Re: Algoritmic Complexity Attacks and 2.4.20 the dcache code

David S. Miller
2003-05-30T08:48:39Z

From: Alex Riesen <alexander.riesen@synopsys.COM>
Date: Fri, 30 May 2003 10:59:01 +0200

static
int hash_3(int hi, int c)
{
return (hi + (c << 4) + (c >> 4)) * 11;
}

gcc-3.2.1 -O2 -march=pentium
...
It is not guaranteed to be this way on all architectures, of course.
But still - no multiplications.

Indeed, I'd missed this. GCC will emit the constant multiply
expansion unless the multiply cost is set VERY low.