| Message ID | mpt5ywmbtav.fsf@arm.com |
|---|---|
| State | New |
| Headers | show |
| Series | vect: Tweak dump messages for vector mode choice | expand |
On Tue, Aug 3, 2021 at 2:35 PM Richard Sandiford via Gcc-patches <gcc-patches@gcc.gnu.org> wrote: > > After vect_analyze_loop has successfully analysed a loop for > one base vector mode B1, it considers using following base vector > modes to vectorise an epilogue. However, for VECT_COMPARE_COSTS, > a later mode B2 might turn out to be better than B1 was. Initially > this comparison will be between an epilogue loop (for B2) and a main > loop (for B1). However, in r11-6458 I'd added code to reanalyse the > B2 epilogue loop as a main loop, partly for correctness and partly > for better costing. > > This can lead to a situation in which we think that the B2 epilogue > loop was better than the B1 main loop, but that the B2 main loop is > not better than the B1 main loop. There was no dump message to say > that this had happened, which made it look like B2 had still won. > > Tested on aarch64-linux-gnu and x86_64-linux-gnu. OK to install? OK. > Richard > > > gcc/ > * tree-vect-loop.c (vect_analyze_loop): Print a dump message > when a reanalyzed loop fails to be cheaper than the current > main loop. > --- > gcc/tree-vect-loop.c | 11 ++++++++++- > 1 file changed, 10 insertions(+), 1 deletion(-) > > diff --git a/gcc/tree-vect-loop.c b/gcc/tree-vect-loop.c > index 00a57b2ba62..48a54b0957f 100644 > --- a/gcc/tree-vect-loop.c > +++ b/gcc/tree-vect-loop.c > @@ -3064,7 +3064,16 @@ vect_analyze_loop (class loop *loop, vec_info_shared *shared) > = opt_loop_vec_info::success (main_loop_vinfo); > } > else > - delete main_loop_vinfo; > + { > + if (dump_enabled_p ()) > + dump_printf_loc (MSG_NOTE, vect_location, > + "***** No longer preferring vector" > + " mode %s after reanalyzing the loop" > + " as a main loop\n", > + GET_MODE_NAME > + (main_loop_vinfo->vector_mode)); > + delete main_loop_vinfo; > + } > } > } > > -- > 2.17.1 >
diff --git a/gcc/tree-vect-loop.c b/gcc/tree-vect-loop.c index 00a57b2ba62..48a54b0957f 100644 --- a/gcc/tree-vect-loop.c +++ b/gcc/tree-vect-loop.c @@ -3064,7 +3064,16 @@ vect_analyze_loop (class loop *loop, vec_info_shared *shared) = opt_loop_vec_info::success (main_loop_vinfo); } else - delete main_loop_vinfo; + { + if (dump_enabled_p ()) + dump_printf_loc (MSG_NOTE, vect_location, + "***** No longer preferring vector" + " mode %s after reanalyzing the loop" + " as a main loop\n", + GET_MODE_NAME + (main_loop_vinfo->vector_mode)); + delete main_loop_vinfo; + } } }