https://gcc.gnu.org/bugzilla/show_bug.cgi?id=85376
Jakub Jelinek <jakub at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
CC| |jakub at gcc dot gnu.org
--- Comment #6 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
The bug seems to be introduced during cse_local, before that we have:
(insn 28 26 31 2 (parallel [
(set (reg:CCZ 17 flags)
(compare:CCZ (reg:SI 188)
(const_int 0 [0])))
(set (reg:SI 93 [ _13 ])
(ctz:SI (reg:SI 188)))
]) "pr85376.c":12 735 {*bsfsi_1}
(expr_list:REG_DEAD (reg:SI 188)
(expr_list:REG_UNUSED (reg:SI 93 [ _13 ])
(expr_list:REG_UNUSED (reg:CCZ 17 flags)
(nil)))))
...
(insn 55 54 56 2 (set (reg:SI 194 [ o ])
(const_int 32 [0x20])) "pr85376.c":14 86 {*movsi_internal}
(expr_list:REG_DEAD (reg/v:HI 91 [ o ])
(nil)))
(insn 56 55 57 2 (set (reg:QI 108 [ _26+1 ])
(const_int 0 [0])) "pr85376.c":14 88 {*movqi_internal}
(nil))
(insn 57 56 58 2 (parallel [
(set (reg:CC 17 flags)
(compare:CC (subreg:QI (reg:SI 194 [ o ]) 0)
(subreg:QI (reg:SI 104 [ _23 ]) 0)))
(set (reg:QI 195)
(minus:QI (subreg:QI (reg:SI 194 [ o ]) 0)
(subreg:QI (reg:SI 104 [ _23 ]) 0)))
]) "pr85376.c":14 294 {*subqi_3}
(expr_list:REG_DEAD (reg:SI 194 [ o ])
(expr_list:REG_DEAD (reg:SI 104 [ _23 ])
(nil))))
But cse_local changes that to:
(insn 56 54 57 2 (set (reg:QI 108 [ _26+1 ])
(const_int 0 [0])) "pr85376.c":14 88 {*movqi_internal}
(nil))
(insn 57 56 58 2 (parallel [
(set (reg:CC 17 flags)
(compare:CC (subreg:QI (reg:SI 93 [ _13 ]) 0)
(subreg:QI (reg:SI 104 [ _23 ]) 0)))
(set (reg:QI 195)
(minus:QI (subreg:QI (reg:SI 93 [ _13 ]) 0)
(subreg:QI (reg:SI 104 [ _23 ]) 0)))
]) "pr85376.c":14 294 {*subqi_3}
(expr_list:REG_DEAD (reg:SI 194 [ o ])
(expr_list:REG_DEAD (reg:SI 104 [ _23 ])
(nil))))
but pseudo 93 certainly isn't known to contain (const_int 32). I don't think
cse pass uses cselib though.
