Re: [PATCH PR71437]Prefer symbolic range bound if the var doesn't have useful range.

2017-01-26 Thread Richard Biener
On Wed, Jan 25, 2017 at 5:30 PM, Bin Cheng wrote: > Hi, > As analyzed in PR71437, it's a missed PRE issue due to missed jump threading, > and then due to inaccurate VRP information. In function > extract_range_for_var_from_comparison_expr, > we compute range for variable "a" under condition that

[PATCH PR71437]Prefer symbolic range bound if the var doesn't have useful range.

2017-01-25 Thread Bin Cheng
Hi, As analyzed in PR71437, it's a missed PRE issue due to missed jump threading, and then due to inaccurate VRP information. In function extract_range_for_var_from_comparison_expr, we compute range for variable "a" under condition that comparison like "a <= limit" is true. It extracts limit's