Jeff Law <law@xxxxxxxxxx> writes:
> The tail merging code in the RTL optimizers might pick this stuff up
> and Tom's work on block merging might as well. It'd be worth
> looking into why they aren't triggering.
Hmm, actually testing with a recent gcc snapshot, it _is_ merging the
two if-blocks:
int a, b, c, d, e, f;
extern void foo ();
void t (int x)
{
if (x==1) { a=b; c=d; e=f; foo(); }
if (x==2) { a=b; c=d; e=f; foo(); }
}
=>
t:
cmpl $1, %edi
je .L4
cmpl $2, %edi
je .L4
rep
ret
.L4:
movl b(%rip), %eax
movl %eax, a(%rip)
movl d(%rip), %eax
movl %eax, c(%rip)
movl f(%rip), %eax
movl %eax, e(%rip)
xorl %eax, %eax
jmp foo
...
.ident "GCC: (Debian 20110924-1) 4.7.0 20110924 (experimental) [trunk revision 179143]"
-Miles
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Quotation, n. The act of repeating erroneously the words of another. The words
erroneously repeated.
