[PATCH, ARM] Fix PR44557 (Thumb-1 ICE)

[Chung-Lin Tang]

There was a patch of mine here from over an year ago:
http://gcc.gnu.org/ml/gcc-patches/2011-01/msg01846.html

That old patch contained a constraint modification that was a point of
discussion at the time, but upon re-testing I found it was unneeded for
fixing the PR (don't remember why I included it)

Resubmitting the patch adapted, basically a single-liner adding
CORE_REGS to the preferred reload class under Thumb-1. Cross-tested
with no regressions under "-march=armv5te -mthumb". Okay for trunk?

Thanks,
Chung-Lin

2012-09-26  Chung-Lin Tang  <clt...@codesourcery.com>

        PR target/44557
        * config/arm/arm.c (arm_preferred_reload_class): Add CORE_REGS
        to Thumb-1 case.

        testsuite/
        PR target/44557
        * gcc.target/arm/pr44557.c: New test.

Index: config/arm/arm.c
===================================================================
--- config/arm/arm.c    (revision 191753)
+++ config/arm/arm.c    (working copy)
@@ -6254,6 +6254,7 @@ arm_preferred_reload_class (rtx x ATTRIBUTE_UNUSED
   else
     {
       if (rclass == GENERAL_REGS
+         || rclass == CORE_REGS
          || rclass == HI_REGS
          || rclass == NO_REGS
          || rclass == STACK_REG)
Index: testsuite/gcc.target/arm/pr44557.c
===================================================================
--- testsuite/gcc.target/arm/pr44557.c  (revision 0)
+++ testsuite/gcc.target/arm/pr44557.c  (revision 0)
@@ -0,0 +1,26 @@
+/* { dg-do compile } */
+/* { dg-options "-mthumb -O1 -march=armv5te -fno-omit-frame-pointer 
-fno-forward-propagate" }  */
+/* { dg-require-effective-target arm_thumb1_ok } */
+
+struct S
+{
+  short x, y;
+};
+
+void foo (struct S *p, struct S *q, char *t, int n)
+{
+  struct S *c, d;
+  int x = 1;
+
+  while (n--)
+    {
+      if (*t && p)
+      c = p;
+      q->x = d.x + c->x + c->y;
+      if (x)
+      {
+        x = 0;
+          d.x += c->x;
+          }
+    }
+}