https://gcc.gnu.org/bugzilla/show_bug.cgi?id=91970
--- Comment #12 from Rich Felker <bugdal at aerifal dot cx> --- There's some awful hand-written asm in libgcc/config/arm/ieee754-df.S replacing the standard libgcc2.c versions; that's the problem. But in order to use the latter it would need to be compiled with -mfloat-abi=softfp since the __aeabi_l2d function (and all the __aeabi_* apparently) use the standard soft-float EABI even on EABIHF targets. I'm not sure why you want a library function to be called for this on hardfloat targets anyway. Inlining the hi*0x1p32+lo is almost surely smaller than the function call, counting spills and conversion of the result back from GP registers to an FP register. It seems like GCC should be able to inline this idiom at a high level for *all* targets that lack a floatdidf operation but have floatsidf. Of course a high level fix is going to be hell to backport, and this really needs a backportable fix or workaround (maintained in mcm not upstream gcc) from musl perspective. Maybe the easiest way to do that is just to hack the right preprocessor conditions for a hardfloat implementation into ieee754-df.S...
