From: Jaydeep Patil <jaydeep.pa...@imgtec.com>
Fix negative offset memory addressing. Unconditionally set
DONT_BREAK_DEPENDENCIES in scheduling flags. The code to break
dependencies does not appear to provide a win under any circumstance and
is often harmful. Disable it completely pending further investigation.
gcc/
* config/mips/mips.cc (level, consumer_luid): New static global
variables.
(LEVEL, CONSUMER_LUID): New macros.
(find_reg_born): New static function.
(get_weight): Likewise.
(mips_weight_init_global): Likewise.
(mips_sched_init_global): Likewise.
(mips_weight_evaluation): Likewise.
(mips_evaluation_hook): Likewise.
(mips_set_sched_flags): Likewise. Fix negative offset memory
addressing. Unconditionally set DONT_BREAK_DEPENDENCIES in
scheduling flags. The code to break dependencies does not appear
to provide a win under any circumstance and is often harmful.
Disable it completely pending further investigation.
(mips_weight_finish_global): New static function.
(mips_sched_finish_global): Likewise.
(mips_sched_weight): Likewise.
(mips_sched_reorder_1): Call mips_sched_weight.
(TARGET_SCHED_INIT_GLOBAL, TARGET_SCHED_FINISH_GLOBAL,
TARGET_SCHED_DEPENDENCIES_EVALUATION_HOOK,
TARGET_SCHED_SET_SCHED_FLAGS): New macros.
* config/mips/mips.opt (-msched-weight): New option.
Cherry-picked 0cf2542b41d8102800af180f0b6da1fe55a9d76b,
and f732af3ad1a393d2f2e708f0d7c469a093049d01
from https://github.com/MIPS/gcc
Signed-off-by: Matthew Fortune <matthew.fort...@imgtec.com>
Signed-off-by: Prachi Godbole <prachi.godb...@imgtec.com>
Signed-off-by: Jaydeep Patil <jaydeep.pa...@imgtec.com>
Signed-off-by: Faraz Shahbazker <fshahbaz...@wavecomp.com>
Signed-off-by: Aleksandar Rakic <aleksandar.ra...@htecgroup.com>
---
gcc/config/mips/mips.cc | 239 +++++++++++++++++++++++++++++++++++++++
gcc/config/mips/mips.opt | 3 +
2 files changed, 242 insertions(+)
diff --git a/gcc/config/mips/mips.cc b/gcc/config/mips/mips.cc
index 59781ac7077..894baa2b7a1 100644
--- a/gcc/config/mips/mips.cc
+++ b/gcc/config/mips/mips.cc
@@ -74,6 +74,17 @@ along with GCC; see the file COPYING3. If not see
/* This file should be included last. */
#include "target-def.h"
+/* Definitions used in ready queue reordering for first scheduling pass. */
+
+static int *level = NULL;
+static int *consumer_luid = NULL;
+
+#define LEVEL(INSN) \
+ level[INSN_UID ((INSN))]
+
+#define CONSUMER_LUID(INSN) \
+ consumer_luid[INSN_UID ((INSN))]
+
/* True if X is an UNSPEC wrapper around a SYMBOL_REF or LABEL_REF. */
#define UNSPEC_ADDRESS_P(X) \
(GET_CODE (X) == UNSPEC \
@@ -15540,6 +15551,217 @@ mips_74k_agen_reorder (rtx_insn **ready, int nready)
break;
}
}
+
+/* These functions are called when -msched-weight is set. */
+
+/* Find register born in given X if any. */
+
+static int
+find_reg_born (rtx x)
+{
+ if (GET_CODE (x) == CLOBBER)
+ return 1;
+
+ if (GET_CODE (x) == SET)
+ {
+ if (REG_P (SET_DEST (x)) && reg_mentioned_p (SET_DEST (x), SET_SRC (x)))
+ return 0;
+ return 1;
+ }
+ return 0;
+}
+
+/* Calculate register weight for given INSN. */
+
+static int
+get_weight (rtx insn)
+{
+ int weight = 0;
+ rtx x;
+
+ /* Increment weight for each register born here. */
+ x = PATTERN (insn);
+ weight = find_reg_born (x);
+
+ if (GET_CODE (x) == PARALLEL)
+ {
+ int i;
+ for (i = XVECLEN (x, 0) - 1; i >= 0; i--)
+ {
+ x = XVECEXP (PATTERN (insn), 0, i);
+ weight += find_reg_born (x);
+ }
+ }
+
+ /* Decrement weight for each register that dies here. */
+ for (x = REG_NOTES (insn); x; x = XEXP (x, 1))
+ {
+ if (REG_NOTE_KIND (x) == REG_DEAD || REG_NOTE_KIND (x) == REG_UNUSED)
+ {
+ rtx note = XEXP (x, 0);
+ if (REG_P (note))
+ weight--;
+ }
+ }
+ return weight;
+}
+
+/* TARGET_SCHED_WEIGHT helper function.
