* Restrict keyword doesn't work correctly in GCC 4.4
@ 2009-06-03 10:42 Bingfeng Mei
2009-06-03 10:53 ` Richard Guenther
0 siblings, 1 reply; 6+ messages in thread
From: Bingfeng Mei @ 2009-06-03 10:42 UTC (permalink / raw)
To: gcc
Hello,
I noticed that the restrict doesn't work fully on 4.4.0 (used to work on
our port based on 4.3 branch). The problem is that tree optimizer can do a
lot of optimization regarding pointer, e.g., at -O3. The alias set property
is not propagated accordingly.
Is the following RTL expansion correct? Both read and write address are
converted to a restrict pointer, but the both mem rtx have the same alias set (2).
;; *(int * restrict) (D.1768 + 4) = *(int * restrict) (D.1770 + 4);
(insn 56 55 57 tst.c:7 (set (reg:SI 124)
(mem:SI (plus:SI (reg:SI 103 [ D.1770 ])
(const_int 4 [0x4])) [2 S4 A32])) -1 (nil))
(insn 57 56 0 tst.c:7 (set (mem:SI (plus:SI (reg:SI 104 [ D.1768 ])
(const_int 4 [0x4])) [2 S4 A32])
(reg:SI 124)) -1 (nil))
The alias set property is copied from tree node:
<indirect_ref 0xf7f09d40
type <integer_type 0xf7f122f4 int sizes-gimplified public SI
size <integer_cst 0xf7f0f9d8 constant 32>
unit size <integer_cst 0xf7f0f7c4 constant 4>
align 32 symtab 0 alias set 2 canonical type 0xf7f122f4 precision 32 min <integer_cst 0xf7f0f984 -2147483648> max <integer_cst 0xf7f0f9a0 2147483647>
pointer_to_this <pointer_type 0xf7f18798>>
arg 0 <nop_expr 0xf7fc7400
type <pointer_type 0xf7fa6870 type <integer_type 0xf7f122f4 int>
sizes-gimplified public unsigned restrict SI size <integer_cst 0xf7f0f9d8 32> unit size <integer_cst 0xf7f0f7c4 4>
align 32 symtab 0 alias set -1 canonical type 0xf7fa6870>
arg 0 <plus_expr 0xf7fc95e8 type <integer_type 0xf7f12438 long unsigned int>
arg 0 <var_decl 0xf7fc4a6c D.1768>
arg 1 <integer_cst 0xf7fb7bec constant 4>
tst.c:7:5>
tst.c:7:5>
tst.c:7:5>
Is the RTL expansion wrong or the orginal tree node is constructed incorrectly?
Thanks,
Bingfeng Mei
Broadcom UK
^ permalink raw reply [flat|nested] 6+ messages in thread* Re: Restrict keyword doesn't work correctly in GCC 4.4 2009-06-03 10:42 Restrict keyword doesn't work correctly in GCC 4.4 Bingfeng Mei @ 2009-06-03 10:53 ` Richard Guenther 2009-06-03 11:02 ` Bingfeng Mei 0 siblings, 1 reply; 6+ messages in thread From: Richard Guenther @ 2009-06-03 10:53 UTC (permalink / raw) To: Bingfeng Mei; +Cc: gcc [-- Attachment #1: Type: text/plain, Size: 2335 bytes --] On Wed, Jun 3, 2009 at 12:41 PM, Bingfeng Mei <bmei@broadcom.com> wrote: > Hello, > I noticed that the restrict doesn't work fully on 4.4.0 (used to work on > our port based on 4.3 branch). The problem is that tree optimizer can do a > lot of optimization regarding pointer, e.g., at -O3. The alias set property > is not propagated accordingly. > > Is the following RTL expansion correct? Both read and write address are > converted to a restrict pointer, but the both mem rtx have the same alias set (2). > > ;; *(int * restrict) (D.1768 + 4) = *(int * restrict) (D.1770 + 4); restrict only works if there is a restrict qualified pointer decl in your source. I will re-implement restrict support completely for 4.5. You can try the