Fix SF bug 1441486: bad unary minus folding in compiler.
diff --git a/Python/ast.c b/Python/ast.c
index 6fd1ebe..cd0649e 100644
--- a/Python/ast.c
+++ b/Python/ast.c
@@ -1484,6 +1484,57 @@
}
static expr_ty
+ast_for_factor(struct compiling *c, const node *n)
+{
+ node *pfactor, *ppower, *patom, *pnum;
+ expr_ty expression;
+
+ /* If the unary - operator is applied to a constant, don't generate
+ a UNARY_NEGATIVE opcode. Just store the approriate value as a
+ constant. The peephole optimizer already does something like
+ this but it doesn't handle the case where the constant is
+ (sys.maxint - 1). In that case, we want a PyIntObject, not a
+ PyLongObject.
+ */
+ if (TYPE(CHILD(n, 0)) == MINUS
+ && NCH(n) == 2
+ && TYPE((pfactor = CHILD(n, 1))) == factor
+ && NCH(pfactor) == 1
+ && TYPE((ppower = CHILD(pfactor, 0))) == power
+ && NCH(ppower) == 1
+ && TYPE((patom = CHILD(ppower, 0))) == atom
+ && TYPE((pnum = CHILD(patom, 0))) == NUMBER) {
+ char *s = PyObject_MALLOC(strlen(STR(pnum)) + 2);
+ if (s == NULL)
+ return NULL;
+ s[0] = '-';
+ strcpy(s + 1, STR(pnum));
+ PyObject_FREE(STR(pnum));
+ STR(pnum) = s;
+ return ast_for_atom(c, patom);
+ }
+
+ expression = ast_for_expr(c, CHILD(n, 1));
+ if (!expression)
+ return NULL;
+
+ switch (TYPE(CHILD(n, 0))) {
+ case PLUS:
+ return UnaryOp(UAdd, expression, LINENO(n), n->n_col_offset,
+ c->c_arena);
+ case MINUS:
+ return UnaryOp(USub, expression, LINENO(n), n->n_col_offset,
+ c->c_arena);
+ case TILDE:
+ return UnaryOp(Invert, expression, LINENO(n),
+ n->n_col_offset, c->c_arena);
+ }
+ PyErr_Format(PyExc_SystemError, "unhandled factor: %d",
+ TYPE(CHILD(n, 0)));
+ return NULL;
+}
+
+static expr_ty
ast_for_power(struct compiling *c, const node *n)
{
/* power: atom trailer* ('**' factor)*
@@ -1662,30 +1713,12 @@
}
return Yield(exp, LINENO(n), n->n_col_offset, c->c_arena);
}
- case factor: {
- expr_ty expression;
-
+ case factor:
if (NCH(n) == 1) {
n = CHILD(n, 0);
goto loop;
}
-
- expression = ast_for_expr(c, CHILD(n, 1));
- if (!expression)
- return NULL;
-
- switch (TYPE(CHILD(n, 0))) {
- case PLUS:
- return UnaryOp(UAdd, expression, LINENO(n), n->n_col_offset, c->c_arena);
- case MINUS:
- return UnaryOp(USub, expression, LINENO(n), n->n_col_offset, c->c_arena);
- case TILDE:
- return UnaryOp(Invert, expression, LINENO(n), n->n_col_offset, c->c_arena);
- }
- PyErr_Format(PyExc_SystemError, "unhandled factor: %d",
- TYPE(CHILD(n, 0)));
- break;
- }
+ return ast_for_factor(c, n);
case power:
return ast_for_power(c, n);
default: