[Bug middle-end/50632] [4.7 Regression] FAIL: gcc.dg/pr50132.c

[rth at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=50632

Richard Henderson <rth at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |ASSIGNED
   Last reconfirmed|                            |2011-10-06
         AssignedTo|unassigned at gcc dot       |rth at gcc dot gnu.org
                   |gnu.org                     |
   Target Milestone|---                         |4.7.0
     Ever Confirmed|0                           |1

--- Comment #2 from Richard Henderson <rth at gcc dot gnu.org> 2011-10-06 
19:04:34 UTC ---
The problem is that the CSA pass is dropping a note when combining


(insn 13 12 16 3 (parallel [
            (set (reg/f:DI 7 sp)
                (plus:DI (reg/f:DI 7 sp)
                    (const_int 16 [0x10])))
            (clobber (reg:CC 17 flags))
        ]) z.c:9 254 {*adddi_1}
     (expr_list:REG_ARGS_SIZE (const_int 0 [0])
        (nil)))

(insn/f 31 30 35 4 (parallel [
            (set (reg/f:DI 7 sp)
                (plus:DI (reg/f:DI 7 sp)
                    (const_int 8 [0x8])))
            (clobber (reg:CC 17 flags))
            (clobber (mem:BLK (scratch) [0 A8]))
        ]) z.c:10 -1
     (expr_list:REG_CFA_ADJUST_CFA (set (reg/f:DI 7 sp)
            (plus:DI (reg/f:DI 7 sp)
                (const_int 8 [0x8])))
        (nil)))

to

(insn/f 31 30 35 3 (parallel [
            (set (reg/f:DI 7 sp)
                (plus:DI (reg/f:DI 7 sp)
                    (const_int 24 [0x18])))
            (clobber (reg:CC 17 flags))
            (clobber (mem:BLK (scratch) [0 A8]))
        ]) z.c:10 921 {pro_epilogue_adjust_stack_di_add}
     (expr_list:REG_UNUSED (reg:CC 17 flags)
        (expr_list:REG_CFA_ADJUST_CFA (set (reg/f:DI 7 sp)
                (plus:DI (reg/f:DI 7 sp)
                    (const_int 8 [0x8])))
            (nil))))

We've lost the REG_ARGS_SIZE note, which also affects the CFA
given that we're not using a frame pointer.