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Futher changes to casts

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nocode_wanted can't be used to enforce constant expressions, as it is
set f.ex. by __builtin_constant_p.

A null pointer is unequal to a pointer to any object or function.
Assuming symbols always point to memory, a symbol+constant cast to bool
is always true.
This commit is contained in:
Daniel Glöckner 2008-11-20 22:52:35 +01:00 committed by grischka
parent 5fd6f7bd44
commit 76b02c2a03
1 changed files with 6 additions and 3 deletions
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tcc.c
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@ -5975,7 +5975,7 @@ void force_charshort_cast(int t)
/* cast 'vtop' to 'type'. Casting to bitfields is forbidden. */ /* cast 'vtop' to 'type'. Casting to bitfields is forbidden. */
static void gen_cast(CType *type) static void gen_cast(CType *type)
{ {
int sbt, dbt, sf, df, c; int sbt, dbt, sf, df, c, p;
/* special delayed cast for char/short */ /* special delayed cast for char/short */
/* XXX: in some cases (multiple cascaded casts), it may still /* XXX: in some cases (multiple cascaded casts), it may still
@ -5997,6 +5997,7 @@ static void gen_cast(CType *type)
sf = is_float(sbt); sf = is_float(sbt);
df = is_float(dbt); df = is_float(dbt);
c = (vtop->r & (VT_VALMASK | VT_LVAL | VT_SYM)) == VT_CONST; c = (vtop->r & (VT_VALMASK | VT_LVAL | VT_SYM)) == VT_CONST;
p = (vtop->r & (VT_VALMASK | VT_LVAL | VT_SYM)) == (VT_CONST | VT_SYM);
if (c) { if (c) {
/* constant case: we can do it now */ /* constant case: we can do it now */
/* XXX: in ISOC, cannot do it if error in convert */ /* XXX: in ISOC, cannot do it if error in convert */
@ -6053,6 +6054,9 @@ static void gen_cast(CType *type)
vtop->c.i = ((int)vtop->c.ll << s) >> s; vtop->c.i = ((int)vtop->c.ll << s) >> s;
} }
} }
} else if (p && dbt == VT_BOOL) {
vtop->r = VT_CONST;
vtop->c.i = 1;
} else if (!nocode_wanted) { } else if (!nocode_wanted) {
/* non constant case: generate code */ /* non constant case: generate code */
if (sf && df) { if (sf && df) {
@ -6119,8 +6123,7 @@ static void gen_cast(CType *type)
the lvalue already contains the real type size (see the lvalue already contains the real type size (see
VT_LVAL_xxx constants) */ VT_LVAL_xxx constants) */
} }
} else }
expect("constant expression");
} else if ((dbt & VT_BTYPE) == VT_PTR && !(vtop->r & VT_LVAL)) { } else if ((dbt & VT_BTYPE) == VT_PTR && !(vtop->r & VT_LVAL)) {
/* if we are casting between pointer types, /* if we are casting between pointer types,
we must update the VT_LVAL_xxx size */ we must update the VT_LVAL_xxx size */