regalloc-2.cs

//
// Idealy, we would fold the operations from a...h into one long xor chain,
// we could then commute the xor operation.
//
// More realisticly, we should assign each of a...h to one reg, rather than making
// the two swap between two registers:
// 	 (stind.i4 regvar[%edi] (xor (ldind.i4 regoffset[-0x18(%ebp)]) iconst[1]))
//	 (stind.i4 regvar[%esi] (xor (ldind.i4 regvar[%edi]) iconst[2]))
//	 (stind.i4 regvar[%edi] (xor (ldind.i4 regvar[%esi]) iconst[3]))
//	 (stind.i4 regvar[%esi] (xor (ldind.i4 regvar[%edi]) iconst[4]))
//

class T {
	static void Main ()
	{
		int j = 0, k = 0, l = 0;
		for (int i = 0; i < 50000000; i ++) {
			int a = i ^ 1;
			int b = a ^ 2;
			int c = b ^ 3;
			int d = c ^ 4;
			int e = d ^ 5;
			int f = e ^ 6;
			int g = f ^ 7;
			int h = g ^ 8;
			
			j ^= h;
			k ^= h + 1;
			l ^= h & 5;
			
			j ^= l;
			k ^= k + 1;
			l ^= j & 5;
			
			j ^= l;
			k ^= k + 1;
			l ^= j & 5;
		}
	}
}