attached hack which might help (but also cause weird effects ...). Richard. > (insn 56 55 57 tst.c:7 (set (reg:SI 124) > (mem:SI (plus:SI (reg:SI 103 [ D.1770 ]) > (const_int 4 [0x4])) [2 S4 A32])) -1 (nil)) > > (insn 57 56 0 tst.c:7 (set (mem:SI (plus:SI (reg:SI 104 [ D.1768 ]) > (const_int 4 [0x4])) [2 S4 A32]) > (reg:SI 124)) -1 (nil)) > > > The alias set property is copied from tree node: > <indirect_ref 0xf7f09d40 > type <integer_type 0xf7f122f4 int sizes-gimplified public SI > size <integer_cst 0xf7f0f9d8 constant 32> > unit size <integer_cst 0xf7f0f7c4 constant 4> > align 32 symtab 0 alias set 2 canonical type 0xf7f122f4 precision 32 min <integer_cst 0xf7f0f984 -2147483648> max <integer_cst 0xf7f0f9a0 2147483647> > pointer_to_this <pointer_type 0xf7f18798>> > > arg 0 <nop_expr 0xf7fc7400 > type <pointer_type 0xf7fa6870 type <integer_type 0xf7f122f4 int> > sizes-gimplified public unsigned restrict SI size <integer_cst 0xf7f0f9d8 32> unit size <integer_cst 0xf7f0f7c4 4> > align 32 symtab 0 alias set -1 canonical type 0xf7fa6870> > > arg 0 <plus_expr 0xf7fc95e8 type <integer_type 0xf7f12438 long unsigned int> > arg 0 <var_decl 0xf7fc4a6c D.1768> > arg 1 <integer_cst 0xf7fb7bec constant 4> > tst.c:7:5> > tst.c:7:5> > tst.c:7:5> > > Is the RTL expansion wrong or the orginal tree node is constructed incorrectly? > > Thanks, > Bingfeng Mei > > Broadcom UK > [-- Attachment #2: p --] [-- Type: application/octet-stream, Size: 2030 bytes --] Index: gcc/alias.c =================================================================== *** gcc/alias.c (revision 148119) --- gcc/alias.c (working copy) *************** get_deref_alias_set_1 (tree t) *** 536,547 **** { tree decl = find_base_decl (t); ! if (decl && DECL_POINTER_ALIAS_SET_KNOWN_P (decl)) { /* If we haven't computed the actual alias set, do it now. */ ! if (DECL_POINTER_ALIAS_SET (decl) == -2) { ! tree pointed_to_type = TREE_TYPE (TREE_TYPE (decl)); /* No two restricted pointers can point at the same thing. However, a restricted pointer can point at the same thing --- 536,550 ---- { tree decl = find_base_decl (t); ! if (decl ! && POINTER_TYPE_P (TREE_TYPE (decl)) ! && TYPE_RESTRICT (TREE_TYPE (decl))) { /* If we haven't computed the actual alias set, do it now. */ ! if (DECL_POINTER_ALIAS_SET (decl) == -2 ! || !DECL_POINTER_ALIAS_SET_KNOWN_P (decl)) { ! tree pointed_to_type = TREE_TYPE (TREE_TYPE (t)); /* No two restricted pointers can point at the same thing. However, a restricted pointer can point at the same thing *************** get_deref_alias_set_1 (tree t) *** 556,562 **** if (pointed_to_alias_set == 0) /* It's not legal to make a subset of alias set zero. */ DECL_POINTER_ALIAS_SET (decl) = 0; ! else if (AGGREGATE_TYPE_P (pointed_to_type)) /* For an aggregate, we must treat the restricted pointer the same as an ordinary pointer. If we were to make the type pointed to by the --- 559,566 ---- if (pointed_to_alias_set == 0) /* It's not legal to make a subset of alias set zero. */ DECL_POINTER_ALIAS_SET (decl) = 0; ! else if (AGGREGATE_TYPE_P (pointed_to_type) ! && TREE_CODE (pointed_to_type) != ARRAY_TYPE) /* For an aggregate, we must treat the restricted pointer the same as an ordinary pointer. If we were to make the type pointed to by the ^ permalink raw reply [flat|nested] 6+ messages in thread
