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Re: IVOPT improvement patch
Ok, if you insist on the perfection :)
David
On Tue, Aug 10, 2010 at 10:13 AM, H.J. Lu <hjl.tools@gmail.com> wrote:
> On Tue, Aug 10, 2010 at 10:09 AM, Xinliang David Li <davidxl@google.com> wrote:
>> see attached.
>>
>> David
>>
>
> You have
>
> + ? ? ?data->max_offset = (i == -1? 0 : off);
> + ? ? ?off = data->max_offset;
>
> if (i == -1)
> ?off = 0;
> data->max_offset; = off;
>
> may ?avoid one memory access.
>
> --
> H.J.
>
Index: tree-ssa-loop-ivopts.c
===================================================================
--- tree-ssa-loop-ivopts.c (revision 162822)
+++ tree-ssa-loop-ivopts.c (working copy)
@@ -3241,9 +3241,8 @@ get_address_cost (bool symbol_present, b
if (!data)
{
HOST_WIDE_INT i;
- HOST_WIDE_INT start = BIGGEST_ALIGNMENT / BITS_PER_UNIT;
- HOST_WIDE_INT rat, off;
- int old_cse_not_expected;
+ HOST_WIDE_INT rat, off = 0;
+ int old_cse_not_expected, width;
unsigned sym_p, var_p, off_p, rat_p, add_c;
rtx seq, addr, base;
rtx reg0, reg1;
@@ -3252,33 +3251,40 @@ get_address_cost (bool symbol_present, b
reg1 = gen_raw_REG (address_mode, LAST_VIRTUAL_REGISTER + 1);
+ width = GET_MODE_BITSIZE (address_mode) - 1;
+ if (width > (HOST_BITS_PER_WIDE_INT - 1))
+ width = HOST_BITS_PER_WIDE_INT - 1;
addr = gen_rtx_fmt_ee (PLUS, address_mode, reg1, NULL_RTX);
- for (i = start; i <= 1 << 20; i <<= 1)
+
+ for (i = width; i >= 0; i--)
{
- XEXP (addr, 1) = gen_int_mode (i, address_mode);
- if (!memory_address_addr_space_p (mem_mode, addr, as))
+ off = -((HOST_WIDE_INT) 1 << i);
+ XEXP (addr, 1) = gen_int_mode (off, address_mode);
+ if (memory_address_addr_space_p (mem_mode, addr, as))
break;
}
- data->max_offset = i == start ? 0 : i >> 1;
- off = data->max_offset;
+ data->min_offset = (i == -1? 0 : off);
- for (i = start; i <= 1 << 20; i <<= 1)
+ for (i = width; i >= 0; i--)
{
- XEXP (addr, 1) = gen_int_mode (-i, address_mode);
- if (!memory_address_addr_space_p (mem_mode, addr, as))
+ off = ((HOST_WIDE_INT) 1 << i) - 1;
+ XEXP (addr, 1) = gen_int_mode (off, address_mode);
+ if (memory_address_addr_space_p (mem_mode, addr, as))
break;
}
- data->min_offset = i == start ? 0 : -(i >> 1);
+ if (i == -1)
+ off = 0;
+ data->max_offset = off;
if (dump_file && (dump_flags & TDF_DETAILS))
{
fprintf (dump_file, "get_address_cost:\n");
- fprintf (dump_file, " min offset %s %d\n",
+ fprintf (dump_file, " min offset %s " HOST_WIDE_INT_PRINT_DEC "\n",
GET_MODE_NAME (mem_mode),
- (int) data->min_offset);
- fprintf (dump_file, " max offset %s %d\n",
+ data->min_offset);
+ fprintf (dump_file, " max offset %s " HOST_WIDE_INT_PRINT_DEC "\n",
GET_MODE_NAME (mem_mode),
- (int) data->max_offset);
+ data->max_offset);
}
rat = 1;