[Bug tree-optimization/21520] missing PRE opportunity with cast after cast

[pinskia at gcc dot gnu dot org]

------- Additional Comments From pinskia at gcc dot gnu dot org  2005-05-11 
22:04 -------
And we save an  instruction on x86 (both with -O2 -fomit-frame-pointer)
before:
        movl    4(%esp), %edx
        movb    $1, %al
        testl   %edx, %edx
        je      .L4
        movzbl  (%edx), %eax
.L4:
        movsbl  %al,%eax
        ret
after:
        movl    4(%esp), %edx
        movl    $1, %eax
        testl   %edx, %edx
        je      .L10
        movsbl  (%edx),%eax
.L10:
        ret

-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=21520