lua

commit 5dbb87081520de93b54f35969ca84598f70a5673
parent ede19c91385e9d30080048e744cf2a363eae968c
Author: Roberto Ierusalimschy <roberto@inf.puc-rio.br>
Date:   Fri, 30 Sep 2005 11:23:11 -0300

small optimization for local declarations without initializations

Diffstat:
M
lcode.c
 | 
21
++++++++++++---------

1 file changed, 12 insertions(+), 9 deletions(-)
diff --git a/lcode.c b/lcode.c
@@ -1,5 +1,5 @@
 /*
-** $Id: lcode.c,v 2.15 2005/08/17 18:32:09 roberto Exp $
+** $Id: lcode.c,v 2.16 2005/08/29 20:49:21 roberto Exp roberto $
 ** Code generator for Lua
 ** See Copyright Notice in lua.h
 */
@@ -29,14 +29,17 @@
 
 void luaK_nil (FuncState *fs, int from, int n) {
   Instruction *previous;
-  if (fs->pc > fs->lasttarget &&  /* no jumps to current position? */
-      GET_OPCODE(*(previous = &fs->f->code[fs->pc-1])) == OP_LOADNIL) {
-    int pfrom = GETARG_A(*previous);
-    int pto = GETARG_B(*previous);
-    if (pfrom <= from && from <= pto+1) {  /* can connect both? */
-      if (from+n-1 > pto)
-        SETARG_B(*previous, from+n-1);
-      return;
+  if (fs->pc > fs->lasttarget) {  /* no jumps to current position? */
+    if (fs->pc == 0)  /* function start? */
+      return;  /* positions are already clean */
+    if (GET_OPCODE(*(previous = &fs->f->code[fs->pc-1])) == OP_LOADNIL) {
+      int pfrom = GETARG_A(*previous);
+      int pto = GETARG_B(*previous);
+      if (pfrom <= from && from <= pto+1) {  /* can connect both? */
+        if (from+n-1 > pto)
+          SETARG_B(*previous, from+n-1);
+        return;
+      }
     }
   }
   luaK_codeABC(fs, OP_LOADNIL, from, from+n-1, 0);  /* else no optimization */