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Re: [PATCH] Fix PR83418


On December 14, 2017 4:43:42 PM GMT+01:00, Jeff Law <law@redhat.com> wrote:
>On 12/14/2017 01:54 AM, Richard Biener wrote:
>> 
>> IVOPTs (at least) leaves unfolded stmts in the IL and VRP
>overzealously
>> asserts they cannot happen.
>> 
>> Bootstrap and regtest running on x86_64-unknown-linux-gnu.
>> 
>> Richard.
>> 
>> 2017-12-14  Richard Biener  <rguenther@suse.de>
>> 
>> 	PR tree-optimization/83418
>> 	* vr-values.c
>(vr_values::extract_range_for_var_from_comparison_expr):
>> 	Instead of asserting we don't get unfolded comparisons deal with
>> 	them.
>> 
>> 	* gcc.dg/torture/pr83418.c: New testcase.
>I think this also potentially affects dumping.  I've seen the dumper
>crash trying to access a INTEGER_CST where we expected to find an
>SSA_NAME while iterating over a statement's operands.
>
>I haven't submitted the workaround because I hadn't tracked down the
>root cause to verify something deeper isn't wrong.

Yes, I've seen this as well, see my comment in the PR. The issue is that DOM calls VRP analyze (and dump) routines with not up to date operands during optimize_stmt. 

Richard. 

>Jeff


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