[Bug middle-end/23954] [4.1/4.2 regression] FAIL: gcc.c-torture/execute/20040709-1.c execution, -Os

["danglin at gcc dot gnu dot org" <gcc-bugzilla at gcc dot gnu dot org>]

------- Comment #14 from danglin at gcc dot gnu dot org  2005-12-19 04:45 -------
I did a checkout as of Sep 12, 2005 00:00:00 UTC and get the same assembly
code as in the initial report using the following compilation options:
"-Os -w -S -mschedule=7100LC".  The build was done on hppa2.0w-hp-hpux11.11.

Here's some rtl from 54.barriers and 55.dbr showing the end of the initial
loop in the function testB:

(jump_insn:TI 18 15 186 (set (pc)
        (if_then_else (ne (reg/v/f:SI 6 %r6 [orig:98 p___4463 ] [98])
                (reg/f:SI 19 %r19 [111]))
            (label_ref:SI 11)
            (pc))) 25 {*pa.md:1700} (insn_list:REG_DEP_TRUE 17
(insn_list:REG_DE
P_ANTI 13 (insn_list:REG_DEP_TRUE 15 (nil))))
    (expr_list:REG_DEAD (reg/f:SI 19 %r19 [111])
        (expr_list:REG_BR_PROB (const_int 8750 [0x222e])
            (nil))))

(note 186 18 20 NOTE_INSN_LOOP_END)

(note 20 186 45 [bb 2] NOTE_INSN_BASIC_BLOCK)

(note 45 20 23 NOTE_INSN_DELETED)

(insn:TI 23 45 21 (set (reg:SI 28 %r28 [114])
        (mem/s/j/c:SI (plus:SI (reg/v/f:SI 6 %r6 [orig:98 p___4463 ] [98])
                (const_int -8 [0xfffffff8])) [0+0 S4 A32])) 37 {*pa.md:2291}
(ni
l)
    (expr_list:REG_EQUAL (mem/s/j/c:SI (plus:SI (reg/v/f:SI 6 %r6 [orig:98
p___4
463 ] [98])
                (const_int -8 [0xfffffff8])) [0+0 S4 A32])
        (nil)))

(insn 21 23 196 (set (reg:SI 1 %r1)
        (high:SI (symbol_ref:SI ("sB") [flags 0x80] <var_decl 7afc1bb0 sB>)))
48
 {*pa.md:2737} (nil)
    (expr_list:REG_EQUIV (high:SI (symbol_ref:SI ("sB") [flags 0x80] <var_decl
7
afc1bb0 sB>))
        (nil)))

----

(insn 253 15 186 (sequence [
            (jump_insn:TI 18 15 23 (set (pc)
                    (if_then_else (ne (reg/v/f:SI 6 %r6 [orig:98 p___4463 ]
[98]
)
                            (reg/f:SI 19 %r19 [111]))
                        (label_ref:SI 11)
                        (pc))) 25 {*pa.md:1700} (insn_list:REG_DEP_TRUE 17
(insn
_list:REG_DEP_ANTI 13 (insn_list:REG_DEP_TRUE 15 (nil))))
                (expr_list:REG_BR_PRED (const_int 6 [0x6])
                    (expr_list:REG_DEAD (reg/f:SI 19 %r19 [111])
                        (expr_list:REG_BR_PROB (const_int 8750 [0x222e])
                            (nil)))))
            (insn:TI 23 18 186 (set (reg:SI 28 %r28 [114])
                    (mem/s/j/c:SI (plus:SI (reg/v/f:SI 6 %r6 [orig:98 p___4463
]
 [98])
                            (const_int -8 [0xfffffff8])) [0+0 S4 A32])) 37
{*pa.
md:2291} (nil)
                (expr_list:REG_EQUAL (mem/s/j/c:SI (plus:SI (reg/v/f:SI 6 %r6
[o
rig:98 p___4463 ] [98])
                            (const_int -8 [0xfffffff8])) [0+0 S4 A32])
                    (nil)))
        ]) -1 (nil)
    (nil))

(note 186 253 20 NOTE_INSN_LOOP_END)

(note 20 186 45 [bb 2] NOTE_INSN_BASIC_BLOCK)

(note 45 20 21 NOTE_INSN_DELETED)

(insn 21 45 196 (set (reg:SI 1 %r1)
        (high:SI (symbol_ref:SI ("sB") [flags 0x80] <var_decl 7afc1bb0 sB>)))
48
 {*pa.md:2737} (nil)
    (expr_list:REG_EQUIV (high:SI (symbol_ref:SI ("sB") [flags 0x80] <var_decl
7
afc1bb0 sB>))
        (nil)))

As can be seen, the memory load that causes the segmentation fault was outside
the loop in the 54.barriers pass.

>From an optimisation standpoint, I'm a bit surprised that the memory load
was selected for placement into the delay slot rather than the following set.


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=23954