SSA-based dead-code elimination

Richard Henderson
Thu Aug 3 16:31:00 GMT 2000

On Wed, Aug 02, 2000 at 05:36:49PM -0400, Michael Meissner wrote:
> One such way would be to us an empty asm (which given it doesn't specify
> target and input arguments, should be treated as volatile):
> 	int i;
> 	for (i = 0; i < n; i++)
> 	  __asm__ ("");

Which we may happily unroll, so that you get all N nothings side by side.
No.  There is no way to generate a machine-independant empty loop.

Of course, the concept of a machine-independant delay loop is ludicrous.
You should just do the whole loop in assembly where you know what the
timing of the instructions are going to be.


More information about the Gcc-patches mailing list