re PR tree-optimization/90213 (UBSAN: signed integer overflow: -5621332293356458048 * 8 cannot be represented in type 'long int')

2019-04-24  Richard Biener  <rguenther@suse.de>

	PR middle-end/90213
	* gimple-fold.c (fold_const_aggregate_ref_1): Do multiplication
	by size and BITS_PER_UNIT on poly-wide-ints.

From-SVN: r270570