Hi,
The problem appears in revision 201034 in version 4.9. I attached
one-line patches that fixes it. I also reported this problem
at http://gcc.gnu.org/bugzilla/show_bug.cgi?id=57811
Bootstrap and regression-tested on x86_64-linux.
In method "find_reloads()" in gcc/reload.c, the loop on line 3324 should
break immediately after "badop" is set to "1". Also, the loop on line 4641
should break after "ok" is set to "0".
2013-07-22 Chang <pcha...@cs.wisc.edu>
* reload.c (find_reloads): Exit loop once we find this operand
cannot be reloaded somehow for this alternative.
* reload.c (find_reloads): Exit loop once we find a
hard register.
Index: gcc/reload.c
===================================================================
--- gcc/reload.c (revision 201034)
+++ gcc/reload.c (working copy)
@@ -3324,7 +3324,10 @@
for (j = 0; j < i; j++)
if (this_alternative_matches[j]
== this_alternative_matches[i])
- badop = 1;
+ {
+ badop = 1;
+ break;
+ }
break;
case 'p':
Index: gcc/reload.c
===================================================================
--- gcc/reload.c (revision 201034)
+++ gcc/reload.c (working copy)
@@ -4640,7 +4640,10 @@
for (nri = 1; nri < nr; nri ++)
if (! TEST_HARD_REG_BIT (reg_class_contents[rld[i].rclass], regno
+ nri))
- ok = 0;
+ {
+ ok = 0;
+ break;
+ }
if (ok)
rld[i].reg_rtx = dest;
-Chang
Index: gcc/reload.c
===================================================================
--- gcc/reload.c (revision 201034)
+++ gcc/reload.c (working copy)
@@ -3324,7 +3324,10 @@
for (j = 0; j < i; j++)
if (this_alternative_matches[j]
== this_alternative_matches[i])
- badop = 1;
+ {
+ badop = 1;
+ break;
+ }
break;
case 'p':Index: gcc/reload.c
===================================================================
--- gcc/reload.c (revision 201034)
+++ gcc/reload.c (working copy)
@@ -4640,7 +4640,10 @@
for (nri = 1; nri < nr; nri ++)
if (! TEST_HARD_REG_BIT (reg_class_contents[rld[i].rclass], regno
+ nri))
- ok = 0;
+ {
+ ok = 0;
+ break;
+ }
if (ok)
rld[i].reg_rtx = dest;
