Patchwork Fix PR middle-end/44993

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Submitter Eric Botcazou
Date July 28, 2010, 7:44 a.m.
Message ID <201007280944.52575.ebotcazou@adacore.com>
Download mbox | patch
Permalink /patch/60123/
State New
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Comments

Eric Botcazou - July 28, 2010, 7:44 a.m.
This is the bootstrap failure on SPARC64/Linux introduced by the fix for PR 
middle-end/44790, which was a bootstrap failure on IA-64/HP-UX introduced by 
the mem-ref2 merge.

The fix introduced a non-canonical expansion for MEM_REF via POINTER_PLUS_EXPR 
which bypasses checks for valid addresses in the SPARC back-end: 

  name = MEM[(struct
exp_ch3__make_predefined_primitive_specs__B_99__stream_op_tss_names___PAD
*)D.14526_1156 + 4294967296B];

is expanded into

        sethi   %hi(stream_op_tss_names.6060+4294967296), %l2
        or      %l2, %lo(stream_op_tss_names.6060+4294967296), %l2

which overflows since sethi is a 32-bit operator.

This can very likely happen for other back-ends as well so I think that the 
best approach is to fix PR middle-end/44790 more canonically.  The problem 
was that:

op0 = expand_expr (base, NULL_RTX, address_mode, EXPAND_NORMAL);

assumed that op0 was generated in address_mode; this isn't guaranteed so an 
explicit address conversion is required:

op0 = convert_memory_address_addr_space (address_mode, op0, as);


Bootstrapped/regtested on SPARC64/Linux, applied on the mainline as obvious.


2010-07-28  Eric Botcazou  <ebotcazou@adacore.com>

	PR middle-end/44790
	PR middle-end/44993
	* expr.c (expand_expr_real_1) <MEM_REF>: Revert latest change.  Make
	sure the base has address_mode before adding the offset.
H.J. Lu - Sept. 15, 2010, 5:27 a.m.
On Wed, Jul 28, 2010 at 12:44 AM, Eric Botcazou <ebotcazou@adacore.com> wrote:
> This is the bootstrap failure on SPARC64/Linux introduced by the fix for PR
> middle-end/44790, which was a bootstrap failure on IA-64/HP-UX introduced by
> the mem-ref2 merge.
>
> The fix introduced a non-canonical expansion for MEM_REF via POINTER_PLUS_EXPR
> which bypasses checks for valid addresses in the SPARC back-end:
>
>  name = MEM[(struct
> exp_ch3__make_predefined_primitive_specs__B_99__stream_op_tss_names___PAD
> *)D.14526_1156 + 4294967296B];
>
> is expanded into
>
>        sethi   %hi(stream_op_tss_names.6060+4294967296), %l2
>        or      %l2, %lo(stream_op_tss_names.6060+4294967296), %l2
>
> which overflows since sethi is a 32-bit operator.
>
> This can very likely happen for other back-ends as well so I think that the
> best approach is to fix PR middle-end/44790 more canonically.  The problem
> was that:
>
> op0 = expand_expr (base, NULL_RTX, address_mode, EXPAND_NORMAL);
>
> assumed that op0 was generated in address_mode; this isn't guaranteed so an
> explicit address conversion is required:
>
> op0 = convert_memory_address_addr_space (address_mode, op0, as);
>
>
> Bootstrapped/regtested on SPARC64/Linux, applied on the mainline as obvious.
>
>
> 2010-07-28  Eric Botcazou  <ebotcazou@adacore.com>
>
>        PR middle-end/44790
>        PR middle-end/44993
>        * expr.c (expand_expr_real_1) <MEM_REF>: Revert latest change.  Make
>        sure the base has address_mode before adding the offset.
>

This patch caused:

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=45670
Eric Botcazou - Sept. 15, 2010, 5:51 a.m.
> This patch caused:
>
> http://gcc.gnu.org/bugzilla/show_bug.cgi?id=45670

No, it didn't, it cannot cause a code size regression from GCC 4.5 since it 
reverted an incorrect change made on trunk only.  Start from 161906 please.
Andrew Pinski - Sept. 15, 2010, 5:53 a.m.
On Tue, Sep 14, 2010 at 10:51 PM, Eric Botcazou <ebotcazou@adacore.com> wrote:
> No, it didn't, it cannot cause a code size regression from GCC 4.5 since it
> reverted an incorrect change made on trunk only.  Start from 161906 please.

