[Bug rtl-optimization/128251] [14/15/16/17 Regression] ICE at O2: in curr_insn_transform, at lra-constraints.cc:4885

[ubizjak at gmail dot com via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=128251

--- Comment #3 from Uroš Bizjak <ubizjak at gmail dot com> ---
An interesting observation: when eliminating argp in:

(insn 7 6 8 2 (set (reg:CCGOC 17 flags)
        (compare:CCGOC (reg/f:DI 16 argp)
            (const_int 0 [0]))) "pr128251.c":8:9 12 {*cmpdi_ccno_1}
     (nil))

LRA creates:

(insn 7 6 8 2 (set (reg:CCGOC 17 flags)
        (compare:CCGOC (plus:DI (reg/f:DI 16 argp)
                (const_int 16 [0x10]))
            (const_int 0 [0]))) "pr128251.c":8:9 24 {*cmpdi_plus_1}
     (nil))

which by luck matches valid instruction.