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Applied patch to fp-bit.c
- To: gcc-patches@gcc.gnu.org
- Subject: Applied patch to fp-bit.c
- From: Bernd Schmidt <bernds@cygnus.co.uk>
- Date: Sun, 29 Aug 1999 11:51:21 +0100 (BST)
I've applied the following patch to gcc. While chasing another problem, I
noticed that we had potential problems wrt. aliasing in fp-bit.c. While the
code will not be broken by -fstrict-aliasing, there are other aliasing checks
in gcc (MEM_IN_STRUCT vs. MEM_SCALAR_P tests) which can cause this type of
code to be miscompiled.
Approved by Jim Wilson.
Bernd
* fp-bit.c (add, sub, multiply, divide, compare, _eq_f2, _ne_f2,
_gt_f2, _ge_f2, _lt_f2, _le_f2, float_to_si, float_to_usi, negate,
sf_to_df, df_to_sf): Likewise.
Index: config/fp-bit.c
===================================================================
RCS file: /cvs/cvsfiles/devo/gcc/config/fp-bit.c,v
retrieving revision 1.57
diff -u -p -r1.57 fp-bit.c
--- config/fp-bit.c 1998/11/23 07:32:12 1.57
+++ config/fp-bit.c 1999/08/26 20:23:14
@@ -780,10 +780,14 @@ add (FLO_type arg_a, FLO_type arg_b)
fp_number_type b;
fp_number_type tmp;
fp_number_type *res;
+ FLO_union_type au, bu;
- unpack_d ((FLO_union_type *) & arg_a, &a);
- unpack_d ((FLO_union_type *) & arg_b, &b);
+ au.value = arg_a;
+ bu.value = arg_b;
+ unpack_d (&au, &a);
+ unpack_d (&bu, &b);
+
res = _fpadd_parts (&a, &b, &tmp);
return pack_d (res);
@@ -796,9 +800,13 @@ sub (FLO_type arg_a, FLO_type arg_b)
fp_number_type b;
fp_number_type tmp;
fp_number_type *res;
+ FLO_union_type au, bu;
+
+ au.value = arg_a;
+ bu.value = arg_b;
- unpack_d ((FLO_union_type *) & arg_a, &a);
- unpack_d ((FLO_union_type *) & arg_b, &b);
+ unpack_d (&au, &a);
+ unpack_d (&bu, &b);
b.sign ^= 1;
@@ -986,10 +994,14 @@ multiply (FLO_type arg_a, FLO_type arg_b
fp_number_type b;
fp_number_type tmp;
fp_number_type *res;
+ FLO_union_type au, bu;
- unpack_d ((FLO_union_type *) & arg_a, &a);
- unpack_d ((FLO_union_type *) & arg_b, &b);
+ au.value = arg_a;
+ bu.value = arg_b;
+ unpack_d (&au, &a);
+ unpack_d (&bu, &b);
+
res = _fpmul_parts (&a, &b, &tmp);
return pack_d (res);
@@ -1092,9 +1104,13 @@ divide (FLO_type arg_a, FLO_type arg_b)
fp_number_type a;
fp_number_type b;
fp_number_type *res;
+ FLO_union_type au, bu;
+
+ au.value = arg_a;
+ bu.value = arg_b;
- unpack_d ((FLO_union_type *) & arg_a, &a);
- unpack_d ((FLO_union_type *) & arg_b, &b);
+ unpack_d (&au, &a);
+ unpack_d (&bu, &b);
res = _fpdiv_parts (&a, &b);
@@ -1195,10 +1211,14 @@ compare (FLO_type arg_a, FLO_type arg_b)
{
fp_number_type a;
fp_number_type b;
+ FLO_union_type au, bu;
- unpack_d ((FLO_union_type *) & arg_a, &a);
- unpack_d ((FLO_union_type *) & arg_b, &b);
+ au.value = arg_a;
+ bu.value = arg_b;
+ unpack_d (&au, &a);
+ unpack_d (&bu, &b);
+
return __fpcmp_parts (&a, &b);
}
#endif
@@ -1213,9 +1233,13 @@ _eq_f2 (FLO_type arg_a, FLO_type arg_b)
{
fp_number_type a;
fp_number_type b;
+ FLO_union_type au, bu;
+
+ au.value = arg_a;
+ bu.value = arg_b;
- unpack_d ((FLO_union_type *) & arg_a, &a);
- unpack_d ((FLO_union_type *) & arg_b, &b);
+ unpack_d (&au, &a);
+ unpack_d (&bu, &b);
