/* This checks if enums needing 8 bit but only having positive values are correctly zero extended (instead of sign extended) when stored into/loaded from a 8 bit bit-field of enum type (which itself is implementation defined, so isn't necessarily supported by all other compilers). */enum tree_code { SOME_CODE = 148, /* has bit 7 set, and hence all further enum values as well */ LAST_AND_UNUSED_TREE_CODE};typedef union tree_node *tree;struct tree_common{ union tree_node *chain; union tree_node *type; enum tree_code code : 8; unsigned side_effects_flag : 1;};union tree_node{ struct tree_common common; };enum c_tree_code { C_DUMMY_TREE_CODE = LAST_AND_UNUSED_TREE_CODE, STMT_EXPR, LAST_C_TREE_CODE};enum cplus_tree_code { CP_DUMMY_TREE_CODE = LAST_C_TREE_CODE, AMBIG_CONV, LAST_CPLUS_TREE_CODE};extern int printf(const char *, ...);int blah(){return 0;}int convert_like_real (tree convs){ switch (((enum tree_code) (convs)->common.code)) { case AMBIG_CONV: /* This has bit 7 set, which must not be the sign bit in tree_common.code, i.e. the bitfield must be somehow marked unsigned. */ return blah(); default: break; }; printf("unsigned enum bit-fields broken\n"); return 0;}int main(){ union tree_node convs; convs.common.code = AMBIG_CONV; convert_like_real (&convs); return 0;}
/* This checks if enums needing 8 bit but only having positive
values are correctly zero extended (instead of sign extended)
when stored into/loaded from a 8 bit bit-field of enum type (which
itself is implementation defined, so isn't necessarily supported by all
other compilers). */
enum tree_code {
SOME_CODE = 148, /* has bit 7 set, and hence all further enum values as well */
LAST_AND_UNUSED_TREE_CODE
};
typedef union tree_node *tree;
struct tree_common
{
union tree_node *chain;
union tree_node *type;
enum tree_code code : 8;
unsigned side_effects_flag : 1;
};
union tree_node
{
struct tree_common common;
};
enum c_tree_code {
C_DUMMY_TREE_CODE = LAST_AND_UNUSED_TREE_CODE,
STMT_EXPR,
LAST_C_TREE_CODE
};
enum cplus_tree_code {
CP_DUMMY_TREE_CODE = LAST_C_TREE_CODE,
AMBIG_CONV,
LAST_CPLUS_TREE_CODE
};
extern int printf(const char *, ...);
int blah(){return 0;}
int convert_like_real (tree convs)
{
switch (((enum tree_code) (convs)->common.code))
{
case AMBIG_CONV: /* This has bit 7 set, which must not be the sign
bit in tree_common.code, i.e. the bitfield must
be somehow marked unsigned. */
return blah();
default:
break;
};
printf("unsigned enum bit-fields broken\n");
return 0;
}
int main()
{
union tree_node convs;
convs.common.code = AMBIG_CONV;
convert_like_real (&convs);
return 0;
}