On Fri, Dec 2, 2011 at 8:28 PM, Jakub Jelinek <ja...@redhat.com> wrote:
> On Fri, Dec 02, 2011 at 02:27:40PM +0100, Richard Guenther wrote:
>> This change seems wrong. We are turning valid gimple
>>
>> # DEBUG D#2 => transfer.0 [with addres taken]
>>
>> into invalid one
>>
>> # DEBUG D#2 => transfer.0 [without address taken]
>>
>> once you update that stmt with update_stmt you'll get an SSA operand
>> for transfer.0 which is not in SSA form because you fail to rewrite it
>> into.
>>
>> Why do this in remove_unused_locals and not in update_address_taken?
>> Or, why do it at all?
>>
>> I have a SSA operand checking patch that catches this now ...
>
> Here is a fix for that. Instead of clearing TREE_ADDRESSABLE for
> unreferenced vars we allow them in target_for_debug_bind if they aren't
> referenced vars (thus we don't risk mixing VALUE tracking with the
> old style REG_EXPR/MEM_EXPR tracking of these variables).
>
> Bootstrapped/regtested on x86_64-linux and i686-linux, ok for trunk?
>
> 2011-12-02 Jakub Jelinek <ja...@redhat.com>
>
> PR debug/50317
> * tree-ssa.c (target_for_debug_bind): Also allow is_gimple_reg_type
> vars that aren't referenced.
> (tree-ssa-live.c (remove_unused_locals): Don't clear TREE_ADDRESSABLE
> of unreferenced local vars.
> * cfgexpand.c (expand_debug_expr): For DEBUG_IMPLICIT_PTR allow also
> TREE_ADDRESSABLE vars that satisfy target_for_debug_bind.
>
> --- gcc/tree-ssa.c.jj 2011-11-29 08:58:52.000000000 +0100
> +++ gcc/tree-ssa.c 2011-12-02 15:04:03.494148642 +0100
> @@ -264,7 +264,12 @@ target_for_debug_bind (tree var)
> return NULL_TREE;
>
> if (!is_gimple_reg (var))
> - return NULL_TREE;
> + {
> + if (is_gimple_reg_type (TREE_TYPE (var))
> + && referenced_var_lookup (cfun, DECL_UID (var)) == NULL_TREE)
> + return var;
> + return NULL_TREE;
> + }
With referenced-vars going away now I am running into the above use of
referenced-vars again. So the above tries to increase the set of tracked
"registers" by noting that unused non-registers that might have become
registers are supposed to be tracked anyway. But we do _not_ want to
have used non-register (but register type) variables tracked because we
do not track aliases? Or because that would be prohibitively expensive?
That is, why is
Index: tree-ssa.c
===================================================================
--- tree-ssa.c (revision 190031)
+++ tree-ssa.c (working copy)
@@ -259,13 +259,9 @@ target_for_debug_bind (tree var)
if (DECL_IGNORED_P (var))
return NULL_TREE;
- if (!is_gimple_reg (var))
- {
- if (is_gimple_reg_type (TREE_TYPE (var))
- && referenced_var_lookup (cfun, DECL_UID (var)) == NULL_TREE)
- return var;
- return NULL_TREE;
- }
+ /* var-tracking only tracks registers. */
+ if (!is_gimple_reg_type (TREE_TYPE (var)))
+ return NULL_TREE;
return var;
}
not what we want (minus dealing with fallout of having mixed SSA / non-SSA
after something makes var suitable for renaming into SSA form)?
Richard.
> return var;
> }
> --- gcc/tree-ssa-live.c.jj 2011-12-02 01:52:27.000000000 +0100
> +++ gcc/tree-ssa-live.c 2011-12-02 15:04:59.601816335 +0100
> @@ -814,15 +814,7 @@ remove_unused_locals (void)
> bitmap_set_bit (global_unused_vars, DECL_UID (var));
> }
> else
> - {
> - /* For unreferenced local vars drop TREE_ADDRESSABLE
> - bit in case it is referenced from debug stmts. */
> - if (DECL_CONTEXT (var) == current_function_decl
> - && TREE_ADDRESSABLE (var)
> - && is_gimple_reg_type (TREE_TYPE (var)))
> - TREE_ADDRESSABLE (var) = 0;
> - continue;
> - }
> + continue;
> }
> else if (TREE_CODE (var) == VAR_DECL
> && DECL_HARD_REGISTER (var)
> --- gcc/cfgexpand.c.jj 2011-12-02 01:52:27.000000000 +0100
> +++ gcc/cfgexpand.c 2011-12-02 15:24:37.982327507 +0100
> @@ -3325,7 +3325,8 @@ expand_debug_expr (tree exp)
> if ((TREE_CODE (TREE_OPERAND (exp, 0)) == VAR_DECL
> || TREE_CODE (TREE_OPERAND (exp, 0)) == PARM_DECL
> || TREE_CODE (TREE_OPERAND (exp, 0)) == RESULT_DECL)
> - && !TREE_ADDRESSABLE (TREE_OPERAND (exp, 0)))
> + && (!TREE_ADDRESSABLE (TREE_OPERAND (exp, 0))
> + || target_for_debug_bind (TREE_OPERAND (exp, 0))))
> return gen_rtx_DEBUG_IMPLICIT_PTR (mode, TREE_OPERAND (exp, 0));
>
> if (handled_component_p (TREE_OPERAND (exp, 0)))
> @@ -3337,7 +3338,8 @@ expand_debug_expr (tree exp)
> if ((TREE_CODE (decl) == VAR_DECL
> || TREE_CODE (decl) == PARM_DECL
> || TREE_CODE (decl) == RESULT_DECL)
> - && !TREE_ADDRESSABLE (decl)
> + && (!TREE_ADDRESSABLE (decl)
> + || target_for_debug_bind (decl))
> && (bitoffset % BITS_PER_UNIT) == 0
> && bitsize > 0
> && bitsize == maxsize)
>
>
> Jakub
