[Bug target/30961] [4.2/4.3 regression] redundant reg/mem stores/moves

[hjl at lucon dot org]

------- Comment #11 from hjl at lucon dot org  2007-05-12 22:27 -------
find_reloads gets

(insn:HI 6 3 10 2 x.i:2 (set (reg:SF 21 xmm0 [orig:58 <result> ] [58])
        (subreg:SF (reg/v:SI 5 di [orig:59 in ] [59]) 0)) 90 {*movsf_1}
(insn_list:REG_DEP_TRUE 2 (nil))
    (expr_list:REG_DEAD (reg/v:SI 5 di [orig:59 in ] [59])
        (nil)))

But this pattern is valid since inter-unit move isn't allowed. It then
tries

(insn:HI 6 3 10 2 x.i:2 (set (reg:SF 22 xmm1)
        (subreg:SF (reg/v:SI 5 di [orig:59 in ] [59]) 0)) 90 {*movsf_1}
(insn_list:REG_DEP_TRUE 2 (nil))
    (expr_list:REG_DEAD (reg/v:SI 5 di [orig:59 in ] [59])
        (nil)))

This pattern isn't allowed either for the same reason. But gen_reload
emits

(insn 22 3 23 2 x.i:2 (set (mem/c:SF (plus:DI (reg/f:DI 7 sp)
                (const_int -4 [0xfffffffffffffffc])) [0 S4 A8])
        (reg:SF 5 di)) 90 {*movsf_1} (nil)
    (nil))

(insn 23 22 6 2 x.i:2 (set (reg:SF 22 xmm1)
        (mem/c:SF (plus:DI (reg/f:DI 7 sp)
                (const_int -4 [0xfffffffffffffffc])) [0 S4 A8])) 90 {*movsf_1}
(
nil)
    (nil))


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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=30961