[Bug middle-end/22051] [4.0/4.1 regression] Wrong code for function pointer comparision during optimization

[tausq at debian dot org]

------- Additional Comments From tausq at debian dot org  2005-06-13 16:23 
-------
this is what you get with gcc-3.3:

.LC0:
.stringz"main"
        .section        .rodata.cst4,"aM",@progbits,4
        .align 4
.LC1:
        .word   P%main
[...]
        ldil LR'.LC0,%r25
        ldi -1,%r4
        bl dlsym,%r2
        ldo RR'.LC0(%r25),%r25
        comib,= 0,%r28,.L1
        copy %r28,%r26
        bl __canonicalize_funcptr_for_compare,%r2
        nop
        ldil LR'.LC1,%r19
        copy %r28,%r4
        bl __canonicalize_funcptr_for_compare,%r2
        ldw RR'.LC1(%r19),%r26
        comclr,= %r28,%r4,%r4
        ldi 1,%r4
.L1:
        copy %r4,%r28


And with gcc-4.0, you get instead:
.LC0:
.stringz"main"
        .section        .rodata.cst4,"aM",@progbits,4
        .align 4
.LC1:
        .word   P%main
[...]
        ldil LR'.LC0,%r25
        bl dlsym,%r2
        ldo RR'.LC0(%r25),%r25
        movb,= %r28,%r20,.L4
        ldi -1,%r19
        ldil LR'.LC1,%r28
        ldw RR'.LC1(%r28),%r19
        comclr,= %r19,%r20,%r19
        ldi 1,%r19
.L4:
        copy %r19,%r28



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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=22051