From 8f17a975e60b773d7c366a81c0d9bbe304f30859 Mon Sep 17 00:00:00 2001
From: Richard Henderson <richard.henderson@linaro.org>
Date: Mon, 30 Mar 2020 19:52:02 -0700
Subject: [PATCH] tcg/optimize: Adjust TempOptInfo allocation
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Do not allocate a large block for indexing.  Instead, allocate
for each temporary as they are seen.

In general, this will use less memory, if we consider that most
TBs do not touch every target register.  This also allows us to
allocate TempOptInfo for new temps created during optimization.

Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
---
 tcg/optimize.c | 60 ++++++++++++++++++++++++++++----------------------
 1 file changed, 34 insertions(+), 26 deletions(-)

diff --git a/tcg/optimize.c b/tcg/optimize.c
index e42f9c89a8..49bf1386c7 100644
--- a/tcg/optimize.c
+++ b/tcg/optimize.c
@@ -89,35 +89,41 @@ static void reset_temp(TCGArg arg)
 }
 
 /* Initialize and activate a temporary.  */
-static void init_ts_info(TempOptInfo *infos,
-                         TCGTempSet *temps_used, TCGTemp *ts)
+static void init_ts_info(TCGTempSet *temps_used, TCGTemp *ts)
 {
     size_t idx = temp_idx(ts);
-    if (!test_bit(idx, temps_used->l)) {
-        TempOptInfo *ti = &infos[idx];
+    TempOptInfo *ti;
 
+    if (test_bit(idx, temps_used->l)) {
+        return;
+    }
+    set_bit(idx, temps_used->l);
+
+    ti = ts->state_ptr;
+    if (ti == NULL) {
+        ti = tcg_malloc(sizeof(TempOptInfo));
         ts->state_ptr = ti;
-        ti->next_copy = ts;
-        ti->prev_copy = ts;
-        if (ts->kind == TEMP_CONST) {
-            ti->is_const = true;
-            ti->val = ti->mask = ts->val;
-            if (TCG_TARGET_REG_BITS > 32 && ts->type == TCG_TYPE_I32) {
-                /* High bits of a 32-bit quantity are garbage.  */
-                ti->mask |= ~0xffffffffull;
-            }
-        } else {
-            ti->is_const = false;
-            ti->mask = -1;
+    }
+
+    ti->next_copy = ts;
+    ti->prev_copy = ts;
+    if (ts->kind == TEMP_CONST) {
+        ti->is_const = true;
+        ti->val = ts->val;
+        ti->mask = ts->val;
+        if (TCG_TARGET_REG_BITS > 32 && ts->type == TCG_TYPE_I32) {
+            /* High bits of a 32-bit quantity are garbage.  */
+            ti->mask |= ~0xffffffffull;
         }
-        set_bit(idx, temps_used->l);
+    } else {
+        ti->is_const = false;
+        ti->mask = -1;
     }
 }
 
-static void init_arg_info(TempOptInfo *infos,
-                          TCGTempSet *temps_used, TCGArg arg)
+static void init_arg_info(TCGTempSet *temps_used, TCGArg arg)
 {
-    init_ts_info(infos, temps_used, arg_temp(arg));
+    init_ts_info(temps_used, arg_temp(arg));
 }
 
 static TCGTemp *find_better_copy(TCGContext *s, TCGTemp *ts)
@@ -604,9 +610,8 @@ static bool swap_commutative2(TCGArg *p1, TCGArg *p2)
 /* Propagate constants and copies, fold constant expressions. */
 void tcg_optimize(TCGContext *s)
 {
-    int nb_temps, nb_globals;
+    int nb_temps, nb_globals, i;
     TCGOp *op, *op_next, *prev_mb = NULL;
-    TempOptInfo *infos;
     TCGTempSet temps_used;
 
     /* Array VALS has an element for each temp.
@@ -616,12 +621,15 @@ void tcg_optimize(TCGContext *s)
 
     nb_temps = s->nb_temps;
     nb_globals = s->nb_globals;
+
     bitmap_zero(temps_used.l, nb_temps);
-    infos = tcg_malloc(sizeof(TempOptInfo) * nb_temps);
+    for (i = 0; i < nb_temps; ++i) {
+        s->temps[i].state_ptr = NULL;
+    }
 
     QTAILQ_FOREACH_SAFE(op, &s->ops, link, op_next) {
         uint64_t mask, partmask, affected, tmp;
-        int nb_oargs, nb_iargs, i;
+        int nb_oargs, nb_iargs;
         TCGOpcode opc = op->opc;
         const TCGOpDef *def = &tcg_op_defs[opc];
 
@@ -633,14 +641,14 @@ void tcg_optimize(TCGContext *s)
             for (i = 0; i < nb_oargs + nb_iargs; i++) {
                 TCGTemp *ts = arg_temp(op->args[i]);
                 if (ts) {
-                    init_ts_info(infos, &temps_used, ts);
+                    init_ts_info(&temps_used, ts);
                 }
             }
         } else {
             nb_oargs = def->nb_oargs;
             nb_iargs = def->nb_iargs;
             for (i = 0; i < nb_oargs + nb_iargs; i++) {
-                init_arg_info(infos, &temps_used, op->args[i]);
+                init_arg_info(&temps_used, op->args[i]);
             }
         }