if (isnan (&a) || isnan (&b))
return 1; /* false, truth == 0 */
@@ -1230,10 +1254,14 @@ _ne_f2 (FLO_type arg_a, FLO_type arg_b)
{
fp_number_type a;
fp_number_type b;
+ FLO_union_type au, bu;
- unpack_d ((FLO_union_type *) & arg_a, &a);
- unpack_d ((FLO_union_type *) & arg_b, &b);
+ au.value = arg_a;
+ bu.value = arg_b;
+ unpack_d (&au, &a);
+ unpack_d (&bu, &b);
+
if (isnan (&a) || isnan (&b))
return 1; /* true, truth != 0 */
@@ -1247,9 +1275,13 @@ _gt_f2 (FLO_type arg_a, FLO_type arg_b)
{
fp_number_type a;
fp_number_type b;
+ FLO_union_type au, bu;
+
+ au.value = arg_a;
+ bu.value = arg_b;
- unpack_d ((FLO_union_type *) & arg_a, &a);
- unpack_d ((FLO_union_type *) & arg_b, &b);
+ unpack_d (&au, &a);
+ unpack_d (&bu, &b);
if (isnan (&a) || isnan (&b))
return -1; /* false, truth > 0 */
@@ -1264,10 +1296,14 @@ _ge_f2 (FLO_type arg_a, FLO_type arg_b)
{
fp_number_type a;
fp_number_type b;
+ FLO_union_type au, bu;
- unpack_d ((FLO_union_type *) & arg_a, &a);
- unpack_d ((FLO_union_type *) & arg_b, &b);
+ au.value = arg_a;
+ bu.value = arg_b;
+ unpack_d (&au, &a);
+ unpack_d (&bu, &b);
+
if (isnan (&a) || isnan (&b))
return -1; /* false, truth >= 0 */
return __fpcmp_parts (&a, &b) ;
@@ -1280,9 +1316,13 @@ _lt_f2 (FLO_type arg_a, FLO_type arg_b)
{
fp_number_type a;
fp_number_type b;
+ FLO_union_type au, bu;
+
+ au.value = arg_a;
+ bu.value = arg_b;
- unpack_d ((FLO_union_type *) & arg_a, &a);
- unpack_d ((FLO_union_type *) & arg_b, &b);
+ unpack_d (&au, &a);
+ unpack_d (&bu, &b);
if (isnan (&a) || isnan (&b))
return 1; /* false, truth < 0 */
@@ -1297,10 +1337,14 @@ _le_f2 (FLO_type arg_a, FLO_type arg_b)
{
fp_number_type a;
fp_number_type b;
+ FLO_union_type au, bu;
- unpack_d ((FLO_union_type *) & arg_a, &a);
- unpack_d ((FLO_union_type *) & arg_b, &b);
+ au.value = arg_a;
+ bu.value = arg_b;
+ unpack_d (&au, &a);
+ unpack_d (&bu, &b);
+
if (isnan (&a) || isnan (&b))
return 1; /* false, truth <= 0 */
@@ -1354,8 +1398,11 @@ float_to_si (FLO_type arg_a)
{
fp_number_type a;
SItype tmp;
+ FLO_union_type au;
+
+ au.value = arg_a;
+ unpack_d (&au, &a);
- unpack_d ((FLO_union_type *) & arg_a, &a);
if (iszero (&a))
return 0;
if (isnan (&a))
@@ -1385,8 +1432,11 @@ USItype
float_to_usi (FLO_type arg_a)
{
fp_number_type a;
+ FLO_union_type au;
- unpack_d ((FLO_union_type *) & arg_a, &a);
+ au.value = arg_a;
+ unpack_d (&au, &a);
+
if (iszero (&a))
return 0;
if (isnan (&a))
@@ -1415,8 +1465,11 @@ FLO_type
negate (FLO_type arg_a)
{
fp_number_type a;
+ FLO_union_type au;
+
+ au.value = arg_a;
+ unpack_d (&au, &a);
- unpack_d ((FLO_union_type *) & arg_a, &a);
flip_sign (&a);
return pack_d (&a);
}
@@ -1455,8 +1508,11 @@ DFtype
sf_to_df (SFtype arg_a)
{
fp_number_type in;
+ FLO_union_type au;
+
+ au.value = arg_a;
+ unpack_d (&au, &in);
- unpack_d ((FLO_union_type *) & arg_a, &in);
return __make_dp (in.class, in.sign, in.normal_exp,
((UDItype) in.fraction.ll) << F_D_BITOFF);
}
@@ -1489,8 +1545,10 @@ df_to_sf (DFtype arg_a)
{
fp_number_type in;
USItype sffrac;
+ FLO_union_type au;
- unpack_d ((FLO_union_type *) & arg_a, &in);
+ au.value = arg_a;
+ unpack_d (&au, &in);
sffrac = in.fraction.ll >> F_D_BITOFF;