[Bug rtl-optimization/37286] [4.4 regression] gfortran, trunk: ICE subst_stack_regs_pat, at reg-stack.c:1537

["ubizjak at gmail dot com" <gcc-bugzilla at gcc dot gnu dot org>]

------- Comment #2 from ubizjak at gmail dot com  2008-08-30 14:05 -------
Confirmed, uninitialized register [st(2)] happens in bb-reorder pass:

before bb-reorder we have:

;; Start of basic block ( 10 3 9 6) -> 11

;; lr  in        7 [sp] 8 [st] 9 [st(1)] 10 [st(2)] 20 [frame]
;; lr  use       7 [sp] 8 [st] 9 [st(1)] 10 [st(2)]
;; lr  def       3 [bx] 4 [si] 6 [bp] 7 [sp] 8 [st] 9 [st(1)] 17 [flags]
;; live  in      7 [sp] 8 [st] 9 [st(1)] 10 [st(2)] 20 [frame]

...

(insn:HI 70 69 71 11 pr37286.f90:46 (set (reg:DF 9 st(1) [80])
        (mult:DF (float_extend:DF (reg/v:SF 10 st(2) [orig:60 monte_temp ]
[60]))
            (reg:DF 9 st(1) [79]))) 756 {*fop_df_4_i387} (expr_list:REG_DEAD
(reg/v:SF 10 st(2) [orig:60 monte_temp ] [60])
        (nil)))

after bb-reorder pass we have in (bb 9):

;; Start of basic block ( 2) -> 9
;; bb 9 artificial_defs: { }
;; bb 9 artificial_uses: { u-1(6){ }u-1(7){ }}
;; lr  in        3 [bx] 4 [si] 6 [bp] 7 [sp] 20 [frame]
;; lr  use       3 [bx] 4 [si] 6 [bp] 7 [sp]
;; lr  def       0 [ax] 1 [dx] 2 [cx] 8 [st] 9 [st(1)] 10 [st(2)] 11 [st(3)] 12
[st(4)] 13 [st(5)] 14 [st(6)] 15 [st(7)] 17 [flags] 18 [fpsr] 19 [fpcr] 21 []
22 [] 23 [] 24 [] 25 [] 26 [] 27 [] 28 [] 29 [] 30 [] 31 [] 32 [] 33 [] 34 []
35 [] 36 [] 37 [] 38 [] 39 [] 40 [] 41 [] 42 [] 43 [] 44 [] 45 [] 46 [] 47 []
48 [] 49 [] 50 [] 51 [] 52 []
;; live  in      3 [bx] 4 [si] 6 [bp] 7 [sp] 20 [frame]
;; live  gen     8 [st] 9 [st(1)]
;; live  kill   

...

(insn 146 145 147 9 pr37286.f90:46 (set (reg:DF 9 st(1) [80])
        (mult:DF (float_extend:DF (reg/v:SF 10 st(2) [orig:60 monte_temp ]
[60]))
            (reg:DF 9 st(1) [79]))) 756 {*fop_df_4_i387} (expr_list:REG_DEAD
(reg/v:SF 10 st(2) [orig:60 monte_temp ] [60])
        (nil)))

reg-stack then chokes due to:

Basic block 2
Input stack: empty
  insn 7 input stack: empty
  insn 8 input stack: [ 8 ]
  insn 126 input stack: [ 8 9 ]
scanning new insn with uid = 172.
Expected live registers [ 8 9 ]
Output stack: [ 9 8 ]

Basic block 9
Input stack: empty
  insn 17 input stack: empty
  insn 18 input stack: empty
  insn 19 input stack: [ 9 ]
  insn 145 input stack: [ 9 8 ]
  insn 146 input stack: [ 9 8 ]
scanning new insn with uid = 173.

Please note that input stack of bb 9 and output stack of bb2 doesn't match.


-- 

ubizjak at gmail dot com changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |NEW
          Component|target                      |rtl-optimization
     Ever Confirmed|0                           |1
           Keywords|ra                          |
   Last reconfirmed|0000-00-00 00:00:00         |2008-08-30 14:05:31
               date|                            |


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=37286