Re: [patch] Performance patch for MIPS conditional move in expr.c

[Steve Ellcey <sellcey at mips dot com>]

On Wed, 2012-11-14 at 11:15 -0800, Andrew Pinski wrote:

> Do you have a testcase?  As I added expand_cond_expr_using_cmove, I
> think this is the correct fix.
> 
> Thanks,
> Andrew Pinski

Here is a cutdown test case that I have been compiling with -O3, if you
compare with and without my patch you will see fewer 'andi' instructions
with 0xffff are generated after my patch is applied.

Steve Ellcey
sellcey@mips.com

unsigned short foo(unsigned short a1, unsigned short a2)
{
  unsigned short i, x;
  for (i = 0; i < 8; i++) {
    x = (a1 & 1) ^ (a2 & 1);
    a1 >>= 1;
    if (x == 1) a2 ^= 0x2006;
    a2 >>= 1;
    if (x == 1) a2 |= 0x8800;
    else        a2 &= 0x77ff;
  }
  return a2;
}