2 Dec
2010
2 Dec
'10
11:47 a.m.
On Wed, Dec 1, 2010 at 9:42 PM, Chuck Guzis <cclist at sydex.com> wrote:
The Microsoft issue, I recall was with dead code
elimination. ?The C
expression
? ? ? ?while( C != 0);
could normally be eliminated if C was 0...
I have used the following in embedded code to tight-loop the CPU in
certain circumstances, intentionally requiring a reset of the
processor to escape...
for (;;)
;
I suppose a good optimizer would know that you really meant to do that
and should produce something resembling the following
$1: JMP $1
...but I certainly wouldn't want that statement optimized out entirely.
The beauty of a good optimizer is that it allows one
to write legible
code that still turns in good performance.
Indeed.
The horror of a bad optimizer (and I _have_ seen this) is that it
introduces bugs that vanish when the optimizer is turned off.
-ethan