On 05/10/2012 09:10 AM, Tristan Gingold wrote:
Hi,
I am getting a segfault in ira-color.c:2945 on the trunk:
Program received signal SIGSEGV, Segmentation fault.
0x0000000000a79f37 in move_spill_restore () at ../../src/gcc/ira-color.c:2945
2945 || ira_reg_equiv_const[regno] != NULL_RTX
(gdb) l
2940 /* don't do the optimization because it can create
2941 copies and the reload pass can spill the allocno set
2942 by copy although the allocno will not get memory
2943 slot. */
2944 || ira_reg_equiv_invariant_p[regno]
2945 || ira_reg_equiv_const[regno] != NULL_RTX
2946 || !bitmap_bit_p (loop_node->border_allocnos, ALLOCNO_NUM
(a)))
2947 continue;
2948 mode = ALLOCNO_MODE (a);
2949 rclass = ALLOCNO_CLASS (a);
while building gcc (gnatcmd.adb file) for ia64-vms using a cross compiler
(target=ia64-vms, host=x86_64-linux).
The reason looks to be an out of bounds access:
(gdb) print regno
$10 = 18476
(gdb) print ira_reg_equiv_len
$11 = 17984
(I suppose this setup is not easy at all to reproduce, but I can provide any
files, if necessary).
Tristan, thanks for reporting this.
Wild guess, as I don't know IRA at all: looks like in this file most accesses
to ira_reg_equiv_* are guarded. Is it expected that they aren't at this point ?
Yes, I guess. It is possible to have the pseudos which are out of range
ira_reg_equiv_const. It should be hard to reproduce such error because
they are generated when we need to break circular dependence (e.g. when
hard register 1 should be moved to hard register 2 and hard register 2
to hard register 1).
Your solution is perfectly fine. So you can commit the patch into the
trunk as pre-approved.
Thanks again.
[I am currently trying with the following chunk:
--- a/gcc/ira-color.c
+++ b/gcc/ira-color.c
@@ -2941,8 +2941,9 @@ move_spill_restore (void)
copies and the reload pass can spill the allocno set
by copy although the allocno will not get memory
slot. */
- || ira_reg_equiv_invariant_p[regno]
- || ira_reg_equiv_const[regno] != NULL_RTX
+ || (regno< ira_reg_equiv_len
+&& (ira_reg_equiv_invariant_p[regno]
+ || ira_reg_equiv_const[regno] != NULL_RTX))
|| !bitmap_bit_p (loop_node->border_allocnos, ALLOCNO_NUM (a)))
continue;
mode = ALLOCNO_MODE (a);
]
