[Bug rtl-optimization/27468] sign-extending Alpha instructions not exploited

[pinskia at gcc dot gnu dot org]

------- Comment #1 from pinskia at gcc dot gnu dot org  2006-05-07 18:35 -------
For abs, we do get a difference in the RTL:

(insn 32 11 16 2 (set (subreg:SI (reg:DI 73) 0)
        (subreg:SI (reg:DI 72) 0)) -1 (nil)
    (expr_list:REG_DEAD (reg:DI 72)
        (nil)))

(note 16 32 31 2 NOTE_INSN_FUNCTION_END)

(insn 31 16 19 2 (set (reg:DI 73)
        (sign_extend:DI (subreg:SI (reg:DI 73) 0))) 1 {*extendsidi2_1} (nil)
    (nil))

--------- TO;
(insn 12 11 16 2 (set (reg:DI 73)
        (sign_extend:DI (subreg:SI (reg:DI 72) 0))) 1 {*extendsidi2_1}
(insn_list:REG_DEP_TRUE 11 (nil))
    (expr_list:REG_DEAD (reg:DI 72)
        (nil)))

(note 16 12 19 2 NOTE_INSN_FUNCTION_END)


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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=27468