[PATCH][4.9/5 Backport] PR rtl-optimization/67037 Use copy_rtx when necessary

[Grazvydas Ignotas]

Hi,

This is the 4.9 and GCC 5 backport of patch from PR67037 that's already in 
trunk.
I've build it on 4.9 and confirmed that it works.

Grazvydas

Backport from mainline
2015-09-30  Bernd Edlinger  <bernd.edlin...@hotmail.de>

        PR rtl-optimization/67037
        * lra-constraints.c (process_addr_reg): Use copy_rtx when necessary.

testsuite:
2015-09-30  Bernd Edlinger  <bernd.edlin...@hotmail.de>

        PR rtl-optimization/67037
        * gcc.c-torture/execute/pr67037.c: New test.
---
 gcc/lra-constraints.c                         |  2 +-
 gcc/testsuite/gcc.c-torture/execute/pr67037.c | 49 +++++++++++++++++++++++++++
 2 files changed, 50 insertions(+), 1 deletion(-)
 create mode 100644 gcc/testsuite/gcc.c-torture/execute/pr67037.c

diff --git a/gcc/lra-constraints.c b/gcc/lra-constraints.c
index ae8f3cd..919b127 100644
--- a/gcc/lra-constraints.c
+++ b/gcc/lra-constraints.c
@@ -1203,7 +1203,7 @@ process_addr_reg (rtx *loc, rtx *before, rtx *after, enum 
reg_class cl)
   if (after != NULL)
     {
       start_sequence ();
-      lra_emit_move (reg, new_reg);
+      lra_emit_move (before_p ? copy_rtx (reg) : reg, new_reg);
       emit_insn (*after);
       *after = get_insns ();
       end_sequence ();
diff --git a/gcc/testsuite/gcc.c-torture/execute/pr67037.c 
b/gcc/testsuite/gcc.c-torture/execute/pr67037.c
new file mode 100644
index 0000000..3119d32
--- /dev/null
+++ b/gcc/testsuite/gcc.c-torture/execute/pr67037.c
@@ -0,0 +1,49 @@
+long (*extfunc)();
+
+static inline void lstrcpynW( short *d, const short *s, int n )
+{
+    unsigned int count = n;
+
+    while ((count > 1) && *s)
+    {
+        count--;
+        *d++ = *s++;
+    }
+    if (count) *d = 0;
+}
+
+int __attribute__((noinline,noclone))
+badfunc(int u0, int u1, int u2, int u3,
+  short *fsname, unsigned int fsname_len)
+{
+    static const short ntfsW[] = {'N','T','F','S',0};
+    char superblock[2048+3300];
+    int ret = 0;
+    short *p;
+
+    if (extfunc())
+        return 0;
+    p = (void *)extfunc();
+    if (p != 0)
+        goto done;
+
+    extfunc(superblock);
+
+    lstrcpynW(fsname, ntfsW, fsname_len);
+
+    ret = 1;
+done:
+    return ret;
+}
+
+static long f()
+{
+    return 0;
+}
+
+int main()
+{
+    short buf[6];
+    extfunc = f;
+    return !badfunc(0, 0, 0, 0, buf, 6);
+}
-- 
1.9.1