Gimpel lowering question.

[Michael Eager]

I have a small test case which generates poor quality code on my target.
Here is the original:

   if (cond1 == 2048 || cond2 == 8)
     {
       x = x + y;
     }
   return x;

This ends up generating a series of instructions to compute a flag with
the result of the condition followed by a single compare with zero and
a jump.  Better code would be two compares and two jumps.

The gimple is

   _1 = cond1 == 2048;
   _2 = cond2 == 8;
   _3 = _1 | _2;
   if (_3 != 0) goto <D.1464>; else goto <D.1465>;
...

so this poor code sequence is essentially a correct translation.

On MIPS, for the same test case, the gimple is different:

   if (cond1 == 2048) goto <D.1491>; else goto <D.1493>;
   <D.1493>:
   if (cond2 == 8) goto <D.1491>; else goto <D.1492>;
   <D.1491>:
...

which generates the better code sequence.

Can someone give me a pointer where to find where the lowering
pass decides to break up a condition into multiple tests?  Is
there a target configuration option which I have overlooked or
maybe set incorrectly?

-- 
Michael Eager    eager@eagerm.com
1960 Park Blvd., Palo Alto, CA 94306