From 0038cda620970b0382deadbeb12b8140bf402fbc Mon Sep 17 00:00:00 2001
From: Richard Henderson <richard.henderson@linaro.org>
Date: Wed, 3 Mar 2021 21:41:19 -0500
Subject: [PATCH] tcg/optimize: Adjust TempOptInfo allocation

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.

Backports 8f17a975e60b773d7c366a81c0d9bbe304f30859
---
 qemu/tcg/optimize.c | 47 +++++++++++++++++++++++++++------------------
 1 file changed, 28 insertions(+), 19 deletions(-)

diff --git a/qemu/tcg/optimize.c b/qemu/tcg/optimize.c
index d6cf8488..b2bb368d 100644
--- a/qemu/tcg/optimize.c
+++ b/qemu/tcg/optimize.c
@@ -92,30 +92,35 @@ static void reset_all_temps(TCGContext *s, int nb_temps)
 /* Initialize and activate a temporary.  */
 static void init_ts_info(TCGContext *s, TCGTemp *ts)
 {
-    TempOptInfo *temps = s->temps2;
     TCGTempSet *temps_used = &s->temps2_used;
 
+    TempOptInfo *ti;
     size_t idx = temp_idx(s, ts);
-    if (!test_bit(idx, temps_used->l)) {
-        TempOptInfo *ti = &temps[idx];
 
+    if (test_bit(idx, temps_used->l)) {
+        return;
+    }
+    set_bit(idx, temps_used->l);
+
+    ti = ts->state_ptr;
+    if (ti == NULL) {
+        ti = tcg_malloc(s, sizeof(TempOptInfo));
         ts->state_ptr = ti;
-        ti->next_copy = ts;
-        ti->prev_copy = ts;
+    }
+
+    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;
+        }
+    } else {
         ti->is_const = false;
         ti->mask = -1;
-        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;
-        }
-        set_bit(idx, temps_used->l);
     }
 }
 
@@ -610,7 +615,7 @@ static bool swap_commutative2(TCGContext *s, 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;
 
     /* Array VALS has an element for each temp.
@@ -622,9 +627,13 @@ void tcg_optimize(TCGContext *s)
     nb_globals = s->nb_globals;
     reset_all_temps(s, 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 = &s->tcg_op_defs[opc];