* RE: Restrict keyword doesn't work correctly in GCC 4.4 2009-06-03 10:53 ` Richard Guenther @ 2009-06-03 11:02 ` Bingfeng Mei 2009-06-03 14:09 ` Richard Guenther 0 siblings, 1 reply; 6+ messages in thread From: Bingfeng Mei @ 2009-06-03 11:02 UTC (permalink / raw) To: Richard Guenther; +Cc: gcc Richard, Yes, my original code does have restrict qualified decl: void foo(int byte, char *a, char *b){ int * restrict dest = (int *)a; int * restrict src = (int *)b; for(int i = 0; i < byte/8; i++){ *dest++ = *src++; } } The code I shown is produced by tree level compilation. *(int * restrict) (D.1934 + 4) = *(int * restrict) (D.1936 + 4); *(int * restrict) (D.1934 + 8) = *(int * restrict) (D.1936 + 8); *(int * restrict) (D.1934 + 12) = *(int * restrict) (D.1936 + 12); *(int * restrict) (D.1934 + 16) = *(int * restrict) (D.1936 + 16); *(int * restrict) (D.1934 + 20) = *(int * restrict) (D.1936 + 20); *(int * restrict) (D.1934 + 24) = *(int * restrict) (D.1936 + 24); *(int * restrict) (D.1934 + 28) = *(int * restrict) (D.1936 + 28); *(int * restrict) (D.1934 + 32) = *(int * restrict) (D.1936 + 32); *(int * restrict) (D.1934 + 36) = *(int * restrict) (D.1936 + 36); *(int * restrict) (D.1934 + 40) = *(int * restrict) (D.1936 + 40); *(int * restrict) (D.1934 + 44) = *(int * restrict) (D.1936 + 44); *(int * restrict) (D.1934 + 48) = *(int * restrict) (D.1936 + 48); *(int * restrict) (D.1934 + 52) = *(int * restrict) (D.1936 + 52); *(int * restrict) (D.1934 + 56) = *(int * restrict) (D.1936 + 56); *(int * restrict) (D.1934 + 60) = *(int * restrict) (D.1936 + 60); If we agree these tree statements still preserve the meaning of restrict, it should be RTL expansion going wrong. Am I right? - Bingfeng > -----Original Message----- > From: Richard Guenther [mailto:richard.guenther@gmail.com] > Sent: 03 June 2009 11:54 > To: Bingfeng Mei > Cc: gcc@gcc.gnu.org > Subject: Re: Restrict keyword doesn't work correctly in GCC 4.4 > > On Wed, Jun 3, 2009 at 12:41 PM, Bingfeng Mei > <bmei@broadcom.com> wrote: > > Hello, > > I noticed that the restrict doesn't work fully on 4.4.0 > (used to work on > > our port based on 4.3 branch). The problem is that tree > optimizer can do a > > lot of optimization regarding pointer, e.g., at -O3. The > alias set property > > is not propagated accordingly. > > > > Is the following RTL expansion correct? Both read and write > address are > > converted to a restrict pointer, but the both mem rtx have > the same alias set (2). > > > > ;; *(int * restrict) (D.1768 + 4) = *(int * restrict) (D.1770 + 4); > > restrict only works if there is a restrict qualified pointer decl in > your source. > > I will re-implement restrict support completely for 4.5. > > You can try the attached hack which might help (but also cause > weird effects ...). > > Richard. > > > (insn 56 55 57 tst.c:7 (set (reg:SI 124) > > (mem:SI (plus:SI (reg:SI 103 [ D.1770 ]) > > (const_int 4 [0x4])) [2 S4 A32])) -1 (nil)) > > > > (insn 57 56 0 tst.c:7 (set (mem:SI (plus:SI (reg:SI 104 [ D.1768 ]) > > (const_int 4 [0x4])) [2 S4 A32]) > > (reg:SI 124)) -1 (nil)) > > > > > > The alias set property is copied from tree node: > > <indirect_ref 0xf7f09d40 > > type <integer_type 0xf7f122f4 int sizes-gimplified public SI > > size <integer_cst 0xf7f0f9d8 constant 32> > > unit size <integer_cst 0xf7f0f7c4 constant 4> > > align 32 symtab 0 alias set 2 canonical type > 0xf7f122f4 precision 32 min <integer_cst 0xf7f0f984 > -2147483648> max <integer_cst 0xf7f0f9a0 2147483647> > > pointer_to_this <pointer_type 0xf7f18798>> > > > > arg 0 <nop_expr 0xf7fc7400 > > type <pointer_type 0xf7fa6870 type <integer_type > 0xf7f122f4 int> > > sizes-gimplified public unsigned restrict SI > size <integer_cst 0xf7f0f9d8 32> unit size <integer_cst 0xf7f0f7c4 4> > > align 32 symtab 0 alias set -1 canonical type 0xf7fa6870> > > > > arg 0 <plus_expr 0xf7fc95e8 type <integer_type > 0xf7f12438 long unsigned int> > > arg 0 <var_decl 0xf7fc4a6c D.1768> > > arg 1 <integer_cst 0xf7fb7bec constant 4> > > tst.c:7:5> > > tst.c:7:5> > > tst.c:7:5> > > > > Is the RTL expansion wrong or the orginal tree node is > constructed incorrectly? > > > > Thanks, > > Bingfeng Mei > > > > Broadcom UK > > > ^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: Restrict keyword doesn't work correctly in GCC 4.4 2009-06-03 11:02 ` Bingfeng Mei @ 2009-06-03 14:09 ` Richard Guenther 2009-06-03 15:35 ` Bingfeng Mei 0 siblings, 1 reply; 6+ messages in thread From: Richard Guenther @ 2009-06-03 14:09 UTC (permalink / raw) To: Bingfeng Mei; +Cc: gcc On Wed, Jun 3, 2009 at 1:02 PM, Bingfeng Mei <bmei@broadcom.com> wrote: > Richard, > Yes, my original code does have restrict qualified decl: > > void foo(int byte, char *a, char *b){ > int * restrict dest = (int *)a; > int * restrict src = (int *)b; > > for(int i = 0; i < byte/8; i++){ > *dest++ = *src++; > } > } > > > The code I shown is produced by tree level compilation. > > *(int * restrict) (D.1934 + 4) = *(int * restrict) (D.1936 + 4); > *(int * restrict) (D.1934 + 8) = *(int * restrict) (D.1936 + 8); > *(int * restrict) (D.1934 + 12) = *(int * restrict) (D.1936 + 12); > *(int * restrict) (D.1934 + 16) = *(int * restrict) (D.1936 + 16); > *(int * restrict) (D.1934 + 20) = *(int * restrict) (D.1936 + 20); > *(int * restrict) (D.1934 + 24) = *(int * restrict) (D.1936 + 24); > *(int * restrict) (D.1934 + 28) = *(int * restrict) (D.1936 + 28); > *(int * restrict) (D.1934 + 32) = *(int * restrict) (D.1936 + 32); > *(int * restrict) (D.1934 + 36) = *(int * restrict) (D.1936 + 36); > *(int * restrict) (D.1934 + 40) = *(int * restrict) (D.1936 + 40); > *(int * restrict) (D.1934 + 44) = *(int * restrict) (D.1936 + 44); > *(int * restrict) (D.1934 + 48) = *(int * restrict) (D.1936 + 48); > *(int * restrict) (D.1934 + 52) = *(int * restrict) (D.1936 + 52); > *(int * restrict) (D.1934 + 56) = *(int * restrict) (D.1936 + 56); > *(int * restrict) (D.1934 + 60) = *(int * restrict) (D.1936 + 60); > > If we agree these tree statements still preserve the meaning of restrict, > it should be RTL expansion going wrong. Am I right? No, it is TER that removes the temporary