From 3eefdf2b5885dca36eefa200862c661654519162 Mon Sep 17 00:00:00 2001
From: Richard Henderson <richard.henderson@linaro.org>
Date: Wed, 25 Aug 2021 11:06:43 -0700
Subject: [PATCH] tcg/optimize: Split out fold_mb, fold_qemu_{ld,st}
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This puts the separate mb optimization into the same framework
as the others.  While fold_qemu_{ld,st} are currently identical,
that won't last as more code gets moved.

Reviewed-by: Luis Pires <luis.pires@eldorado.org.br>
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
---
 tcg/optimize.c | 89 +++++++++++++++++++++++++++++++++-------------------------
 1 file changed, 51 insertions(+), 38 deletions(-)

diff --git a/tcg/optimize.c b/tcg/optimize.c
index 699476e2f1..159a5a9ee5 100644
--- a/tcg/optimize.c
+++ b/tcg/optimize.c
@@ -692,6 +692,44 @@ static bool fold_call(OptContext *ctx, TCGOp *op)
     return true;
 }
 
+static bool fold_mb(OptContext *ctx, TCGOp *op)
+{
+    /* Eliminate duplicate and redundant fence instructions.  */
+    if (ctx->prev_mb) {
+        /*
+         * Merge two barriers of the same type into one,
+         * or a weaker barrier into a stronger one,
+         * or two weaker barriers into a stronger one.
+         *   mb X; mb Y => mb X|Y
+         *   mb; strl => mb; st
+         *   ldaq; mb => ld; mb
+         *   ldaq; strl => ld; mb; st
+         * Other combinations are also merged into a strong
+         * barrier.  This is stricter than specified but for
+         * the purposes of TCG is better than not optimizing.
+         */
+        ctx->prev_mb->args[0] |= op->args[0];
+        tcg_op_remove(ctx->tcg, op);
+    } else {
+        ctx->prev_mb = op;
+    }
+    return true;
+}
+
+static bool fold_qemu_ld(OptContext *ctx, TCGOp *op)
+{
+    /* Opcodes that touch guest memory stop the mb optimization.  */
+    ctx->prev_mb = NULL;
+    return false;
+}
+
+static bool fold_qemu_st(OptContext *ctx, TCGOp *op)
+{
+    /* Opcodes that touch guest memory stop the mb optimization.  */
+    ctx->prev_mb = NULL;
+    return false;
+}
+
 /* Propagate constants and copies, fold constant expressions. */
 void tcg_optimize(TCGContext *s)
 {
@@ -1599,6 +1637,19 @@ void tcg_optimize(TCGContext *s)
             }
             break;
 
+        case INDEX_op_mb:
+            done = fold_mb(&ctx, op);
+            break;
+        case INDEX_op_qemu_ld_i32:
+        case INDEX_op_qemu_ld_i64:
+            done = fold_qemu_ld(&ctx, op);
+            break;
+        case INDEX_op_qemu_st_i32:
+        case INDEX_op_qemu_st8_i32:
+        case INDEX_op_qemu_st_i64:
+            done = fold_qemu_st(&ctx, op);
+            break;
+
         default:
             break;
         }
@@ -1606,43 +1657,5 @@ void tcg_optimize(TCGContext *s)
         if (!done) {
             finish_folding(&ctx, op);
         }
-
-        /* Eliminate duplicate and redundant fence instructions.  */
-        if (ctx.prev_mb) {
-            switch (opc) {
-            case INDEX_op_mb:
-                /* Merge two barriers of the same type into one,
-                 * or a weaker barrier into a stronger one,
-                 * or two weaker barriers into a stronger one.
-                 *   mb X; mb Y => mb X|Y
-                 *   mb; strl => mb; st
-                 *   ldaq; mb => ld; mb
-                 *   ldaq; strl => ld; mb; st
-                 * Other combinations are also merged into a strong
-                 * barrier.  This is stricter than specified but for
-                 * the purposes of TCG is better than not optimizing.
-                 */
-                ctx.prev_mb->args[0] |= op->args[0];
-                tcg_op_remove(s, op);
-                break;
-
-            default:
-                /* Opcodes that end the block stop the optimization.  */
-                if ((def->flags & TCG_OPF_BB_END) == 0) {
-                    break;
-                }
-                /* fallthru */
-            case INDEX_op_qemu_ld_i32:
-            case INDEX_op_qemu_ld_i64:
-            case INDEX_op_qemu_st_i32:
-            case INDEX_op_qemu_st8_i32:
-            case INDEX_op_qemu_st_i64:
-                /* Opcodes that touch guest memory stop the optimization.  */
-                ctx.prev_mb = NULL;
-                break;
-            }
-        } else if (opc == INDEX_op_mb) {
-            ctx.prev_mb = op;
-        }
     }
 }
-- 
2.11.4.GIT