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.guent...@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
> <b...@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
> >
>
