🚀 go-pugleaf

In article <9576:Nov1523:11:0990@kramden.acf.nyu.edu>
brnstnd@kramden.acf.nyu.edu (Dan Bernstein) writes:

| You want a specific example? Were you reading this group when somebody
| pointed out how Sun's optimizer couldn't produce even near-optimal code
| for a simple loop through an array? Matt pointed out that gcc did much
| better. gcc, however, will produce suboptimal code for
| 
|   for (j = 0;j < 100;j++)
|     a[i * j] = ...;
| 
| As you now understand, no optimizer will handle all cases. For any
| optimizer you show me, there exists array code that it can't convert
| into pointer code as well as possible. What matters in practice is that
| real optimizers trip up on such simple code. Even good Fortran
| optimizers don't do very well on moderately complex code.

GCC does do the optimization on the MIPS (providing you use strength
reduction).  I suspect the array a was an integer array, since the
Sparc does not have an integer multiplication, gcc internally turned
the thing into calling __mulsi3, which it no longer reconizes as a
multiply.
--
Michael Meissner	email: meissner@osf.org		phone: 617-621-8861
Open Software Foundation, 11 Cambridge Center, Cambridge, MA, 02142

Considering the flames and intolerance, shouldn't USENET be spelled ABUSENET?