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Fix __builtin_constant_p(1000/x)

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was incorrectly treated as constant because the vpop removed
all traces of non-constness.
This commit is contained in:
Michael Matz 2016-09-03 23:23:13 +02:00
parent 5bd8aeb917
commit 49bb5a7e06
2 changed files with 27 additions and 0 deletions
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17
tccgen.c
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@ -1787,6 +1787,13 @@ static void gen_opic(int op)
gen_opi(op); gen_opi(op);
} else { } else {
vtop--; vtop--;
/* Ensure vtop isn't marked VT_CONST in case something
up our callchain is interested in const-ness of the
expression. Also make it a non-LVAL if it was,
so that further code can't accidentally generate
a deref (happen only for buggy uses of e.g.
gv() under nocode_wanted). */
vtop->r &= ~(VT_VALMASK | VT_LVAL);
} }
} }
} }
@ -5014,6 +5021,16 @@ static void expr_cond(void)
} }
} }
else { else {
/* XXX This doesn't handle nocode_wanted correctly at all.
It unconditionally calls gv/gvtst and friends. That's
the case for many of the expr_ routines. Currently
that should generate only useless code, but depending
on other operand handling this might also generate
pointer derefs for lvalue conversions whose result
is useless, but nevertheless can lead to segfault.
Somewhen we need to overhaul the whole nocode_wanted
handling. */
if (vtop != vstack) { if (vtop != vstack) {
/* needed to avoid having different registers saved in /* needed to avoid having different registers saved in
each branch */ each branch */

10
tests/tcctest.c
View file

@ -1082,6 +1082,14 @@ static int toupper1(int a)
return TOUPPER(a); return TOUPPER(a);
} }
static unsigned int calc_vm_flags(unsigned int prot)
{
unsigned int prot_bits;
/* This used to segfault in some revisions: */
prot_bits = ((0x1==0x00000001)?(prot&0x1):(prot&0x1)?0x00000001:0);
return prot_bits;
}
void bool_test() void bool_test()
{ {
int *s, a, b, t, f, i; int *s, a, b, t, f, i;
@ -1154,6 +1162,7 @@ void bool_test()
if (toupper1 (i) != TOUPPER (i)) if (toupper1 (i) != TOUPPER (i))
printf("error %d\n", i); printf("error %d\n", i);
} }
printf ("bits = 0x%x\n", calc_vm_flags (0x1));
} }
/* GCC accepts that */ /* GCC accepts that */
@ -2880,6 +2889,7 @@ void builtin_test(void)
printf("res = %d\n", __builtin_constant_p(1 + 2)); printf("res = %d\n", __builtin_constant_p(1 + 2));
printf("res = %d\n", __builtin_constant_p(&constant_p_var)); printf("res = %d\n", __builtin_constant_p(&constant_p_var));
printf("res = %d\n", __builtin_constant_p(constant_p_var)); printf("res = %d\n", __builtin_constant_p(constant_p_var));
printf("res = %d\n", __builtin_constant_p(100000 / constant_p_var));
s = 1; s = 1;
ll = 2; ll = 2;
i = __builtin_choose_expr (1 != 0, ll, s); i = __builtin_choose_expr (1 != 0, ll, s);