The simplest way is going to be something like fprintf (asm_out_file, "\tnop\n");
I added fprintf (asm_out_file, "\tnop\n"); to the end of case CODE_LABEL. Then I recompile the gcc. Unfortunately, it doesn't seem that a NOP was inserted. Any ideaes? case CODE_LABEL: /* The target port might emit labels in the output function for some insn, e.g. sh.c output_branchy_insn. */ if (CODE_LABEL_NUMBER (insn) <= max_labelno) { int align = LABEL_TO_ALIGNMENT (insn); #ifdef ASM_OUTPUT_MAX_SKIP_ALIGN int max_skip = LABEL_TO_MAX_SKIP (insn); #endif if (align && NEXT_INSN (insn)) { #ifdef ASM_OUTPUT_MAX_SKIP_ALIGN ASM_OUTPUT_MAX_SKIP_ALIGN (file, align, max_skip); #else #ifdef ASM_OUTPUT_ALIGN_WITH_NOP ASM_OUTPUT_ALIGN_WITH_NOP (file, align); #else ASM_OUTPUT_ALIGN (file, align); #endif #endif } } fprintf (asm_out_file, "\tnop\n");