[Bug debug/66691] [5/6 Regression] ICE on valid code at -O3 with -g enabled in simplify_subreg, at simplify-rtx.c:5744

[ubizjak at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66691

Uroš Bizjak <ubizjak at gmail dot com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |vmakarov at gcc dot gnu.org

--- Comment #3 from Uroš Bizjak <ubizjak at gmail dot com> ---
In _.ira dump, we have:

(insn 146 144 147 21 (set (reg:HI 96 [ D.1574 ])
        (const_int 0 [0])) pr66691.c:42 88 {*movhi_internal}
     (expr_list:REG_EQUAL (const_int 0 [0])
        (nil)))

[...]

(debug_insn 148 147 30 21 (var_location:QI r (subreg:QI (reg:HI 96 [ D.1574 ])
0)) pr66691.c:42 -1
     (nil))

And in _.reload, we get invalid RTX when (const_int 0) propagates to
(debug_insn 148):

(note 146 144 429 21 NOTE_INSN_DELETED)

[...]

(debug_insn 148 147 30 21 (var_location:QI r (subreg:QI (const_int 0 [0]) 0))
pr66691.c:42 -1
     (nil))

Looks like LRA problem, adding CC.