diff --git a/gcc/df-problems.cc b/gcc/df-problems.cc
index f32185b3eac..90753793098 100644
--- a/gcc/df-problems.cc
+++ b/gcc/df-problems.cc
@@ -3893,9 +3893,11 @@ df_simulate_defs (rtx_insn *insn, bitmap live)
     {
       unsigned int dregno = DF_REF_REGNO (def);
 
-      /* If the def is to only part of the reg, it does
-	 not kill the other defs that reach here.  */
-      if (!(DF_REF_FLAGS (def) & (DF_REF_PARTIAL | DF_REF_CONDITIONAL)))
+      /* If the def is to only part of the reg, model it as a RMW operation
+	 by marking it live.  It only kills the reg if it is a complete def.  */
+      if (DF_REF_FLAGS (def) & (DF_REF_PARTIAL | DF_REF_CONDITIONAL))
+	bitmap_set_bit (live, dregno);
+      else
 	bitmap_clear_bit (live, dregno);
     }
 }
diff --git a/gcc/testsuite/gcc.target/aarch64/torture/pr116564.c b/gcc/testsuite/gcc.target/aarch64/torture/pr116564.c
new file mode 100644
index 00000000000..d471e097294
--- /dev/null
+++ b/gcc/testsuite/gcc.target/aarch64/torture/pr116564.c
@@ -0,0 +1,11 @@
+/* { dg-do compile } */
+/* { dg-options "" } */
+#include <arm_neon.h>
+void test()
+{
+  for (int L = 0; L < 4; ++L) {
+    float64_t ResData[1 * 2];
+    float64x1x2_t Src1;
+    vst2_f64(ResData, Src1);
+  }
+}