[PATCH] Fix PR92462

[Jakub Jelinek]

On Mon, Nov 18, 2019 at 10:44:14AM +0100, Richard Biener wrote:
> The following adjusts the find_base_{term,value} heuristic when
> looking through ANDs to the case where it is obviously not
> aligning a base (when the LSB is set).

What is specific about the LSB?  I mean & 2 is obviously not an aligning
AND either.  Shouldn't we recurse only if the CONST_INT_P operand has
some set bits followed by clear bits, i.e. after the != 0 check
compute ctz_hwi and verify that INTVAL >> ctz == -1?

> Bootstrapped and tested on x86_64-unknown-linux-gnu, applied.
> 
> Richard.
> 
> 2019-11-18  Richard Biener  <rguenther@suse.de>
> 
> 	PR rtl-optimization/92462
> 	* alias.c (find_base_term): Restrict the look through ANDs.
> 	(find_base_value): Likewise.

	Jakub