diff --git a/gcc/config/or1k/or1k.cc b/gcc/config/or1k/or1k.cc
index 17240e3ee48..66fd784f8b9 100644
--- a/gcc/config/or1k/or1k.cc
+++ b/gcc/config/or1k/or1k.cc
@@ -1389,10 +1389,11 @@ or1k_trampoline_init (rtx m_tramp, tree fndecl, rtx chain)
 static bool
 or1k_hard_regno_mode_ok (unsigned int regno, machine_mode mode)
 {
-  /* For OpenRISC, GENERAL_REGS can hold anything, while
-     FLAG_REGS are really single bits within SP[SR].  */
+  /* For OpenRISC, GENERAL_REGS can hold anything, while FLAG_REGS are
+     really single bits within SP[SR].  Also allow condition flag register
+     in SImode to match or1k_can_change_mode_class.  */
   if (REGNO_REG_CLASS (regno) == FLAG_REGS)
-    return mode == BImode;
+    return mode == BImode || mode == SImode;
   return true;
 }
 
diff --git a/gcc/testsuite/gcc.target/or1k/pr125155.c b/gcc/testsuite/gcc.target/or1k/pr125155.c
new file mode 100644
index 00000000000..8ca95475b66
--- /dev/null
+++ b/gcc/testsuite/gcc.target/or1k/pr125155.c
@@ -0,0 +1,14 @@
+/* { dg-do compile } */
+/* { dg-options "-O2" } */
+
+int __pthread_keys_0_0;
+int
+___pthread_key_delete (void)
+{
+  int result = 22;
+  int __atg3_old = 0;
+  if (__atomic_compare_exchange_n (&__pthread_keys_0_0, &__atg3_old,
+				   0, 0, 2, 0))
+    result = 0;
+  return result;
+}