Re: [PATCH] Fix PR tree-optimization/78598 - tree-ssa-loop-prefetch.c:835:16: runtime error: signed integer overflow

2016-12-01 Thread Richard Biener
On Thu, Dec 1, 2016 at 1:49 PM, Markus Trippelsdorf wrote: > Using bootstrap-ubsan gcc to build mplayer shows: > > tree-ssa-loop-prefetch.c:835:16: runtime error: signed integer overflow: > 288230376151711743 * 64 cannot be represented in type 'long int' > > Here signed und unsigned integers are m

[PATCH] Fix PR tree-optimization/78598 - tree-ssa-loop-prefetch.c:835:16: runtime error: signed integer overflow

2016-12-01 Thread Markus Trippelsdorf
Using bootstrap-ubsan gcc to build mplayer shows: tree-ssa-loop-prefetch.c:835:16: runtime error: signed integer overflow: 288230376151711743 * 64 cannot be represented in type 'long int' Here signed und unsigned integers are mixed in a division resulting in bogus results: (-83 + 64ULL -1) / 64UL