From af8955112f4d3294d9cc50a2a125718b202321f0 Mon Sep 17 00:00:00 2001 From: Robin Dapp Date: Thu, 3 Mar 2022 15:06:21 +0100 Subject: s390: Add -munroll-only-small-loops. Inspired by Power we also introduce -munroll-only-small-loops. This implies activating -funroll-loops and -munroll-only-small-loops at -O2 and above. gcc/ChangeLog: * common/config/s390/s390-common.cc: Enable -funroll-loops and -munroll-only-small-loops for OPT_LEVELS_2_PLUS_SPEED_ONLY. * config/s390/s390.cc (s390_loop_unroll_adjust): Do not unroll loops larger than 12 instructions. (s390_override_options_after_change): Set unroll options. (s390_option_override_internal): Likewise. * config/s390/s390.opt: Document munroll-only-small-loops. gcc/testsuite/ChangeLog: * gcc.target/s390/vector/vec-copysign.c: Do not unroll. * gcc.target/s390/zvector/autovec-double-quiet-uneq.c: Dito. * gcc.target/s390/zvector/autovec-double-signaling-ltgt.c: Dito. * gcc.target/s390/zvector/autovec-float-quiet-uneq.c: Dito. * gcc.target/s390/zvector/autovec-float-signaling-ltgt.c: Dito. --- gcc/config/s390/s390.cc | 31 +++++++++++++++++++++++++++++++ gcc/config/s390/s390.opt | 4 ++++ 2 files changed, 35 insertions(+) (limited to 'gcc/config/s390') diff --git a/gcc/config/s390/s390.cc b/gcc/config/s390/s390.cc index 5e06bf9..942ed26 100644 --- a/gcc/config/s390/s390.cc +++ b/gcc/config/s390/s390.cc @@ -15420,6 +15420,21 @@ s390_loop_unroll_adjust (unsigned nunroll, struct loop *loop) if (s390_tune < PROCESSOR_2097_Z10) return nunroll; + if (unroll_only_small_loops) + { + /* Only unroll loops smaller than or equal to 12 insns. */ + const unsigned int small_threshold = 12; + + if (loop->ninsns > small_threshold) + return 0; + + /* ???: Make this dependent on the type of registers in + the loop. Increase the limit for vector registers. */ + const unsigned int max_insns = optimize >= 3 ? 36 : 24; + + nunroll = MIN (nunroll, max_insns / loop->ninsns); + } + /* Count the number of memory references within the loop body. */ bbs = get_loop_body (loop); subrtx_iterator::array_type array; @@ -15494,6 +15509,19 @@ static void s390_override_options_after_change (void) { s390_default_align (&global_options); + + /* Explicit -funroll-loops turns -munroll-only-small-loops off. */ + if ((OPTION_SET_P (flag_unroll_loops) && flag_unroll_loops) + || (OPTION_SET_P (flag_unroll_all_loops) + && flag_unroll_all_loops)) + { + if (!OPTION_SET_P (unroll_only_small_loops)) + unroll_only_small_loops = 0; + if (!OPTION_SET_P (flag_cunroll_grow_size)) + flag_cunroll_grow_size = 1; + } + else if (!OPTION_SET_P (flag_cunroll_grow_size)) + flag_cunroll_grow_size = flag_peel_loops || optimize >= 3; } static void @@ -15703,6 +15731,9 @@ s390_option_override_internal (struct gcc_options *opts, /* Set the default alignment. */ s390_default_align (opts); + /* Set unroll options. */ + s390_override_options_after_change (); + /* Call target specific restore function to do post-init work. At the moment, this just sets opts->x_s390_cost_pointer. */ s390_function_specific_restore (opts, opts_set, NULL); diff --git a/gcc/config/s390/s390.opt b/gcc/config/s390/s390.opt index 9e8d3bf..c375b9c 100644 --- a/gcc/config/s390/s390.opt +++ b/gcc/config/s390/s390.opt @@ -321,3 +321,7 @@ and the default behavior is to emit separate multiplication and addition instructions for long doubles in vector registers, because measurements show that this improves performance. This option allows overriding it for testing purposes. + +munroll-only-small-loops +Target Undocumented Var(unroll_only_small_loops) Init(0) Save +; Use conservative small loop unrolling. -- cgit v1.1