[Bug target/118739] [15 Regression] wrong code at -O{s,3} with "-fno-tree-forwprop -fno-tree-vrp" on x86_64-linux-gnu

[ubizjak at gmail dot com via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=118739

--- Comment #5 from Uroš Bizjak <ubizjak at gmail dot com> ---
So, we have:

Trying 15 -> 16:
   15: flags:CCNO=cmp(r115:SI,0)
      REG_DEAD r115:SI
   16: r106:QI=flags:CCNO>0
Successfully matched this instruction:
(set (reg:CCNO 17 flags)
    (compare:CCNO (reg:SI 115 [ _1 ])
        (const_int 0 [0])))
Successfully matched this instruction:
(set (reg:QI 106 [ _37 ])
    (subreg:QI (reg:SI 115 [ _1 ]) 0))

Which I don't think is correct.