+ Allocate and initialize global data. */
+
+static void
+mips_weight_init_global (int old_max_uid)
+{
+ level = (int *) xcalloc (old_max_uid, sizeof (int));
+ consumer_luid = (int *) xcalloc (old_max_uid, sizeof (int));
+}
+
+/* Implement TARGET_SCHED_INIT_GLOBAL. */
+
+static void
+mips_sched_init_global (FILE *dump ATTRIBUTE_UNUSED,
+ int verbose ATTRIBUTE_UNUSED,
+ int old_max_uid)
+{
+ if (!reload_completed && TARGET_SCHED_WEIGHT)
+ mips_weight_init_global (old_max_uid);
+}
+
+/* TARGET_SCHED_WEIGHT helper function. Called for each basic block
+ with dependency chain information in HEAD and TAIL.
+ Calculates LEVEL for each INSN from its forward dependencies
+ and finds out UID of first consumer instruction (CONSUMER_LUID) of INSN. */
+
+static void
+mips_weight_evaluation (rtx_insn *head, rtx_insn *tail)
+{
+ sd_iterator_def sd_it;
+ dep_t dep;
+ rtx_insn *prev_head, *insn;
+ rtx x;
+ prev_head = PREV_INSN (head);
+
+ for (insn = tail; insn != prev_head; insn = PREV_INSN (insn))
+ if (INSN_P (insn))
+ {
+ FOR_EACH_DEP (insn, SD_LIST_FORW, sd_it, dep)
+ {
+ x = DEP_CON (dep);
+ if (! DEBUG_INSN_P (x))
+ {
+ if (LEVEL (x) > LEVEL (insn))
+ LEVEL (insn) = LEVEL (x);
+ CONSUMER_LUID (insn) = INSN_LUID (x);
+ }
+ }
+ LEVEL (insn)++;
+ }
+}
+
+/* Implement TARGET_SCHED_DEPENDENCIES_EVALUATION_HOOK. */
+
+static void
+mips_evaluation_hook (rtx_insn *head, rtx_insn *tail)
+{
+ if (!reload_completed && TARGET_SCHED_WEIGHT)
+ mips_weight_evaluation (head, tail);
+}
+
+/* Implement TARGET_SCHED_SET_SCHED_FLAGS.
+ Enables DONT_BREAK_DEPENDENCIES for the first scheduling pass.
+ It prevents breaking of dependencies on mem/inc pair in the first pass
+ which would otherwise increase stalls. */
+
+static void
+mips_set_sched_flags (spec_info_t spec_info ATTRIBUTE_UNUSED)
+{
+ unsigned int *flags = &(current_sched_info->flags);
+ *flags |= DONT_BREAK_DEPENDENCIES;
+}
+
+static void
+mips_weight_finish_global ()
+{
+ if (level != NULL)
+ free (level);
+
+ if (consumer_luid != NULL)
+ free (consumer_luid);
+}
+
+/* Implement TARGET_SCHED_FINISH_GLOBAL. */
+
+static void
+mips_sched_finish_global (FILE *dump ATTRIBUTE_UNUSED,
+ int verbose ATTRIBUTE_UNUSED)
+{
+ if (!reload_completed && TARGET_SCHED_WEIGHT)
+ mips_weight_finish_global ();
+}
+
+
+/* This is a TARGET_SCHED_WEIGHT (option -msched-weight) helper function
+ which is called during reordering of instructions in the first pass
+ of the scheduler. The function swaps the instruction at (NREADY - 1)
+ of the READY list with another instruction in READY list as per
+ the following algorithm. The scheduler then picks the instruction
+ at READY[NREADY - 1] and schedules it.
