http://gcc.gnu.org/bugzilla/show_bug.cgi?id=52367
Bug #: 52367
Summary: Many incorrect thumb insn lengths
Classification: Unclassified
Product: gcc
Version: 4.7.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: target
AssignedTo: unassig...@gcc.gnu.org
ReportedBy: ste...@gcc.gnu.org
Many insns in thumb mode have the wrong length attribute.
A trivial test case shows the problem for a few movsi insns:
$ cat t.c
int a, b, c;
void
foo (int x, int *y, int **z)
{
a = x;
b = x + *y;
c = x + *y * **z;
}
$ ./xgcc -B. -c t.c -dp -o t.o -Wa,-a=t.c.list -mcpu=cortex-a9 -mthumb -Os
$ cat t.c.list
ARM GAS /tmp/ccXBH3qs.s page 1
1 .syntax unified
2 .cpu cortex-a9
3 .fpu softvfp
4 .eabi_attribute 20, 1
5 .eabi_attribute 21, 1
6 .eabi_attribute 23, 3
7 .eabi_attribute 24, 1
8 .eabi_attribute 25, 1
9 .eabi_attribute 26, 1
10 .eabi_attribute 30, 4
11 .eabi_attribute 34, 1
12 .eabi_attribute 18, 4
13 .thumb
14 .file "t.c"
15 .text
16 .align 1
17 .global foo
18 .thumb
19 .thumb_func
20 .type foo, %function
21 foo:
22 @ args = 0, pretend = 0, frame = 0
23 @ frame_needed = 0, uses_anonymous_args = 0
24 0000 074B ldr r3, .L2 @ 8 *thumb2_movsi_insn/5
[length = 4]
25 0002 10B5 push {r4, lr} @ 27 *push_multi [length =
2]
26 0004 1268 ldr r2, [r2, #0] @ 15 *thumb2_movsi_insn/5
[length = 4]
27 0006 1860 str r0, [r3, #0] @ 9 *thumb2_movsi_insn/7
[length = 4]
28 0008 0B68 ldr r3, [r1, #0] @ 11 *thumb2_movsi_insn/5
[length = 4]
29 000a 064C ldr r4, .L2+4 @ 24 *thumb2_movsi_insn/5
[length = 4]
30 000c C318 adds r3, r0, r3 @ 12 *thumb2_addsi_short/1
[length = 2]
31 000e 2360 str r3, [r4, #0] @ 13 *thumb2_movsi_insn/7
[length = 4]
32 0010 0B68 ldr r3, [r1, #0] @ 16 *thumb2_movsi_insn/5
[length = 4]
33 0012 1268 ldr r2, [r2, #0] @ 17 *thumb2_movsi_insn/5
[length = 4]
34 0014 02FB0300 mla r0, r2, r3, r0 @ 19 *mulsi3addsi_v6
[length = 4]
35 0018 034B ldr r3, .L2+8 @ 23 *thumb2_movsi_insn/5
[length = 4]
36 001a 1860 str r0, [r3, #0] @ 20 *thumb2_movsi_insn/7
[length = 4]
37 001c 10BD pop {r4, pc} @ 30 *thumb2_return [length
= 12]
38 .L3:
39 001e 00BF .align 2
40 .L2:
41 0020 00000000 .word a
42 0024 00000000 .word b
43 0028 00000000 .word c
44 .size foo, .-foo
45 .comm c,4,4
46 .comm b,4,4
47 .comm a,4,4
48 .ident "GCC: (GNU) 4.7.0 20120218 (experimental)
[trunk revision 184372]"
ARM GAS /tmp/ccXBH3qs.s page 2
DEFINED SYMBOLS
*ABS*:0000000000000000 t.c
/tmp/ccXBH3qs.s:16 .text:0000000000000000 $t
/tmp/ccXBH3qs.s:21 .text:0000000000000000 foo
/tmp/ccXBH3qs.s:41 .text:0000000000000020 $d
*COM*:0000000000000004 a
*COM*:0000000000000004 b
*COM*:0000000000000004 c
NO UNDEFINED SYMBOLS
$
The same can happen for at least the following insns:
611 048c 1A88 ldrh r2, [r3, #0] @ 504
*thumb2_zero_extendhisi2_v6/2 [length = 4]
293 0202 0130 adds r0, r0, #1 @ 171 *cmpsi2_addneg/1
[length = 4]
3459 190a 61D1 bne .L921 @ 84 *arm_cond_branch [length
= 4]
4220 1eae 79D8 bhi .L1131 @ 236 *arm_cond_branch
[length = 4]
4235 1ecc 6AD1 bne .L1131 @ 254 *arm_cond_branch
[length = 4]
4238 1ed2 67D9 bls .L1131 @ 258 *arm_cond_branch
[length = 4]
4271 1f28 CD1E subs r5, r1, #3 @ 718 *subsi3_compare/1
[length = 4]
4272 1f2a 6942 rsbs r1, r5, #0 @ 719 *subsi3_compare/2
[length = 4]
4273 1f2c 6941 adcs r1, r1, r5 @ 720
*addsi3_carryin_clobercc_geu [length = 4]
1374 0972 9847 blx r3 @ 47 *call_value_reg_thumb2
[length = 4]
396 02b8 9847 blx r3 @ 236 *call_reg_thumb2 [length =
4]
135 009e 002A cmp r2, #0 @ 40 *thumb2_cbnz/1 [length
= 8]
136 00a0 33D1 bne .L11
319 0210 0028 cmp r0, #0 @ 466 *thumb2_movcond/2
[length = 10]
320 0212 18BF it ne
321 0214 0546 movne r5, r0
It can also happen with conditional execution:
614 0494 0CBF ite eq
615 0496 DB6B ldreq r3, [r3, #60] @ 509 *p
*thumb2_movsi_insn/5 [length = 6]
616 0498 9B69 ldrne r3, [r3, #24] @ 514 *p
*thumb2_movsi_insn/5 [length = 6]
85 005e 38BF it cc
86 0060 0020 movcc r0, #0 @ 44 *p *thumb2_movsi_insn/2
[length = 6]
