re PR rtl-optimization/27671 (optimization error on pentium4-Linux with %, regression from gcc-4.1.0)

gcc/
	PR rtl-optimization/27671
	* simplify-rtx.c (simplify_relational_operation_1): Fix
	simplifications of (eq/ne (xor x y) y) and
	(eq/ne (xor x y) x).

gcc/testsuite/
	PR rtl-optimization/27671
	* gcc.c-torture/execute/pr27671-1.c: New.
	* gcc.dg/pr27671-2.c: Likewise.

From-SVN: r113955