+
+ Every instruction is assigned with a value LEVEL.
+ [See: mips_weight_evaluation ().]
+
+ 1. INSN with highest LEVEL is chosen to be scheduled next, ties broken by
+ 1a. Choosing INSN that is used early in the flow or
+ 1b. Choosing INSN with greater INSN_TICK.
+
+ 2. Choose INSN having less LEVEL number iff,
+ 2a. It is used early and
+ 2b. Has greater INSN_TICK and
+ 2c. Contributes less to the register pressure. */
+
+static void
+mips_sched_weight (rtx_insn **ready, int nready)
+{
+ int max_level = LEVEL (ready[nready-1]), toswap = nready-1;
+ int i;
+#define INSN_TICK(INSN) (HID (INSN)->tick)
+
+ for (i = nready - 2; i >= 0; i--)
+ {
+ rtx_insn *insn = ready[i];
+ if (LEVEL (insn) == max_level)
+ {
+ if (INSN_PRIORITY (insn) >= INSN_PRIORITY (ready[toswap]))
+ {
+ if (CONSUMER_LUID (insn) < CONSUMER_LUID (ready[toswap]))
+ toswap = i;
+ }
+ else if (INSN_TICK (insn) > INSN_TICK (ready[toswap]))
+ toswap = i;
+ }
+ if (LEVEL (insn) > max_level)
+ {
+ max_level = LEVEL (insn);
+ toswap = i;
+ }
+ if (LEVEL (insn) < max_level)
+ {
+ if (CONSUMER_LUID (insn) < CONSUMER_LUID (ready[toswap])
+ && INSN_TICK (insn) > INSN_TICK (ready[toswap])
+ && get_weight (insn) < get_weight (ready[toswap]))
+ toswap = i;
+ }
+ }
+
+ if (toswap != (nready-1))
+ {
+ rtx_insn *temp = ready[nready-1];
+ ready[nready-1] = ready[toswap];
+ ready[toswap] = temp;
+ }
+#undef INSN_TICK
+}
+
/* Implement TARGET_SCHED_INIT. */
@@ -15577,6 +15799,11 @@ mips_sched_reorder_1 (FILE *file ATTRIBUTE_UNUSED, int
verbose ATTRIBUTE_UNUSED,
if (TUNE_74K)
mips_74k_agen_reorder (ready, *nreadyp);
+
+ if (! reload_completed
+ && TARGET_SCHED_WEIGHT
+ && *nreadyp > 1)
+ mips_sched_weight (ready, *nreadyp);
}
/* Implement TARGET_SCHED_REORDER. */
@@ -24004,6 +24231,18 @@ mips_bit_clear_p (enum machine_mode mode, unsigned
HOST_WIDE_INT m)
#undef TARGET_C_MODE_FOR_FLOATING_TYPE
#define TARGET_C_MODE_FOR_FLOATING_TYPE mips_c_mode_for_floating_type
+#undef TARGET_SCHED_INIT_GLOBAL
+#define TARGET_SCHED_INIT_GLOBAL mips_sched_init_global
+
+#undef TARGET_SCHED_FINISH_GLOBAL
+#define TARGET_SCHED_FINISH_GLOBAL mips_sched_finish_global
+
+#undef TARGET_SCHED_DEPENDENCIES_EVALUATION_HOOK
+#define TARGET_SCHED_DEPENDENCIES_EVALUATION_HOOK mips_evaluation_hook
+
+#undef TARGET_SCHED_SET_SCHED_FLAGS
+#define TARGET_SCHED_SET_SCHED_FLAGS mips_set_sched_flags
+
struct gcc_target targetm = TARGET_INITIALIZER;
#include "gt-mips.h"
diff --git a/gcc/config/mips/mips.opt b/gcc/config/mips/mips.opt
index 21a32df1a40..345d95f311a 100644
--- a/gcc/config/mips/mips.opt
+++ b/gcc/config/mips/mips.opt
@@ -516,3 +516,6 @@ Use Loongson EXTension (EXT) instructions.
mloongson-ext2
Target Var(TARGET_LOONGSON_EXT2)
Use Loongson EXTension R2 (EXT2) instructions.
+
+msched-weight
+Target Var(TARGET_SCHED_WEIGHT) Undocumented
--
2.34.1
