[patch] Fix oversight in tuplification of DOM

[patch] Fix oversight in tuplification of DOM

[Eric Botcazou]

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Hi,

the attached testcase triggers an ICE when compiled at -O or above, on all the 
open branches.  This is a regression introduced with the tuplification.  The 
problem is that 2 ARRAY_RANGE_REFs are recognized as equivalent, although they 
don't have the same number of elements.  This is so because their type isn't 
taken into account by the hash equality function as it simply isn't recorded 
in initialize_hash_element (GIMPLE_SINGLE_RHS case).  Now in all the other 
cases it is recorded so this very likely is an oversight.

Tested on x86_64-suse-linux, OK for all branches?


2011-06-28  Eric Botcazou  <ebotcazou@adacore.com>

	* tree-ssa-dom.c (initialize_hash_element): Fix oversight.


2011-06-28  Eric Botcazou  <ebotcazou@adacore.com>

	* gnat.dg/opt17.ad[sb]: New test.


-- 
Eric Botcazou

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Index: tree-ssa-dom.c
===================================================================
--- tree-ssa-dom.c	(revision 175408)
+++ tree-ssa-dom.c	(working copy)
@@ -214,6 +214,7 @@ initialize_hash_element (gimple stmt, tr
         {
         case GIMPLE_SINGLE_RHS:
 	  expr->kind = EXPR_SINGLE;
+	  expr->type = TREE_TYPE (gimple_assign_lhs (stmt));
 	  expr->ops.single.rhs = gimple_assign_rhs1 (stmt);
 	  break;
         case GIMPLE_UNARY_RHS:

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-- { dg-do compile }
-- { dg-options "-O" }

package body Opt17 is

  function Func return S is
    V : String (1 .. 6);
  begin
    V (1 .. 3) := "ABC";
    return V (1 .. 5);
  end;

end Opt17;

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package Opt17 is

  subtype S is String (1 .. 5);

  function Func return S;

end Opt17;

Re: [patch] Fix oversight in tuplification of DOM

[Jeff Law]

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Hash: SHA1

On 06/28/11 14:36, Eric Botcazou wrote:
> Hi,
> 
> the attached testcase triggers an ICE when compiled at -O or above, on all the 
> open branches.  This is a regression introduced with the tuplification.  The 
> problem is that 2 ARRAY_RANGE_REFs are recognized as equivalent, although they 
> don't have the same number of elements.  This is so because their type isn't 
> taken into account by the hash equality function as it simply isn't recorded 
> in initialize_hash_element (GIMPLE_SINGLE_RHS case).  Now in all the other 
> cases it is recorded so this very likely is an oversight.
> 
> Tested on x86_64-suse-linux, OK for all branches?
> 
> 
> 2011-06-28  Eric Botcazou  <ebotcazou@adacore.com>
> 
> 	* tree-ssa-dom.c (initialize_hash_element): Fix oversight.
> 
> 
> 2011-06-28  Eric Botcazou  <ebotcazou@adacore.com>
> 
> 	* gnat.dg/opt17.ad[sb]: New test.
OK.
Jeff
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Re: [patch] Fix oversight in tuplification of DOM

[Hans-Peter Nilsson]

On Tue, 28 Jun 2011, Eric Botcazou wrote:
> Hi,
>
> the attached testcase triggers an ICE when compiled at -O or above, on all the
> open branches.  This is a regression introduced with the tuplification.  The
> problem is that 2 ARRAY_RANGE_REFs are recognized as equivalent, although they
> don't have the same number of elements.  This is so because their type isn't
> taken into account by the hash equality function as it simply isn't recorded
> in initialize_hash_element (GIMPLE_SINGLE_RHS case).  Now in all the other
> cases it is recorded so this very likely is an oversight.
>
> Tested on x86_64-suse-linux, OK for all branches?
>
>
> 2011-06-28  Eric Botcazou  <ebotcazou@adacore.com>
>
> 	* tree-ssa-dom.c (initialize_hash_element): Fix oversight.

This caused a regression on 4.4 for cris-elf (at least), see
PR49572.

brgds, H-P

Re: [patch] Fix oversight in tuplification of DOM

[Richard Guenther]

On Tue, Jun 28, 2011 at 10:36 PM, Eric Botcazou <ebotcazou@adacore.com> wrote:
> Hi,
>
> the attached testcase triggers an ICE when compiled at -O or above, on all the
> open branches.  This is a regression introduced with the tuplification.  The
> problem is that 2 ARRAY_RANGE_REFs are recognized as equivalent, although they
> don't have the same number of elements.  This is so because their type isn't
> taken into account by the hash equality function as it simply isn't recorded
> in initialize_hash_element (GIMPLE_SINGLE_RHS case).  Now in all the other
> cases it is recorded so this very likely is an oversight.
>
> Tested on x86_64-suse-linux, OK for all branches?

Oops.  This would also make two MEM-REFs equivalent which access
different amount of memory.

Ok.

Thanks,
Richard.

>
> 2011-06-28  Eric Botcazou  <ebotcazou@adacore.com>
>
>        * tree-ssa-dom.c (initialize_hash_element): Fix oversight.
>
>
> 2011-06-28  Eric Botcazou  <ebotcazou@adacore.com>
>
>        * gnat.dg/opt17.ad[sb]: New test.
>
>
> --
> Eric Botcazou
>

Re: [patch] Fix oversight in tuplification of DOM

[Eric Botcazou]

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> 2011-06-28  Eric Botcazou  <ebotcazou@adacore.com>
>
> 	* tree-ssa-dom.c (initialize_hash_element): Fix oversight.

As reported under PR tree-optimization/49572, using the type of the LHS like in 
the other cases leads to optimization regressions.  The attached patch changes 
this to use the type of RHS instead in the GIMPLE_SINGLE_RHS case.

Tested on x86_64-suse-linux, pre-approved by Richard in the PR, applied.


2011-06-30  Eric Botcazou  <ebotcazou@adacore.com>

	PR tree-optimization/49572
	* tree-ssa-dom.c (initialize_hash_element) <GIMPLE_SINGLE_RHS>: Use the
	type of the RHS instead of that of the LHS for the expression type.


-- 
Eric Botcazou

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Index: tree-ssa-dom.c
===================================================================
--- tree-ssa-dom.c	(revision 175621)
+++ tree-ssa-dom.c	(working copy)
@@ -208,13 +208,11 @@ initialize_hash_element (gimple stmt, tr
     {
       enum tree_code subcode = gimple_assign_rhs_code (stmt);
 
-      expr->type = NULL_TREE;
-
       switch (get_gimple_rhs_class (subcode))
         {
         case GIMPLE_SINGLE_RHS:
 	  expr->kind = EXPR_SINGLE;
-	  expr->type = TREE_TYPE (gimple_assign_lhs (stmt));
+	  expr->type = TREE_TYPE (gimple_assign_rhs1 (stmt));
 	  expr->ops.single.rhs = gimple_assign_rhs1 (stmt);
 	  break;
         case GIMPLE_UNARY_RHS: