diff --git a/gcc/rtl-ssa/changes.cc b/gcc/rtl-ssa/changes.cc
index e0df982880c7..8afe8ea4eb35 100644
--- a/gcc/rtl-ssa/changes.cc
+++ b/gcc/rtl-ssa/changes.cc
@@ -110,9 +110,10 @@ function_info::verify_insn_changes (array_slice<insn_change *const> changes)
 	// Make sure that the changes can be kept in their current order
 	// while honoring all of the move ranges.
 	min_insn = later_insn (min_insn, change->move_range.first);
-	while (min_insn != change->insn () && !can_insert_after (min_insn))
+	while (min_insn && min_insn != change->insn () && !can_insert_after (min_insn))
 	  min_insn = min_insn->next_nondebug_insn ();
-	if (*min_insn > *change->move_range.last)
+
+	if (!min_insn || *min_insn > *change->move_range.last)
 	  {
 	    if (dump_file && (dump_flags & TDF_DETAILS))
 	      fprintf (dump_file, "no viable insn position assignment\n");
diff --git a/gcc/testsuite/gcc.dg/torture/pr123994.c b/gcc/testsuite/gcc.dg/torture/pr123994.c
new file mode 100644
index 000000000000..3db7d85b9d4f
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/torture/pr123994.c
@@ -0,0 +1,31 @@
+/* { dg-do compile } */
+/* { dg-require-effective-target lp64 } */
+/* { dg-additional-options "-w" } */
+#include <stdint.h>
+#define BS_VEC(type, num) type __attribute__((vector_size(num * sizeof(type))))
+uint8_t backsmith_snippet_141(int16_t, uint64_t);
+int32_t backsmith_snippet_122(uint64_t BS_ARG_0, uint32_t BS_ARG_1)
+{
+    BS_ARG_0 =
+        BS_ARG_1 ? (BS_VEC(uint64_t, 16)){}[BS_ARG_0] : 4054722019416799465;
+    return BS_ARG_0;
+}
+uint16_t backsmith_pure_0(uint64_t BS_ARG_2, uint32_t BS_ARG_3)
+{
+    int64_t BS_VAR_0[6];
+    int8_t BS_VAR_3[80];
+    for (uint16_t BS_INC_0 = 0; BS_INC_0 < 8; BS_INC_0 += 1)
+    {
+        uint64_t BS_TEMP_590 = BS_INC_0;
+        BS_VAR_0[BS_INC_0] = BS_INC_0
+            ? (BS_TEMP_590 ? BS_ARG_2 >> BS_TEMP_590 : 0)
+                ?: backsmith_snippet_141(0, BS_INC_0)
+            : 0;
+        BS_VAR_3[BS_INC_0] =
+            backsmith_snippet_122(BS_VAR_0[6 ? (uint64_t)BS_INC_0 : 0] < 0,
+                                  BS_ARG_3)
+            ?: BS_ARG_3;
+    }
+    if (BS_ARG_2) BS_VAR_3[BS_ARG_3 < 80 ? BS_ARG_3 : 0] = 0;
+    return BS_VAR_3[4];
+}