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RE: [PATCH GCC]Simplify address expression in IVOPT



> -----Original Message-----
> From: gcc-patches-owner@gcc.gnu.org [mailto:gcc-patches-
> owner@gcc.gnu.org] On Behalf Of bin.cheng
> Sent: Monday, November 04, 2013 4:35 PM
> To: 'Richard Biener'
> Cc: GCC Patches
> Subject: RE: [PATCH GCC]Simplify address expression in IVOPT
> 
> 
> 
> > -----Original Message-----
> > From: Richard Biener [mailto:richard.guenther@gmail.com]
> > Sent: Wednesday, October 30, 2013 10:46 PM
> > To: Bin Cheng
> > Cc: GCC Patches
> > Subject: Re: [PATCH GCC]Simplify address expression in IVOPT
> >
> > On Tue, Oct 29, 2013 at 10:18 AM, bin.cheng <bin.cheng@arm.com> wrote:
> >
> > Hmm.  I think you want what get_inner_reference_aff does, using the
> > return value of get_inner_reference as starting point for
> determine_base_object.
> > And you don't want to restrict yourselves so much on what exprs to
> process,
> > but only exclude DECL_Ps.
> Did you mean I should pass all address expressions to
> get_inner_reference_aff except the one with declaration operand?
> I am a little confused here why DECL_Ps should be handled specially?
Seems
> it can be handled properly by the get_* function.  Anything important I
> missed?
> 
> > Just amend get_inner_reference_aff to return the tree base object.
> I found it's inappropriate to do this because: functions like
> get_inner_reference* only accept reference expressions, while base_object
> has to be computed for other kinds of expressions too.  Take gimple
> statement "a_1 = *ptr_1" as an example, the base passed to alloc_iv is
ptr_1;
> the base_object computed by determine_base_object is also ptr_1, which
> we can't rely on get_inner_reference* .
> 
> Also It seems the comment before determine_base_object might be
> inaccurate:
> " Returns a memory object to that EXPR points." which I think is " Returns
a
> pointer pointing to the main memory object to that EXPR points."
> Right?
> >
> > Note that this isn't really "simplifying" but rather lowering all
> addresses.
> >
> > The other changes in this patch are unrelated, right?
> Right, I should have named this message like "refine cost computation of
> expressions in IVOPT" just as the patch file.

Hi,
I updated the patch according to review comments.  Now it lowers all address
expressions except ones with DECL_P to get_inner_reference_aff, it also
computes base_object which is used later to ease determine_base_object.

Bootstrap and test on x86/x86_64/arm on going,  is it OK if tests pass?

Thanks.
bin

gcc/testsuite/ChangeLog
2013-11-05  Bin Cheng  <bin.cheng@arm.com>

	* gcc.dg/tree-ssa/loop-2.c: Refine check condition.
	* gcc.dg/tree-ssa/ivopt_infer_2.c: Ditto.
	* gcc.dg/tree-ssa/ivopt_mult_3.c: Ditto.

2013-11-05  Bin Cheng  <bin.cheng@arm.com>

	* tree-ssa-loop-ivopts.c (alloc_iv): Lower address expressions.
	(get_shiftadd_cost): Check equality using operand_equal_p.
	(force_expr_to_var_cost): Refactor the code.  Handle type
	conversion.
	(split_address_cost): Call force_expr_to_var_cost.
	* tree-affine.c (get_inner_reference_aff): Return base_addr.
	* tree-affine.h (get_inner_reference_aff): Change prototype.

Attachment: 3-ivopt-expr_cost-20131105.txt
Description: Text document


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