[PATCH] reorganize simplify_const_relational_operation

[David Edelsohn]

	This patch breaks bootstrap on AIX.

enum
{
  CR_EQ = 1,
  CR_LT = 2,
  CR_GT = 4,
  CR_LTU = 8,
  CR_GTU = 16
};

CR_EQ, CR_LT, and CR_GT are Condition Register fields on PowerPC and those
names already in use.  The enum turns into:

enum
{
  0x20000000 = 1,
  0x80000000 = 2,
  0x40000000 = 4,
  CR_LTU = 8,
  CR_GTU = 16
};

I don't think we can change AIX.  Can we at least #undef the names before
the enum in simplify-rtx.c?

Thanks, David