Hi : In regmove.c there is function "replace_in_call_usage" called in fixup_match_1, It replaces dst register by src in call_insn, I suspect whether it is necessary Since comment of CALL_INSN_FUNCTION_USAGE says that no pseudo register can appear in it and seems src is pseudo register.
further more, no replace(dst->src) is done when building bootstrap gcc-4.2.4, which confirmed my understanding. Is it right or I've missed something important? Please help. Thanks in advance. -- Best Regards.
