> Peter Leist <peterle...@googlemail.com> writes: > > > can I use emit_cmp_and_jump_insns while creating the function > > prologue/epilogue? > > If I try, I always get an error at runtime > > > > func.c:33: internal compiler error: in make_edges, at cfgbuild.c:354 > > > > I think this is because the jump doesn't get an JUMP_LABEL associated to it. > > Is there an other way at this pass to add loops to the code? > > Using a general function like emit_cmp_and_jump_insns when generating > the prologue is somewhat risky, because emit_cmp_and_jump_insns expects > to be run before reload. It freely calls functions like force_reg and > gen_reg_rtx which may not be used before reload. > > In the function prologue you should know precisely which insns you want > to emit. It will be safer in general to use emit_insn (gen_XXX ()) > rather than to call a general routine. > > I don't know of any existing cases where the prologue needs a jump, but > it should be easy enough to emit a jump insn and set JUMP_LABEL > yourself.
x86_64 has jump around saving SSE regs for variadic function prologue. Honza > > Ian
