> Preserving the sched state across basic blocks for your case works only if > the BBs are traversed > with the fall through edges coming first. Is that the case? We probably > should have a description > for s390_last_sched_state stating this.
Committed as attached with an additional comment and a check for >= z13. Regards Robin
diff --git a/gcc/config/s390/s390.c b/gcc/config/s390/s390.c index c1a144e..6f1e793 100644 --- a/gcc/config/s390/s390.c +++ b/gcc/config/s390/s390.c @@ -83,6 +83,7 @@ along with GCC; see the file COPYING3. If not see #include "symbol-summary.h" #include "ipa-prop.h" #include "ipa-fnsummary.h" +#include "sched-int.h" /* This file should be included last. */ #include "target-def.h" @@ -14346,6 +14347,28 @@ s390_z10_prevent_earlyload_conflicts (rtx_insn **ready, int *nready_p) ready[0] = tmp; } +/* Returns TRUE if BB is entered via a fallthru edge and all other + incoming edges are less than unlikely. */ +static bool +s390_bb_fallthru_entry_likely (basic_block bb) +{ + edge e, fallthru_edge; + edge_iterator ei; + + if (!bb) + return false; + + fallthru_edge = find_fallthru_edge (bb->preds); + if (!fallthru_edge) + return false; + + FOR_EACH_EDGE (e, ei, bb->preds) + if (e != fallthru_edge + && e->probability >= profile_probability::unlikely ()) + return false; + + return true; +} /* The s390_sched_state variable tracks the state of the current or the last instruction group. @@ -14354,7 +14377,7 @@ s390_z10_prevent_earlyload_conflicts (rtx_insn **ready, int *nready_p) 3 the last group is complete - normal insns 4 the last group was a cracked/expanded insn */ -static int s390_sched_state; +static int s390_sched_state = 0; #define S390_SCHED_STATE_NORMAL 3 #define S390_SCHED_STATE_CRACKED 4 @@ -14764,7 +14787,21 @@ s390_sched_init (FILE *file ATTRIBUTE_UNUSED, { last_scheduled_insn = NULL; memset (last_scheduled_unit_distance, 0, MAX_SCHED_UNITS * sizeof (int)); - s390_sched_state = 0; + + /* If the next basic block is most likely entered via a fallthru edge + we keep the last sched state. Otherwise we start a new group. + The scheduler traverses basic blocks in "instruction stream" ordering + so if we see a fallthru edge here, s390_sched_state will be of its + source block. + + current_sched_info->prev_head is the insn before the first insn of the + block of insns to be scheduled. + */ + rtx_insn *insn = current_sched_info->prev_head + ? NEXT_INSN (current_sched_info->prev_head) : NULL; + basic_block bb = insn ? BLOCK_FOR_INSN (insn) : NULL; + if (s390_tune < PROCESSOR_2964_Z13 || !s390_bb_fallthru_entry_likely (bb)) + s390_sched_state = 0; } /* This target hook implementation for TARGET_LOOP_UNROLL_ADJUST calculates