On Thu, May 16, 2013 at 1:35 PM, Bin.Cheng <amker.ch...@gmail.com> wrote: > On Thu, May 16, 2013 at 7:21 PM, Bin.Cheng <amker.ch...@gmail.com> wrote: >> On Sun, Apr 28, 2013 at 8:15 PM, Richard Biener >> <richard.guent...@gmail.com> wrote: >>> "Bin.Cheng" <amker.ch...@gmail.com> wrote: >>> >>>>I suspect codes in prepare_decl_rtl: >>>> >>>> case VAR_DECL: >>>> case PARM_DECL: >>>> case RESULT_DECL: >>>> *ws = 0; >>>> obj = *expr_p; >>>> >>>> if (DECL_RTL_SET_P (obj)) >>>> break; >>>> >>>> if (DECL_MODE (obj) == BLKmode) >>>> x = produce_memory_decl_rtl (obj, regno); >>>> else >>>> x = gen_raw_REG (DECL_MODE (obj), (*regno)++); >>>> >>>>It generates RTX_REG(regno) for an var_decl which is an array has >>>>DECL_MODE == OImode. >>>> >>>>Any suggestions? >>> >>> Addr_expr cost should be computed by >>> Looking at the cost for the address computation. Not by simply expanding >>> the address_expr. Look at get_inner_reference and handle the returned base >>> specially. >>> >> Sorry for missing the message and late reply. >> >> I think the addr_expr should be expanded in some cases, for example, >> computing the base cost of iv candidate. >> Considering below candidate: >> >> candidate 22 >> var_before ivtmp.27 >> var_after ivtmp.27 >> incremented before use 1 >> type unsigned int >> base (unsigned int) ((long unsigned int *) &GasmanStatAlive + 4294967292) >> step 4 >> base object (void *) &GasmanStatAlive >> Candidate 22 is related to use 1 >> candidate 23 >> var_before ivtmp.28 >> var_after ivtmp.28 >> incremented after use 1 >> type unsigned int >> base (unsigned int) &GasmanStatAlive >> step 4 >> base object (void *) &GasmanStatAlive >> Candidate 23 is related to use 1 >> >> the cost of computing base_22 in loop preheader is more expensive than >> base_23. It's not computed as an address, so expanding would be >> necessary. > A mistake, the base expressions are in form: > &array[0][offset] > &array[0][0]
Yes, computing &array[0][offset] may be more expensive than computing &array[0][0]. Richard. >> >> Is it true, or something missed? >> >> Thanks again. >> >> >> --- Best Regards. > > > > -- > Best Regards.
