Addresses of non-weak symbols are non-zero

Use this fact in some foldings of comparisons.  See testcase.
This commit is contained in:
Michael Matz 2016-08-15 05:19:12 +02:00
parent be6d8ffc10
commit d720865fb6
2 changed files with 13 additions and 1 deletions

View File

@ -4979,7 +4979,9 @@ static void expr_cond(void)
expr_lor();
if (tok == '?') {
next();
if ((vtop->r & (VT_VALMASK | VT_LVAL | VT_SYM)) == VT_CONST) {
if ((vtop->r & (VT_VALMASK | VT_LVAL)) == VT_CONST &&
(!(vtop->r & VT_SYM) ||
!(vtop->sym->type.t & VT_WEAK))) {
int saved_nocode_wanted = nocode_wanted;
CType boolean;
int c;

View File

@ -1470,6 +1470,10 @@ typedef int arrtype2[3];
arrtype2 sinit21 = {4};
arrtype2 sinit22 = {5,6,7};
/* Address comparisons of non-weak symbols with zero can be const-folded */
int sinit23[2] = { "astring" ? sizeof("astring") : -1,
&sinit23 ? 42 : -1 };
void init_test(void)
{
int linit1 = 2;
@ -1484,6 +1488,9 @@ void init_test(void)
int linit15[10] = { linit1, linit1 + 1, [6] = linit1 + 2, };
struct linit16 { int a1, a2, a3, a4; } linit16 = { 1, .a3 = 2 };
int linit17 = sizeof(linit17);
int zero = 0;
/* Addresses on non-weak symbols are non-zero, but not the access itself */
int linit18[2] = {&zero ? 1 : -1, zero ? -1 : 1 };
printf("init_test:\n");
@ -1577,6 +1584,9 @@ void init_test(void)
printf("arrtype4: %d %d %d\n", sinit22[0], sinit22[1], sinit22[2]);
printf("arrtype5: %d %d\n", sizeof(sinit21), sizeof(sinit22));
printf("arrtype6: %d\n", sizeof(arrtype2));
printf("sinit23= %d %d\n", sinit23[0], sinit23[1]);
printf("linit18= %d %d\n", linit18[0], linit18[1]);
}