Re: [PATCH] VRP: don't assume strict overflow semantics when checking if a loop wraps

2014-11-27 Thread Richard Biener
On Fri, Nov 21, 2014 at 2:32 PM, Patrick Palka wrote: > On Fri, Nov 21, 2014 at 7:18 AM, Richard Biener > wrote: >> On Fri, Nov 21, 2014 at 12:29 PM, Patrick Palka wrote: >>> When adjusting the value range of an induction variable using SCEV, VRP >>> calls scev_probably_wraps_p() with use_overfl

Re: [PATCH] VRP: don't assume strict overflow semantics when checking if a loop wraps

2014-11-21 Thread Patrick Palka
On Fri, Nov 21, 2014 at 7:18 AM, Richard Biener wrote: > On Fri, Nov 21, 2014 at 12:29 PM, Patrick Palka wrote: >> When adjusting the value range of an induction variable using SCEV, VRP >> calls scev_probably_wraps_p() with use_overflow_semantics=true. This >> parameter set to true makes scev_p

Re: [PATCH] VRP: don't assume strict overflow semantics when checking if a loop wraps

2014-11-21 Thread Richard Biener
On Fri, Nov 21, 2014 at 12:29 PM, Patrick Palka wrote: > When adjusting the value range of an induction variable using SCEV, VRP > calls scev_probably_wraps_p() with use_overflow_semantics=true. This > parameter set to true makes scev_probably_wraps_p() assume that signed > induction variables ne

[PATCH] VRP: don't assume strict overflow semantics when checking if a loop wraps

2014-11-21 Thread Patrick Palka
When adjusting the value range of an induction variable using SCEV, VRP calls scev_probably_wraps_p() with use_overflow_semantics=true. This parameter set to true makes scev_probably_wraps_p() assume that signed induction variables never wrap, so for these variables it always returns false (when s