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integer exponentiation with negative exponent is invalid

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Roberto Ierusalimschy
2013-12-16 12:30:22 -02:00
parent 1a19893d6f
commit a8f8c7fd80
4 changed files with 32 additions and 30 deletions
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10
lcode.c
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@@ -1,5 +1,5 @@
/*
** $Id: lcode.c,v 2.71 2013/06/25 18:57:18 roberto Exp roberto $
** $Id: lcode.c,v 2.72 2013/08/30 16:01:37 roberto Exp roberto $
** Code generator for Lua
** See Copyright Notice in lua.h
*/
@@ -754,12 +754,14 @@ static int constfolding (OpCode op, expdesc *e1, expdesc *e2) {
TValue v1, v2, res;
lua_Integer i;
if (!tonumeral(e1, &v1) || !tonumeral(e2, &v2))
return 0;
return 0; /* non-numeric operands */
if (op == OP_IDIV &&
(!tointeger(&v1, &i) || !tointeger(&v2, &i) || i == 0))
return 0; /* avoid division by 0 and conversion errors */
if (op == OP_MOD && ttisinteger(&v1) && ttisinteger(&v2) && ivalue(&v2) == 0)
return 0; /* avoid module by 0 at compile time */
if (ttisinteger(&v1) && ttisinteger(&v2) && /* for integer operations... */
((op == OP_MOD && ivalue(&v2) == 0) || /* ...avoid module by 0... */
(op == OP_POW && ivalue(&v2) < 0))) /* ...and negative exponents */
return 0;
luaO_arith(NULL, op - OP_ADD + LUA_OPADD, &v1, &v2, &res);
if (ttisinteger(&res)) {
e1->k = VKINT;