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small optimization for local declarations without initializations

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This commit is contained in:
Roberto Ierusalimschy 2005-09-30 11:23:33 -03:00
parent ede19c9138
commit 5dbb870815
1 changed files with 12 additions and 9 deletions
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21
lcode.c
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@ -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 ** Code generator for Lua
** See Copyright Notice in lua.h ** See Copyright Notice in lua.h
*/ */
@ -29,14 +29,17 @@
void luaK_nil (FuncState *fs, int from, int n) { void luaK_nil (FuncState *fs, int from, int n) {
Instruction *previous; Instruction *previous;
if (fs->pc > fs->lasttarget && /* no jumps to current position? */ if (fs->pc > fs->lasttarget) { /* no jumps to current position? */
GET_OPCODE(*(previous = &fs->f->code[fs->pc-1])) == OP_LOADNIL) { if (fs->pc == 0) /* function start? */
int pfrom = GETARG_A(*previous); return; /* positions are already clean */
int pto = GETARG_B(*previous); if (GET_OPCODE(*(previous = &fs->f->code[fs->pc-1])) == OP_LOADNIL) {
if (pfrom <= from && from <= pto+1) { /* can connect both? */ int pfrom = GETARG_A(*previous);
if (from+n-1 > pto) int pto = GETARG_B(*previous);
SETARG_B(*previous, from+n-1); if (pfrom <= from && from <= pto+1) { /* can connect both? */
return; 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 */ luaK_codeABC(fs, OP_LOADNIL, from, from+n-1, 0); /* else no optimization */