[Qemu-devel] [PATCH v2] tcg/optimize: fold constant test in tcg_opt_gen_mov

[Aurelien Jarno]

Most of the calls to tcg_opt_gen_mov are preceeded by a test to check if
the source temp is a constant. Fold that into the tcg_opt_gen_mov
function.

Cc: Richard Henderson <address@hidden>
Signed-off-by: Aurelien Jarno <address@hidden>
---
 tcg/optimize.c | 89 ++++++++++++++++++++++++----------------------------------
 1 file changed, 36 insertions(+), 53 deletions(-)

A version with the check for constants and copies swapped in case you
prefer to merge this one.

diff --git a/tcg/optimize.c b/tcg/optimize.c
index d5c0398..859a6c1 100644
--- a/tcg/optimize.c
+++ b/tcg/optimize.c
@@ -193,6 +193,28 @@ static bool temps_are_copies(TCGArg arg1, TCGArg arg2)
     return false;
 }
 
+static void tcg_opt_gen_movi(TCGContext *s, TCGOp *op, TCGArg *args,
+                             TCGArg dst, TCGArg val)
+{
+    TCGOpcode new_op = op_to_movi(op->opc);
+    tcg_target_ulong mask;
+
+    op->opc = new_op;
+
+    reset_temp(dst);
+    temps[dst].state = TCG_TEMP_CONST;
+    temps[dst].val = val;
+    mask = val;
+    if (TCG_TARGET_REG_BITS > 32 && new_op == INDEX_op_mov_i32) {
+        /* High bits of the destination are now garbage.  */
+        mask |= ~0xffffffffull;
+    }
+    temps[dst].mask = mask;
+
+    args[0] = dst;
+    args[1] = val;
+}
+
 static void tcg_opt_gen_mov(TCGContext *s, TCGOp *op, TCGArg *args,
                             TCGArg dst, TCGArg src)
 {
@@ -201,6 +223,11 @@ static void tcg_opt_gen_mov(TCGContext *s, TCGOp *op, 
TCGArg *args,
         return;
     }
 
+    if (temps[src].state == TCG_TEMP_CONST) {
+        tcg_opt_gen_movi(s, op, args, dst, temps[src].val);
+        return;
+    }
+
     TCGOpcode new_op = op_to_mov(op->opc);
     tcg_target_ulong mask;
 
@@ -233,28 +260,6 @@ static void tcg_opt_gen_mov(TCGContext *s, TCGOp *op, 
TCGArg *args,
     args[1] = src;
 }
 
-static void tcg_opt_gen_movi(TCGContext *s, TCGOp *op, TCGArg *args,
-                             TCGArg dst, TCGArg val)
-{
-    TCGOpcode new_op = op_to_movi(op->opc);
-    tcg_target_ulong mask;
-
-    op->opc = new_op;
-
-    reset_temp(dst);
-    temps[dst].state = TCG_TEMP_CONST;
-    temps[dst].val = val;
-    mask = val;
-    if (TCG_TARGET_REG_BITS > 32 && new_op == INDEX_op_mov_i32) {
-        /* High bits of the destination are now garbage.  */
-        mask |= ~0xffffffffull;
-    }
-    temps[dst].mask = mask;
-
-    args[0] = dst;
-    args[1] = val;
-}
-
 static TCGArg do_constant_folding_2(TCGOpcode op, TCGArg x, TCGArg y)
 {
     uint64_t l64, h64;
@@ -780,7 +785,8 @@ static void tcg_constant_folding(TCGContext *s)
             if (temps[args[1]].state != TCG_TEMP_CONST
                 && temps[args[2]].state == TCG_TEMP_CONST
                 && temps[args[2]].val == 0) {
-                goto do_mov3;
+                tcg_opt_gen_mov(s, op, args, args[0], args[1]);
+                continue;
             }
             break;
         CASE_OP_32_64(and):
@@ -789,12 +795,10 @@ static void tcg_constant_folding(TCGContext *s)
             if (temps[args[1]].state != TCG_TEMP_CONST
                 && temps[args[2]].state == TCG_TEMP_CONST
                 && temps[args[2]].val == -1) {
-                goto do_mov3;
+                tcg_opt_gen_mov(s, op, args, args[0], args[1]);
+                continue;
             }
             break;
-        do_mov3:
-            tcg_opt_gen_mov(s, op, args, args[0], args[1]);
-            continue;
         default:
             break;
         }
@@ -948,12 +952,7 @@ static void tcg_constant_folding(TCGContext *s)
         }
         if (affected == 0) {
             assert(nb_oargs == 1);
-            if (temps[args[1]].state != TCG_TEMP_CONST) {
-                tcg_opt_gen_mov(s, op, args, args[0], args[1]);
-            } else {
-                tcg_opt_gen_movi(s, op, args,
-                                 args[0], temps[args[1]].val);
-            }
+            tcg_opt_gen_mov(s, op, args, args[0], args[1]);
             continue;
         }
 
@@ -978,12 +977,7 @@ static void tcg_constant_folding(TCGContext *s)
         CASE_OP_32_64(or):
         CASE_OP_32_64(and):
             if (temps_are_copies(args[1], args[2])) {
-                if (temps[args[1]].state != TCG_TEMP_CONST) {
-                    tcg_opt_gen_mov(s, op, args, args[0], args[1]);
-                } else {
-                    tcg_opt_gen_movi(s, op, args,
-                                     args[0], temps[args[1]].val);
-                }
+                tcg_opt_gen_mov(s, op, args, args[0], args[1]);
                 continue;
             }
             break;
@@ -1010,14 +1004,8 @@ static void tcg_constant_folding(TCGContext *s)
            allocator where needed and possible.  Also detect copies. */
         switch (opc) {
         CASE_OP_32_64(mov):
-            if (temps[args[1]].state != TCG_TEMP_CONST) {
-                tcg_opt_gen_mov(s, op, args, args[0], args[1]);
-                break;
-            }
-            /* Source argument is constant.  Rewrite the operation and
-               let movi case handle it. */
-            args[1] = temps[args[1]].val;
-            /* fallthrough */
+            tcg_opt_gen_mov(s, op, args, args[0], args[1]);
+            break;
         CASE_OP_32_64(movi):
             tcg_opt_gen_movi(s, op, args, args[0], args[1]);
             break;
@@ -1111,12 +1099,7 @@ static void tcg_constant_folding(TCGContext *s)
         CASE_OP_32_64(movcond):
             tmp = do_constant_folding_cond(opc, args[1], args[2], args[5]);
             if (tmp != 2) {
-                if (temps[args[4-tmp]].state == TCG_TEMP_CONST) {
-                    tcg_opt_gen_movi(s, op, args,
-                                     args[0], temps[args[4-tmp]].val);
-                } else {
-                    tcg_opt_gen_mov(s, op, args, args[0], args[4-tmp]);
-                }
+                tcg_opt_gen_mov(s, op, args, args[0], args[4-tmp]);
                 break;
             }
             goto do_default;
-- 
2.1.4