Hi! On Wed, Mar 06, 2019 at 07:15:54PM +0100, Sébastien Michelland wrote: > I'm having trouble building programs for a SuperH-4 target without FPU. > > My current setup uses an sh4eb-nofpu-elf target which usually behaves > very well (much better than sh4eb-elf that uses a lot of fmov for > optimization), but I discovered that using a va_list causes the dreaded, > illegal fmov instruction to be generated. > > I've looked up available options and expected -m4-nofpu to be of help, > however GCC does not agree with this estimation: > > sh4eb-nofpu-elf-gcc: error: command line option '-m4-nofpu' is not > supported by this configuration > > When building I expected this target to support the option "by default". > I've tried building again and I found no relevant flag, even in the > recursive configure help. > > Here is what the compiler looks like in more detail: > > Using built-in specs. > COLLECT_GCC=sh4eb-nofpu-elf-gcc > > COLLECT_LTO_WRAPPER=/home/el/opt/sh4eb-nofpu-elf-2.32-8.3.0/libexec/gcc/sh4eb-nofpu-elf/8.3.0/lto-wrapper > Target: sh4eb-nofpu-elf > Configured with: ../gcc-8.3.0/configure > --prefix=/home/el/opt/sh4eb-nofpu-elf-2.32-8.3.0 > --target=sh4eb-nofpu-elf --enable-languages=c,c++ --without-headers > --with-newlib --disable-nls --disable-werror --enable-libssp --enable-lto > Thread model: single > gcc version 8.3.0 (GCC) > > How can I fix this setup to generate entirely FPU-free programs? There is https://gcc.gnu.org/PR64008 which probably is relevant. Configuring with --enable-targets=all will help. I use this patch for sh, that may help too: diff --git a/gcc/config/sh/sh.h b/gcc/config/sh/sh.h index 0204872..7f126ce 100644 --- a/gcc/config/sh/sh.h +++ b/gcc/config/sh/sh.h @@ -124,6 +124,9 @@ extern int code_for_indirect_jump_scratch; #define SUPPORT_SH2A_NOFPU 1 #endif #if SUPPORT_SH3 +#define SUPPORT_SH4 1 +#endif +#if SUPPORT_SH4 #define SUPPORT_SH4_NOFPU 1 #endif #if SUPPORT_SH4_NOFPU Segher
