https://gcc.gnu.org/bugzilla/show_bug.cgi?id=49611
--- Comment #9 from Ryan Johnson <scovich at gmail dot com> --- (In reply to Andi Kleen from comment #7) > You can do many of these things these days with asm goto, however it > typically requires non-structured control flow (goto labels). I filed this bug after determining that asm goto was unsuitable for this purpose. Goto labels are not a problem per se (actually kind of slick), but asm goto requires all outputs to pass through memory and so is only good for control flow (not computation plus exceptional case). It also requires the actual branching and all attendant glue to happen in assembly. Both limitations increase bulk and hamper the optimizer, and go against (what I thought was) the intention that inline asm normally be used for very small snippets of code the compiler can't handle. At some point you may as well just setcc and do a new comparison/branch outside the asm block; less bug-prone and would probably yield faster and cleaner code, too.
