------- Additional Comments From danglin at gcc dot gnu dot org 2004-04-04
20:54 -------
The ICE is generated by a call to insn_default_length in
pa_output_function_epilogue. It does a call to get_last_nonnote_insn
to get the last nonnote insn. However, in this case, get_last_nonnote_insn
doesn't actually return the last nonnote insn. It returns the next to
last nonnote insn which is the `use' insn which insn_default_length
doesn't like.
The code in get_last_nonnote_insn assumes that the last insn in the
current sequence or current function is a note. However, when
get_last_nonnote_insn is called, the last insn is
(jump_insn 55 31 0 (parallel [
(return)
(use (reg:SI 2 %r2))
(const_int 0 [0x0])
]) 184 {return} (insn_list:REG_DEP_ANTI 31 (insn_list 41 (nil)))
(expr_list:REG_BR_PRED (const_int 12 [0xc])
(expr_list:REG_DEAD (reg:SI 2 %r2)
(nil))))
We did have the following note:
(note 71 55 0 NOTE_INSN_DELETED)
However, it is removed by a call to remove_insn:
Breakpoint 13, remove_insn (insn=0x40196580) at ../../gcc/gcc/emit-rtl.c:3578
3578 rtx next = NEXT_INSN (insn);
(gdb) bt
#0 remove_insn (insn=0x40196580) at ../../gcc/gcc/emit-rtl.c:3578
#1 0x0011bb8c in delete_insn (insn=0x40196580) at ../../gcc/gcc/cfgrtl.c:149
#2 0x00113f5c in reemit_insn_block_notes () at ../../gcc/gcc/cfglayout.c:559
#3 0x001ebef0 in final_start_function (first=0x401961a0, file=0x66ddd0,
optimize=2) at ../../gcc/gcc/final.c:1374
#4 0x00470108 in rest_of_handle_final (decl=0x4021af50, insns=0x401961a0)
at ../../gcc/gcc/passes.c:447
The comment for NOTE_INSN_DELETED says
/* This note is used to get rid of an insn
when it isn't safe to patch the insn out of the chain. */
So, I don't think delete_insn should be trying to remove this note. If
the note isn't removed, then get_last_nonnote_insn will work correctly
and we shouldn't get the ICE.
--
What |Removed |Added
----------------------------------------------------------------------------
CC| |hubicka at gcc dot gnu dot
| |org
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=14838
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