http://gcc.gnu.org/bugzilla/show_bug.cgi?id=45792
Summary: [4.6 Regression]: cris-elf build failure (hangs) due to fix for PR44374 Product: gcc Version: 4.6.0 Status: UNCONFIRMED Keywords: build Severity: normal Priority: P3 Component: rtl-optimization AssignedTo: unassig...@gcc.gnu.org ReportedBy: h...@gcc.gnu.org CC: ber...@gcc.gnu.org Host: x86_64-unknown-linux-gnu Target: cris-*-* Created attachment 21882 --> http://gcc.gnu.org/bugzilla/attachment.cgi?id=21882 Preprocessed dtoa.c At r164551 the tree built with few regressions. At r164560 building newlib/libc/stdlib/dtoa.c hangs (cpu-time > 38 hours) and at r164619 the build is at a similar state (didn't wait 38 hours, but see below). Attaching a gdb-session to the running cc1 at r164619 shows an infinite loop in gcc/emit-rtl.c:reorder_insns: 4027 for (x = from; x != NEXT_INSN (to); x = NEXT_INSN (x)) 4028 if (!BARRIER_P (x)) 4029 df_insn_change_bb (x, bb); But "x" is bogus; it seems to have been deleted or at least removed from the insn stream: (insn 2210 2210 2210 239 (set (cc0) (compare (reg/v/f:SI 3 r3 [orig:95 mlo ] [95]) (reg/v/f:SI 4 r4 [orig:97 mhi ] [97]))) /tmp/hpautotest-gcc1/gcc/newlib/libc/stdlib/dtoa.c:808 11 {*cmpsi} (nil)) The call to df_insn_change_bb takes the (old_bb == new_bb) early return. Author of suspect patch in revision range CC:ed. Preprocessed dtoa.c attached. Compile with -O2.