cygwin source question

Mon Jan 22 10:42:00 GMT 2007

On 22 January 2007 08:19, Yitzchak Scott-Thoennes wrote:
>> Some people prefer (expr) ? 1 : 0, which looks a lot worse to me than
> !!(expr). 
>
 Compiles to the exact same thing at -O0 and at -O2, as it happens...
/tmp $ gcc -x c -S -o - -
int foo (int argc)
{
 return (argc == 23) ? 1 : 0;
}
int bar (int argc)
{
 return !!(argc == 23);
}
 .file ""
 .text
.globl _foo
 .def _foo; .scl 2; .type 32; .endef
_foo:
 pushl %ebp
 movl %esp, %ebp
 cmpl 23,ドル 8(%ebp)
 sete %al
 movzbl %al, %eax
 popl %ebp
 ret
.globl _bar
 .def _bar; .scl 2; .type 32; .endef
_bar:
 pushl %ebp
 movl %esp, %ebp
 cmpl 23,ドル 8(%ebp)
 sete %al
 movzbl %al, %eax
 popl %ebp
 ret
@_______. .
( /"\
 ||--||(___)
 '" '"'---'
/tmp $ gcc -O0 -x c -S -o - -
int foo (int argc)
{
 return (argc == 23) ? 1 : 0;
}
int bar (int argc)
{
 return !!(argc == 23);
}
 .file ""
 .text
.globl _foo
 .def _foo; .scl 2; .type 32; .endef
_foo:
 pushl %ebp
 movl %esp, %ebp
 cmpl 23,ドル 8(%ebp)
 sete %al
 movzbl %al, %eax
 popl %ebp
 ret
.globl _bar
 .def _bar; .scl 2; .type 32; .endef
_bar:
 pushl %ebp
 movl %esp, %ebp
 cmpl 23,ドル 8(%ebp)
 sete %al
 movzbl %al, %eax
 popl %ebp
 ret
@_______. .
( /"\
 ||--||(___)
 '" '"'---'
/tmp $ gcc -O2 -x c -S -o - -
int foo (int argc)
{
 return (argc == 23) ? 1 : 0;
}
int bar (int argc)
{
 return !!(argc == 23);
}
 .file ""
 .text
 .p2align 4,,15
.globl _foo
 .def _foo; .scl 2; .type 32; .endef
_foo:
 pushl %ebp
 xorl %eax, %eax
 movl %esp, %ebp
 cmpl 23,ドル 8(%ebp)
 popl %ebp
 sete %al
 ret
 .p2align 4,,15
.globl _bar
 .def _bar; .scl 2; .type 32; .endef
_bar:
 pushl %ebp
 xorl %eax, %eax
 movl %esp, %ebp
 cmpl 23,ドル 8(%ebp)
 popl %ebp
 sete %al
 ret
@_______. .
( /"\
 ||--||(___)
 '" '"'---'
/tmp $
 ... so no reason not to choose whichever you like the best.
 cheers,
 DaveK
-- 
Can't think of a witty .sigline today....
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