that is required to make restrict work. Try -fno-tree-ter or fixing TER to not TER to-restrict-pointer conversions. Richard. > > - Bingfeng > > >> -----Original Message----- >> From: Richard Guenther [mailto:richard.guenther@gmail.com] >> Sent: 03 June 2009 11:54 >> To: Bingfeng Mei >> Cc: gcc@gcc.gnu.org >> Subject: Re: Restrict keyword doesn't work correctly in GCC 4.4 >> >> On Wed, Jun 3, 2009 at 12:41 PM, Bingfeng Mei >> <bmei@broadcom.com> wrote: >> > Hello, >> > I noticed that the restrict doesn't work fully on 4.4.0 >> (used to work on >> > our port based on 4.3 branch). The problem is that tree >> optimizer can do a >> > lot of optimization regarding pointer, e.g., at -O3. The >> alias set property >> > is not propagated accordingly. >> > >> > Is the following RTL expansion correct? Both read and write >> address are >> > converted to a restrict pointer, but the both mem rtx have >> the same alias set (2). >> > >> > ;; *(int * restrict) (D.1768 + 4) = *(int * restrict) (D.1770 + 4); >> >> restrict only works if there is a restrict qualified pointer decl in >> your source. >> >> I will re-implement restrict support completely for 4.5. >> >> You can try the attached hack which might help (but also cause >> weird effects ...). >> >> Richard. >> >> > (insn 56 55 57 tst.c:7 (set (reg:SI 124) >> > (mem:SI (plus:SI (reg:SI 103 [ D.1770 ]) >> > (const_int 4 [0x4])) [2 S4 A32])) -1 (nil)) >> > >> > (insn 57 56 0 tst.c:7 (set (mem:SI (plus:SI (reg:SI 104 [ D.1768 ]) >> > (const_int 4 [0x4])) [2 S4 A32]) >> > (reg:SI 124)) -1 (nil)) >> > >> > >> > The alias set property is copied from tree node: >> > <indirect_ref 0xf7f09d40 >> > type <integer_type 0xf7f122f4 int sizes-gimplified public SI >> > size <integer_cst 0xf7f0f9d8 constant 32> >> > unit size <integer_cst 0xf7f0f7c4 constant 4> >> > align 32 symtab 0 alias set 2 canonical type >> 0xf7f122f4 precision 32 min <integer_cst 0xf7f0f984 >> -2147483648> max <integer_cst 0xf7f0f9a0 2147483647> >> > pointer_to_this <pointer_type 0xf7f18798>> >> > >> > arg 0 <nop_expr 0xf7fc7400 >> > type <pointer_type 0xf7fa6870 type <integer_type >> 0xf7f122f4 int> >> > sizes-gimplified public unsigned restrict SI >> size <integer_cst 0xf7f0f9d8 32> unit size <integer_cst 0xf7f0f7c4 4> >> > align 32 symtab 0 alias set -1 canonical type 0xf7fa6870> >> > >> > arg 0 <plus_expr 0xf7fc95e8 type <integer_type >> 0xf7f12438 long unsigned int> >> > arg 0 <var_decl 0xf7fc4a6c D.1768> >> > arg 1 <integer_cst 0xf7fb7bec constant 4> >> > tst.c:7:5> >> > tst.c:7:5> >> > tst.c:7:5> >> > >> > Is the RTL expansion wrong or the orginal tree node is >> constructed incorrectly? >> > >> > Thanks, >> > Bingfeng Mei >> > >> > Broadcom UK >> > >> > ^ permalink raw reply [flat|nested] 6+ messages in thread
