https://gcc.gnu.org/bugzilla/show_bug.cgi?id=61586
--- Comment #2 from Uroš Bizjak <ubizjak at gmail dot com> ---
(In reply to Uroš Bizjak from comment #1)
> (In reply to Michael Cree from comment #0)
>
> > I wonder if this ICE is related in any way to bug 56858.
>
> No, this one is different. The function trips on (barrier) that follows
> __builtin_trap. Expand will create:
>
> ;; __builtin_trap ();
>
> (insn 668 667 669 (trap_if (const_int 1 [0x1])
> (const_int 0 [0])) -1
> (nil))
>
> (barrier 669 668 0)
>
>
> (gdb) up
> #2 0x0000000000be59e6 in alpha_handle_trap_shadows () at
> /home/uros/gcc-svn/trunk/gcc/config/alpha/alpha.c:8790
> 8790 gcc_unreachable ();
> (gdb) list
> 8785 case CALL_INSN:
> 8786 case CODE_LABEL:
> 8787 goto close_shadow;
> 8788
> 8789 default:
> 8790 gcc_unreachable ();
> 8791 }
> 8792 }
> 8793 else
> 8794 {
>
> (gdb) p debug_rtx (i)
> (barrier 669 668 1514)
>
> Probably __builtin_trap should close trap shadow here. Let's ask rth.
Something like following (untested) patch:
--cut here--
Index: alpha.c
===================================================================
--- alpha.c (revision 211941)
+++ alpha.c (working copy)
@@ -8685,8 +8749,12 @@
/* Annoyingly, get_attr_trap will die on these. */
if (GET_CODE (PATTERN (i)) == USE
|| GET_CODE (PATTERN (i)) == CLOBBER)
- break;
+ continue;
+ /* This is BUGCHK insn, no need to emit trapb. */
+ if (GET_CODE (PATTERN (i)) == TRAP_IF)
+ goto close_shadow_notrapb;
+
summarize_insn (PATTERN (i), &sum, 0);
if ((sum.defd.i & shadow.defd.i)
@@ -8732,6 +8800,7 @@
n = emit_insn_before (gen_trapb (), i);
PUT_MODE (n, TImode);
PUT_MODE (i, TImode);
+ close_shadow_notrapb:
trap_pending = 0;
shadow.used.i = 0;
shadow.used.fp = 0;
--cut here--
(I also wonder why we have to break the loop for naked USEs and CLOBBERs. We
should just skip the problematic insn and continue - as proposed in the above
patch).