By the way I noticed iv-opts differences between 4.3 and 4.6.  So you
might want to consider IV-opts changes first.

-- Pinski
H.J. Lu - Oct. 31, 2010, 9:38 p.m.
On Tue, Sep 14, 2010 at 10:27 PM, H.J. Lu <hjl.tools@gmail.com> wrote:
> On Wed, Jul 28, 2010 at 12:44 AM, Eric Botcazou <ebotcazou@adacore.com> wrote:
>> This is the bootstrap failure on SPARC64/Linux introduced by the fix for PR
>> middle-end/44790, which was a bootstrap failure on IA-64/HP-UX introduced by
>> the mem-ref2 merge.
>>
>> The fix introduced a non-canonical expansion for MEM_REF via POINTER_PLUS_EXPR
>> which bypasses checks for valid addresses in the SPARC back-end:
>>
>>  name = MEM[(struct
>> exp_ch3__make_predefined_primitive_specs__B_99__stream_op_tss_names___PAD
>> *)D.14526_1156 + 4294967296B];
>>
>> is expanded into
>>
>>        sethi   %hi(stream_op_tss_names.6060+4294967296), %l2
>>        or      %l2, %lo(stream_op_tss_names.6060+4294967296), %l2
>>
>> which overflows since sethi is a 32-bit operator.
>>
>> This can very likely happen for other back-ends as well so I think that the
>> best approach is to fix PR middle-end/44790 more canonically.  The problem
>> was that:
>>
>> op0 = expand_expr (base, NULL_RTX, address_mode, EXPAND_NORMAL);
>>
>> assumed that op0 was generated in address_mode; this isn't guaranteed so an
>> explicit address conversion is required:
>>
>> op0 = convert_memory_address_addr_space (address_mode, op0, as);
>>
>>
>> Bootstrapped/regtested on SPARC64/Linux, applied on the mainline as obvious.
>>
>>
>> 2010-07-28  Eric Botcazou  <ebotcazou@adacore.com>
>>
>>        PR middle-end/44790
>>        PR middle-end/44993
>>        * expr.c (expand_expr_real_1) <MEM_REF>: Revert latest change.  Make
>>        sure the base has address_mode before adding the offset.
>>
>
> This patch caused:
>
> http://gcc.gnu.org/bugzilla/show_bug.cgi?id=45670
>

This also caused:

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=46252
Eric Botcazou - Nov. 2, 2010, 11:56 a.m.
> This also caused:
>
> http://gcc.gnu.org/bugzilla/show_bug.cgi?id=46252

Again, no, it didn't, it cannot cause a regression from GCC 4.5 since it 
reverted an incorrect change made on trunk only.

Patch

Index: expr.c
===================================================================
--- expr.c	(revision 162566)
+++ expr.c	(working copy)
@@ -8730,11 +8730,14 @@  expand_expr_real_1 (tree exp, rtx target
 	  base = build2 (BIT_AND_EXPR, TREE_TYPE (base),
 			 gimple_assign_rhs1 (def_stmt),
 			 gimple_assign_rhs2 (def_stmt));
+	op0 = expand_expr (base, NULL_RTX, VOIDmode, EXPAND_NORMAL);
+	op0 = convert_memory_address_addr_space (address_mode, op0, as);
 	if (!integer_zerop (TREE_OPERAND (exp, 1)))
-	  base = build2 (POINTER_PLUS_EXPR, TREE_TYPE (base),
-			 base, double_int_to_tree (sizetype,
-						   mem_ref_offset (exp)));
-	op0 = expand_expr (base, NULL_RTX, address_mode, EXPAND_SUM);
+	  {
+	    rtx off
+	      = immed_double_int_const (mem_ref_offset (exp), address_mode);
+	    op0 = simplify_gen_binary (PLUS, address_mode, op0, off);
+	  }
 	op0 = memory_address_addr_space (mode, op0, as);
 	temp = gen_rtx_MEM (mode, op0);
 	set_mem_attributes (temp, exp, 0);