------- Comment #12 from rguenther at suse dot de 2007-06-26 21:55 -------
Subject: Re: [4.3 Regression] attribute always_inline
-> sorry, unimplemented: recursive inlining
On Tue, 26 Jun 2007, pinskia at gcc dot gnu dot org wrote:
> I can find a testcase, if we change where we generate the promotion at the RTL
> expansion time, worse code.
> Simple testcase:
>
> int f(int b, char a)
> {
> if (b)
> a = 1;
> g(a);
> }
>
> You can see the difference by looking 3.4 vs 4.2's code generation :).
I have a hard time deciding if 3.4 or 4.1 is better:
3.4:
f:
pushl %ebp
movl %esp, %ebp
movl 8(%ebp), %edx
movzbl 12(%ebp), %eax
testl %edx, %edx
je .L2
movb $1, %al
.L2:
movsbl %al,%eax
movl %eax, 8(%ebp)
popl %ebp
jmp g
4.1 (same as 4.2):
f:
pushl %ebp
movl $1, %edx
movl %esp, %ebp
movl 8(%ebp), %ecx
movzbl 12(%ebp), %eax
testl %ecx, %ecx
je .L7
movl %edx, 8(%ebp)
popl %ebp
jmp g
.p2align 4,,7
.L7:
movsbl %al,%edx
movl %edx, 8(%ebp)
popl %ebp
jmp g
--
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=32492
