>Среда, 12 июня 2019, 1:54 +05:00 от Jim Wilson <jimw@xxxxxxxxxx>: > >On Tue, Jun 11, 2019 at 1:32 AM Alex Hill < hardest2005@xxxxxxx > wrote: >> BUT! In case we using IF loop GCC wont emit minmax AGAIN! >It looks like the memory accesses are the problem, not the control >flow. However, the control flow may be affecting exactly how the >compiler optimizes the memory references. If you create a temporary >variable, store the result in the temporary variable, and then write >the temporary variable to memory at the end, it should be optimized >regardless of control flow. > >> what`s the difference between >> (reg:DI 113 [ ivtmp.29 ]) [1 MEM[base: _39, offset: 0B]+0 S8 A64]) >> and >> (reg/f:DI 89 [ _48 ]) [1 *_48+0 S8 A64]) > >_ivtmp.29 and _48 are variable names. In both cases, these are >variable names created by high level optimization passes. See the >-fdump-tree-all output, and look at the last one before the conversion >to RTL. > >The MEM is giving alias analysis info. A is the alignment, S is the >size. The first number is the alias set, where alias set 0 aliases >everything, and other numbers only alias values in the same alias set. >The MEM is the original base and offset for this address, where _39 is >again a compiler generated variable. You can find the code that >prints this stuff in print-rtl.c, and then you probably need to look >at the alias analysis code if you want to know more. > >See also the noce_try_minmax function I pointed at earlier, to see why >it works in one case but not in another case. > >Jim I`m still looking for the way to emit minmax, now i`m try to find solution in ifcvt.c, is there exist a way to dump conditional execution step by step, i`m interesting in functions: df_analyze in df-core.c noce_process_if_block in ifcvt.c noce_try_minmax in ifcvt.c I read more than thousand pages from documents from gnu.gcc.org, try to find in internet but i can`t find how to dump every step of rtl passes, for example 243.r.ce1, there is only general info in dumps receivced by fdump-rtl-all. In 243.r.ce1 just told "df_analyze called" and nothing else. Sorry for my Engrish Kind regards Alex Hill.
