PR tree-optimization/90078
	* tree-ssa-loop-ivopts.c (comp_cost::operator +,-,+=,-+,/=,*=): Add
	checks for infinite_cost overflow.

	gcc/testsuite
	* gcc/testsuite/g++.dg/tree-ssa/pr90078.C: New test.

	Also fix typo in ChangeLog entry for revision 270499.

From-SVN: r270500