIBUTE