[Bug middle-end/28749] Miscompilation of glibc/stdio-common/vfprintf.c, invalid delay slot fill.

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

------- Comment #3 from carlos at systemhalted dot org  2006-08-16 06:48 -------
Dumping vfprintf.c compile with -S and -da

        ; basic block 131
.LBE379:
.LBB380:
.LBB380:
        ; vfprintf.c:1448
        .loc 2 1448 0
        ldw 8(%r3),%r28
        ldil L'16384,%r22
        ldb 0(%r28),%r21
.LVL339:
        ldo -6804(%r22),%r22
        extrs %r21,31,8,%r28
        addl %r22,%r3,%r22
        stw %r28,0(%r22)
        ldo -32(%r21),%r20
        ldi 90,%r28 
        extru %r20,31,8,%r20
        ; vfprintf.c:1562
        .loc 2 1562 0
        ; vfprintf.c:1448
        .loc 2 1448 0
        comb,<< %r28,%r20,.L1104
        ldil L'16384,%r21
        ^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Incorrect delay slot fill.

        ; basic block 313
.LVL557:
.L1104:
.LBE425:
.LBE418:
.LBE417:
.LBB426:
        ; vfprintf.c:1562
        .loc 2 1562 0
        ldo -6804(%r21),%r21
        addl %r21,%r3,%r21
        ldw 0(%r21),%r21

bb 313 is missing the first insn.

The output of vfprintf.c.157r.dbr shows:

(barrier 18544 18543 2803)

(note 2803 18544 14801 ("vfprintf.c") 1561)

(note 14801 2803 14802 ( size (expr_list:REG_DEP_TRUE (reg/v:SI 5 %r5 [orig:281
size ] [281])
    (const_int 0 [0x0]))) NOTE_INSN_VAR_LOCATION)

(note 14802 14801 14803 ( function_done (nil)) NOTE_INSN_VAR_LOCATION)

(note 14803 14802 14804 ( size (expr_list:REG_DEP_TRUE (reg/v:SI 5 %r5
[orig:280 size ] [280])
    (const_int 0 [0x0]))) NOTE_INSN_VAR_LOCATION)

(note 14804 14803 14805 ( __self (expr_list:REG_DEP_TRUE (reg/v/f:SI 5 %r5
[orig:364 __self ] [364])
    (const_int 0 [0x0]))) NOTE_INSN_VAR_LOCATION)

(note 14805 14804 14806 ( ptr (expr_list:REG_DEP_TRUE (reg/v/f:SI 21 %r21
[orig:346 ptr ] [346])
    (const_int 0 [0x0]))) NOTE_INSN_VAR_LOCATION)

(note 14806 14805 2804 ( size (expr_list:REG_DEP_TRUE (reg/v:SI 5 %r5 [orig:282
size ] [282])
    (const_int 0 [0x0]))) NOTE_INSN_VAR_LOCATION)

(code_label/s 2804 14806 2805 242 ("do_form_unknown") [1 uses])

(note 2805 2804 2806 [bb 313] NOTE_INSN_BASIC_BLOCK)

(note 2806 2805 14807 ("vfprintf.c") 1562)

(note 14807 2806 19223 ( ptr (nil)) NOTE_INSN_VAR_LOCATION)

(code_label 19223 14807 8862 1104 "" [2 uses])

(insn 8862 19223 8863 vfprintf.c:1562 (set (reg/f:SI 21 %r21)
        (plus:SI (reg/f:SI 21 %r21)
            (const_int -6804 [0xffffe56c]))) 114 {addsi3} (nil)
    (expr_list:REG_EQUAL (const_int 9580 [0x256c])
        (nil))) 

And the set has been moved into bb 131

(insn 19224 831 14145 vfprintf.c:1562 (sequence [
            (jump_insn:TI 833 831 8861 vfprintf.c:1448 (set (pc)
                    (if_then_else (gtu (reg:SI 20 %r20 [782])
                            (reg:SI 28 %r28 [783]))
                        (label_ref:SI 19223)
                        (pc))) -1 (nil)
                (expr_list:REG_BR_PRED (const_int 4 [0x4])
                    (expr_list:REG_DEAD (reg:SI 20 %r20 [782])
                        (expr_list:REG_DEAD (reg:SI 28 %r28 [783])
                            (expr_list:REG_EQUAL (if_then_else (gtu (reg:SI 20
%r20 [782])
                                        (const_int 90 [0x5a]))
                                    (label_ref:SI 19223)
                                    (pc))
                                (expr_list:REG_BR_PROB (const_int 5000
[0x1388])
                                    (nil)))))))
            (insn/s:TI 8861 833 14145 (set (reg/f:SI 21 %r21)
                    (const_int 16384 [0x4000])) 37 {*pa.md:2482} (nil)
                (nil))
        ]) -1 (nil)
    (nil)) 

While vfprintf.c.156r.barriers shows:

(barrier 12266 12265 2803)
(note 2803 12266 14801 ("vfprintf.c") 1561)
(note 14801 2803 14802 ( size (expr_list:REG_DEP_TRUE (reg/v:SI 5 %r5 [orig:281
size ] [281])
    (const_int 0 [0x0]))) NOTE_INSN_VAR_LOCATION)
(note 14802 14801 14803 ( function_done (nil)) NOTE_INSN_VAR_LOCATION)
(note 14803 14802 14804 ( size (expr_list:REG_DEP_TRUE (reg/v:SI 5 %r5
[orig:280 size ] [280])
    (const_int 0 [0x0]))) NOTE_INSN_VAR_LOCATION)
(note 14804 14803 14805 ( __self (expr_list:REG_DEP_TRUE (reg/v/f:SI 5 %r5
[orig:364 __self ] [364])
    (const_int 0 [0x0]))) NOTE_INSN_VAR_LOCATION)
(note 14805 14804 14806 ( ptr (expr_list:REG_DEP_TRUE (reg/v/f:SI 21 %r21
[orig:346 ptr ] [346])
    (const_int 0 [0x0]))) NOTE_INSN_VAR_LOCATION)
(note 14806 14805 2804 ( size (expr_list:REG_DEP_TRUE (reg/v:SI 5 %r5 [orig:282
size ] [282])
    (const_int 0 [0x0]))) NOTE_INSN_VAR_LOCATION)
(code_label/s 2804 14806 2805 242 ("do_form_unknown") [5 uses])
(note 2805 2804 2806 [bb 313] NOTE_INSN_BASIC_BLOCK)
(note 2806 2805 8861 ("vfprintf.c") 1562)
(insn:TI 8861 2806 14807 vfprintf.c:1562 (set (reg/f:SI 21 %r21)
        (const_int 16384 [0x4000])) 37 {*pa.md:2482} (nil)
    (nil))  

That is is still present in the correct basic block before dbr, and the label
and barriers are present.


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=28749