http://gcc.gnu.org/bugzilla/show_bug.cgi?id=54272
--- Comment #2 from Kazumoto Kojima <kkojima at gcc dot gnu.org> 2012-08-16 11:23:42 UTC --- (In reply to comment #1) For linux environment, libc's abort function is a rather complex function and trapa handler should do equivalent things to keep complete binary compatibility. I guess that it isn't worth to do so. You can introduce simple trapa sequence as an ABI changing -m option on linux, though trap numbers < 32 are allocated for the syscalls and all other numbers are given for debug purposes and generate SIGTRAP with modified pc which points to trapa instruction itself. If the user program uses its own SIGTRAP handlers, this might be problematic. Perhaps the "sleep" instruction will be a candidate because current libc uses it for ABORT_INSTRUCTION, though it would be bad for bare metal cases. BTW, there is a known SH4 core bug for trapa instruction and we are using 5 or r0,r0 instructions just after trapa. See libitm/ config/sh/futex_bits.h for example.
