[Bug rtl-optimization/118623] [12/13/14/15 regression] Miscompile with -O2/3 and -O0/1

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=118623

--- Comment #7 from Richard Biener <rguenth at gcc dot gnu.org> ---
RTL if-conversion is it, -fno-if-conversion fixes it.

CE1 does

IF-THEN-ELSE-JOIN block found, pass 1, test 2, then 3, else 4, join 5
scanning new insn with uid = 33.
scanning new insn with uid = 34.
scanning new insn with uid = 35.
scanning new insn with uid = 36.
if-conversion succeeded through noce_try_cmove_arith
deleting insn with uid = 4.
deleting block 4
Removing jump 12.
deleting insn with uid = 12.
deleting insn with uid = 14.
deleting block 3
Merging block 5 into block 2...
changing bb of uid 16
...