[Bug tree-optimization/49452] [4.7 regression] comp-goto-2.c regresses in testing

[ebotcazou at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=49452

--- Comment #15 from Eric Botcazou <ebotcazou at gcc dot gnu.org> 2011-07-16 
21:18:39 UTC ---
The machine-dependent reorg pass does something unexpected:

(insn 30 18 14 3 (set (reg/f:SI 11 fp)
        (plus:SI (reg/f:SI 11 fp)
            (const_int 36 [0x24]))) 4 {*arm_addsi3}
     (nil))

(insn 14 30 16 3 (use (reg/f:SI 11 fp)) -1
     (nil))

(insn 16 14 24 3 (unspec_volatile [
            (const_int 0 [0])
        ] VUNSPEC_BLOCKAGE) 252 {blockage}
     (nil))

(insn 24 16 27 3 (set (reg/i:SI 0 r0)
        (mem/c:SI (plus:SI (reg/f:SI 11 fp)
                (const_int -56 [0xffffffffffffffc8])) [6 %sfp+-20 S4 A32]))
comp-goto-2.c:26 176 {*arm_movsi_insn}
     (nil))

is reordered into:

(insn 14 18 16 (use (reg/f:SI 11 fp)) -1
     (nil))

(insn 16 14 24 (unspec_volatile [
            (const_int 0 [0])
        ] VUNSPEC_BLOCKAGE) 252 {blockage}
     (nil))

(insn 24 16 30 (set (reg/i:SI 0 r0)
        (mem/c:SI (plus:SI (reg/f:SI 11 fp)
                (const_int -20 [0xffffffffffffffec])) [6 %sfp+-20 S4 A32]))
comp-goto-2.c:26 176 {*arm_movsi_insn}
     (nil))

(insn 30 24 27 (set (reg/f:SI 11 fp)
        (plus:SI (reg/f:SI 11 fp)
            (const_int 36 [0x24]))) 4 {*arm_addsi3}
     (nil))

despite the blockage.