* RE: Restrict keyword doesn't work correctly in GCC 4.4 2009-06-03 14:09 ` Richard Guenther @ 2009-06-03 15:35 ` Bingfeng Mei 2009-06-03 15:46 ` Richard Guenther 0 siblings, 1 reply; 6+ messages in thread From: Bingfeng Mei @ 2009-06-03 15:35 UTC (permalink / raw) To: Richard Guenther; +Cc: gcc Richard, Thanks. I tried your patch and the -fno-tree-ter, and none works. The problem is that decl = find_base_decl (TREE_OPERAND (inner, 0)); <--- Cannot find the base declaration, so decl = 0 if (decl <-- won't be checked && POINTER_TYPE_P (TREE_TYPE (decl)) && TYPE_RESTRICT (TREE_TYPE (decl))) The TREE_OPERAND (inner, 0) is: <nop_expr 0xf7fc7400 type <pointer_type 0xf7fa6870 type <integer_type 0xf7f122f4 int sizes-gimplified public SI size <integer_cst 0xf7f0f9d8 constant 32> unit size <integer_cst 0xf7f0f7c4 constant 4> align 32 symtab 0 alias set 2 canonical type 0xf7f122f4 precision 32 min <integer_cst 0xf7f0f984 -2147483648> max <integer_cst 0xf7f0f9a0 2147483647> pointer_to_this <pointer_type 0xf7f18798>> sizes-gimplified public unsigned restrict SI size <integer_cst 0xf7f0f9d8 32> unit size <integer_cst 0xf7f0f7c4 4> align 32 symtab 0 alias set -1 canonical type 0xf7fa6870> arg 0 <plus_expr 0xf7fc95e8 type <integer_type 0xf7f12438 long unsigned int public unsigned SI size <integer_cst 0xf7f0f9d8 32> unit size <integer_cst 0xf7f0f7c4 4> align 32 symtab 0 alias set -1 canonical type 0xf7f12438 precision 32 min <integer_cst 0xf7f0fa64 0> max <integer_cst 0xf7f0fa48 4294967295>> arg 0 <var_decl 0xf7fc4a6c D.1768 type <integer_type 0xf7f12438 long unsigned int> used unsigned ignored SI file tst.c line 1 col 6 size <integer_cst 0xf7f0f9d8 32> unit size <integer_cst 0xf7f0f7c4 4> align 32 context <function_decl 0xf7fa7080 foo> (reg:SI 104 [ D.1768 ])> arg 1 <integer_cst 0xf7fb7bec constant 4> tst.c:7:5> tst.c:7:5> I added the following code. It seems to work for my example and others. Not sure potential hazard with it. ... else if(!decl && POINTER_TYPE_P (TREE_TYPE (TREE_OPERAND(inner, 0))) && TYPE_RESTRICT (TREE_TYPE (TREE_OPERAND(inner, 0)))) { return new_alias_set (); } .... Bingfeng > -----Original Message----- > From: Richard Guenther [mailto:richard.guenther@gmail.com] > Sent: 03 June 2009 15:10 > To: Bingfeng Mei > Cc: gcc@gcc.gnu.org > Subject: Re: Restrict keyword doesn't work correctly in GCC 4.4 > > On Wed, Jun 3, 2009 at 1:02 PM, Bingfeng Mei > <bmei@broadcom.com> wrote: > > Richard, > > Yes, my original code does have restrict qualified decl: > > > > void foo(int byte, char *a, char *b){ > > int * restrict dest = (int *)a; > > int * restrict src = (int *)b; > > > > for(int i = 0; i < byte/8; i++){ > > *dest++ = *src++; > > } > > } > > > > > > The code I shown is produced by tree level compilation. > > > > *(int * restrict) (D.1934 + 4) = *(int * restrict) (D.1936 + 4); > > *(int * restrict) (D.1934 + 8) = *(int * restrict) (D.1936 + 8); > > *(int * restrict) (D.1934 + 12) = *(int * restrict) (D.1936 + 12); > > *(int * restrict) (D.1934 + 16) = *(int * restrict) (D.1936 + 16); > > *(int * restrict) (D.1934 + 20) = *(int * restrict) (D.1936 + 20); > > *(int * restrict) (D.1934 + 24) = *(int * restrict) (D.1936 + 24); > > *(int * restrict) (D.1934 + 28) = *(int * restrict) (D.1936 + 28); > > *(int * restrict) (D.1934 + 32) = *(int * restrict) (D.1936 + 32); > > *(int * restrict) (D.1934 + 36) = *(int * restrict) (D.1936 + 36); > > *(int * restrict) (D.1934 + 40) = *(int * restrict) (D.1936 + 40); > > *(int * restrict) (D.1934 + 44) = *(int * restrict) (D.1936 + 44); > > *(int * restrict) (D.1934 + 48) = *(int * restrict) (D.1936 + 48); > > *(int * restrict) (D.1934 + 52) = *(int * restrict) (D.1936 + 52); > > *(int * restrict) (D.1934 + 56) = *(int * restrict) (D.1936 + 56); > > *(int * restrict) (D.1934 + 60) = *(int * restrict) (D.1936 + 60); > > > > If we agree these tree statements still preserve the > meaning of restrict, > > it should be RTL expansion going wrong. Am I right? > > No, it is TER that removes the temporary that is required to make > restrict work. Try -fno-tree-ter or fixing TER to not TER > to-restrict-pointer conversions. > > Richard. > > > > > - Bingfeng > > > > > >> -----Original Message----- > >> From: Richard Guenther [mailto:richard.guenther@gmail.com] > >> Sent: 03 June 2009 11:54 > >> To: Bingfeng Mei > >> Cc: gcc@gcc.gnu.org > >> Subject: Re: Restrict keyword doesn't work correctly in GCC 4.4 > >> > >> On Wed, Jun 3, 2009 at 12:41 PM, Bingfeng Mei > >> <bmei@broadcom.com> wrote: > >> > Hello, > >> > I noticed that the restrict doesn't work fully on 4.4.0 > >> (used to work on > >> > our port based on 4.3 branch). The problem is that tree > >> optimizer can do a > >> > lot of optimization regarding pointer, e.g., at -O3. The > >> alias set property > >> > is not propagated accordingly. > >> > > >> > Is the following RTL expansion correct? Both read and write > >> address are > >> > converted to a restrict pointer, but the both mem rtx have > >> the same alias set (2). > >> > > >> > ;; *(int * restrict) (D.1768 + 4) = *(int * restrict) > (D.1770 + 4); > >> > >> restrict only works if there is a restrict qualified > pointer decl in > >> your source. > >> > >> I will re-implement restrict support completely for 4.5. > >> > >> You can try the attached hack which might help (but also cause > >> weird effects ...). > >> > >> Richard. > >> > >> > (insn 56 55 57 tst.c:7 (set (reg:SI 124) > >> > (mem:SI (plus:SI (reg:SI 103 [ D.1770 ]) > >> > (const_int 4 [0x4])) [2 S4 A32])) -1 (nil)) > >> > > >> > (insn 57 56 0 tst.c:7 (set (mem:SI (plus:SI (reg:SI 104 > [ D.1768 ]) > >> > (const_int 4 [0x4])) [2 S4 A32]) > >> > (reg:SI 124)) -1 (nil)) > >> > > >> > > >> > The alias set property is copied from tree node: > >> > <indirect_ref 0xf7f09d40 > >> > type <integer_type 0xf7f122f4 int sizes-gimplified public SI > >> > size <integer_cst 0xf7f0f9d8 constant 32> > >> > unit size <integer_cst 0xf7f0f7c4 constant 4> > >> > align 32 symtab 0 alias set 2 canonical type > >> 0xf7f122f4 precision 32 min <integer_cst 0xf7f0f984 > >> -2147483648> max <integer_cst 0xf7f0f9a0 2147483647> > >> > pointer_to_this <pointer_type 0xf7f18798>> > >> > > >> > arg 0 <nop_expr 0xf7fc7400 > >> > type <pointer_type 0xf7fa6870 type <integer_type > >> 0xf7f122f4 int> > >> > sizes-gimplified public unsigned restrict SI > >> size <integer_cst 0xf7f0f9d8 32> unit size <integer_cst > 0xf7f0f7c4 4> > >> > align 32 symtab 0 alias set -1 canonical type > 0xf7fa6870> > >> > > >> > arg 0 <plus_expr 0xf7fc95e8 type <integer_type > >> 0xf7f12438 long unsigned int> > >> > arg 0 <var_decl 0xf7fc4a6c D.1768> > >> > arg 1 <integer_cst 0xf7fb7bec constant 