2005-09-07 Jakub Jelinek <jakub@redhat.com>
PR target/18300
* config/i386/i386.c (classify_argument): Only use different
iterators for nested loops if nested loops sharing the same
iterator would hang.
2004-11-13 Zak Kipling <zak@transversal.com>
PR target/18300
* config/i386/i386.c (classify_argument): Fix infinite loop when
passing object with 3 or more base classes by value.
--- gcc/config/i386/i386.c.jj 2005-07-21 11:01:36.000000000 +0200
+++ gcc/config/i386/i386.c 2005-09-07 14:22:19.000000000 +0200
@@ -2028,8 +2028,17 @@ classify_argument (enum machine_mode mod
{
tree bases = TYPE_BINFO_BASETYPES (type);
int n_bases = TREE_VEC_LENGTH (bases);
- int i;
-
+ int i, basenum;
+ enum x86_64_reg_class saveclasses[MAX_CLASSES];
+ bool seen[MAX_CLASSES];
+
+ /* PR target/18300: The following code mistakenly uses the same
+ iterator variable in both nested for loops. But to preserve
+ binary compatibility, do whatever this code used to do before
+ unless old GCC would hang in an infinite loop. In that case
+ use whatever GCC 4.0+ does. */
+ memset (seen, 0, sizeof (seen));
+ memcpy (saveclasses, classes, sizeof (saveclasses));
for (i = 0; i < n_bases; ++i)
{
tree binfo = TREE_VEC_ELT (bases, i);
@@ -2037,6 +2046,12 @@ classify_argument (enum machine_mode mod
int offset = tree_low_cst (BINFO_OFFSET (binfo), 0) * 8;
tree type = BINFO_TYPE (binfo);
+ if (i < MAX_CLASSES)
+ {
+ if (seen[i])
+ break;
+ seen[i] = true;
+ }
num = classify_argument (TYPE_MODE (type),
type, subclasses,
(offset + bit_offset) % 256);
@@ -2049,6 +2064,32 @@ classify_argument (enum machine_mode mod
merge_classes (subclasses[i], classes[i + pos]);
}
}
+ if (i < n_bases)
+ {
+ /* Older GCC 3.[0-4].x would hang in the above loop, so
+ don't worry about backwards compatibility and
+ just DTRT. */
+ memcpy (classes, saveclasses, sizeof (saveclasses));
+ for (basenum = 0; basenum < n_bases; ++basenum)
+ {
+ tree binfo = TREE_VEC_ELT (bases, basenum);
+ int num;
+ int offset = tree_low_cst (BINFO_OFFSET (binfo), 0) * 8;
+ tree type = BINFO_TYPE (binfo);
+
+ num = classify_argument (TYPE_MODE (type),
+ type, subclasses,
+ (offset + bit_offset) % 256);
+ if (!num)
+ return 0;
+ for (i = 0; i < num; i++)
+ {
+ int pos = (offset + (bit_offset % 64)) / 8 / 8;
+ classes[i + pos] =
+ merge_classes (subclasses[i], classes[i + pos]);
+ }
+ }
+ }
}
/* And now merge the fields of structure. */
for (field = TYPE_FIELDS (type); field; field = TREE_CHAIN (field))
@@ -2116,8 +2157,17 @@ classify_argument (enum machine_mode mod
{
tree bases = TYPE_BINFO_BASETYPES (type);
int n_bases = TREE_VEC_LENGTH (bases);
- int i;
-
+ int i, basenum;
+ enum x86_64_reg_class saveclasses[MAX_CLASSES];
+ bool seen[MAX_CLASSES];
+
+ /* PR target/18300: The following code mistakenly uses the same
+ iterator variable in both nested for loops. But to preserve
+ binary compatibility, do whatever this code used to do before
+ unless old GCC would hang in an infinite loop. In that case
+ use whatever GCC 4.0+ does. */
+ memset (seen, 0, sizeof (seen));
+ memcpy (saveclasses, classes, sizeof (saveclasses));
for (i = 0; i < n_bases; ++i)
{
tree binfo = TREE_VEC_ELT (bases, i);
@@ -2125,6 +2175,12 @@ classify_argument (enum machine_mode mod
int offset = tree_low_cst (BINFO_OFFSET (binfo), 0) * 8;
tree type = BINFO_TYPE (binfo);
+ if (i < MAX_CLASSES)
+ {
+ if (seen[i])
+ break;
+ seen[i] = true;
+ }
num = classify_argument (TYPE_MODE (type),
type, subclasses,
(offset + (bit_offset % 64)) % 256);
@@ -2137,6 +2193,32 @@ classify_argument (enum machine_mode mod
merge_classes (subclasses[i], classes[i + pos]);
}
}
+ if (i < n_bases)
+ {
+ /* Older GCC 3.[0-4].x would hang in the above loop, so
+ don't worry about backwards compatibility and
+ just DTRT. */
+ memcpy (classes, saveclasses, sizeof (saveclasses));
+ for (basenum = 0; basenum < n_bases; ++basenum)
+ {
+ tree binfo = TREE_VEC_ELT (bases, basenum);
+ int num;
+ int offset = tree_low_cst (BINFO_OFFSET (binfo), 0) * 8;
+ tree type = BINFO_TYPE (binfo);
+
+ num = classify_argument (TYPE_MODE (type),
+ type, subclasses,
+ (offset + (bit_offset % 64)) % 256);
+ if (!num)
+ return 0;
+ for (i = 0; i < num; i++)
+ {
+ int pos = (offset + (bit_offset % 64)) / 8 / 8;
+ classes[i + pos] =
+ merge_classes (subclasses[i], classes[i + pos]);
+ }
+ }
+ }
}
for (field = TYPE_FIELDS (type); field; field = TREE_CHAIN (field))
{
--- gcc/testsuite/g++.dg/other/infloop-1.C 1 Jan 1970 00:00:00 -0000
+++ gcc/testsuite/g++.dg/other/infloop-1.C 13 Nov 2004 23:09:08 -0000 1.1
@@ -0,0 +1,16 @@
+// PR 18300: This sends old compilers into an infinite loop on x86_64
+// Testcase and patch contributed by Zak Kipling <zak@transversal.com>
+
+struct base1 { };
+struct base2 { };
+struct base3 { };
+
+struct derived : base1, base2, base3 { };
+
+void foo(derived);
+
+int main()
+{
+ foo(derived());
+}
+