2018-04-20  Richard Biener <rguenther@suse.de>

	PR middle-end/85475
	* match.pd ((X * CST) * Y -> (X * Y) * CST): Avoid exponential
	complexity by forcing a single use of the multiply operand.

	* gcc.dg/torture/pr85475.c: New testcase.

From-SVN: r259519