4> > >> > tst.c:7:5> > >> > tst.c:7:5> > >> > tst.c:7:5> > >> > > >> > Is the RTL expansion wrong or the orginal tree node is > >> constructed incorrectly? > >> > > >> > Thanks, > >> > Bingfeng Mei > >> > > >> > Broadcom UK > >> > > >> > > > > ^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: Restrict keyword doesn't work correctly in GCC 4.4 2009-06-03 15:35 ` Bingfeng Mei @ 2009-06-03 15:46 ` Richard Guenther 0 siblings, 0 replies; 6+ messages in thread From: Richard Guenther @ 2009-06-03 15:46 UTC (permalink / raw) To: Bingfeng Mei; +Cc: gcc On Wed, Jun 3, 2009 at 5:34 PM, Bingfeng Mei <bmei@broadcom.com> wrote: > Richard, > Thanks. I tried your patch and the -fno-tree-ter, and none works. The problem is that > > decl = find_base_decl (TREE_OPERAND (inner, 0)); <--- Cannot find the base declaration, so decl = 0 > > if (decl <-- won't be checked > && POINTER_TYPE_P (TREE_TYPE (decl)) > && TYPE_RESTRICT (TREE_TYPE (decl))) > > > The TREE_OPERAND (inner, 0) is: > > <nop_expr 0xf7fc7400 > type <pointer_type 0xf7fa6870 > type <integer_type 0xf7f122f4 int sizes-gimplified public SI > size <integer_cst 0xf7f0f9d8 constant 32> > unit size <integer_cst 0xf7f0f7c4 constant 4> > align 32 symtab 0 alias set 2 canonical type 0xf7f122f4 precision 32 min <integer_cst 0xf7f0f984 -2147483648> max <integer_cst 0xf7f0f9a0 2147483647> > pointer_to_this <pointer_type 0xf7f18798>> > sizes-gimplified public unsigned restrict SI size <integer_cst 0xf7f0f9d8 32> unit size <integer_cst 0xf7f0f7c4 4> > align 32 symtab 0 alias set -1 canonical type 0xf7fa6870> > > arg 0 <plus_expr 0xf7fc95e8 > type <integer_type 0xf7f12438 long unsigned int public unsigned SI size <integer_cst 0xf7f0f9d8 32> unit size <integer_cst 0xf7f0f7c4 4> > align 32 symtab 0 alias set -1 canonical type 0xf7f12438 precision 32 min <integer_cst 0xf7f0fa64 0> max <integer_cst 0xf7f0fa48 4294967295>> > > arg 0 <var_decl 0xf7fc4a6c D.1768 type <integer_type 0xf7f12438 long unsigned int> > used unsigned ignored SI file tst.c line 1 col 6 size <integer_cst 0xf7f0f9d8 32> unit size <integer_cst 0xf7f0f7c4 4> > align 32 context <function_decl 0xf7fa7080 foo> > (reg:SI 104 [ D.1768 ])> > arg 1 <integer_cst 0xf7fb7bec constant 4> > tst.c:7:5> > tst.c:7:5> > > > I added the following code. It seems to work for my example and others. Not sure potential hazard with it. > ... > else if(!decl > && POINTER_TYPE_P (TREE_TYPE (TREE_OPERAND(inner, 0))) > && TYPE_RESTRICT (TREE_TYPE (TREE_OPERAND(inner, 0)))) > { > return new_alias_set (); > } > .... > Ah, of course. As I said - restrict support is broken. Richard. ^ permalink raw reply [flat|nested] 6+ messages in thread
end of thread, other threads:[~2009-06-03 15:46 UTC | newest] Thread overview: 6+ messages (download: mbox.gz / follow: Atom feed) -- links below jump to the message on this page -- 2009-06-03 10:42 Restrict keyword doesn't work correctly in GCC 4.4 Bingfeng Mei 2009-06-03 10:53 ` Richard Guenther 2009-06-03 11:02 ` Bingfeng Mei 2009-06-03 14:09 ` Richard Guenther 2009-06-03 15:35 ` Bingfeng Mei 2009-06-03 15:46 ` Richard Guenther
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