diff --git a/gcc/emit-rtl.cc b/gcc/emit-rtl.cc
index f4404d7abe33b565358b7f609a91114c75ecf4e7..15ffca2ffe986bca56c1fae9381bd33f5d6b012d 100644
--- a/gcc/emit-rtl.cc
+++ b/gcc/emit-rtl.cc
@@ -947,9 +947,11 @@ validate_subreg (machine_mode omode, machine_mode imode,
 	   && GET_MODE_INNER (omode) == GET_MODE_INNER (imode))
     ;
   /* Subregs involving floating point modes are not allowed to
-     change size.  Therefore (subreg:DI (reg:DF) 0) is fine, but
+     change size unless it's an insert into a complex mode.
+     Therefore (subreg:DI (reg:DF) 0) and (subreg:CS (reg:SF) 0) are fine, but
      (subreg:SI (reg:DF) 0) isn't.  */
-  else if (FLOAT_MODE_P (imode) || FLOAT_MODE_P (omode))
+  else if ((FLOAT_MODE_P (imode) || FLOAT_MODE_P (omode))
+	   && !COMPLEX_MODE_P (omode))
     {
       if (! (known_eq (isize, osize)
 	     /* LRA can use subreg to store a floating point value in
diff --git a/gcc/expr.cc b/gcc/expr.cc
index 5f7142b975ada2cd8b00663d35ba1e0004b8e28d..fce672c236fdbc4d40adb6e2614c234c02a61933 100644
--- a/gcc/expr.cc
+++ b/gcc/expr.cc
@@ -3740,7 +3740,17 @@ emit_move_complex_parts (rtx x, rtx y)
       && REG_P (x) && !reg_overlap_mentioned_p (x, y))
     emit_clobber (x);
 
-  write_complex_part (x, read_complex_part (y, false), false);
+  /* If we're writing the entire value using a concat into a register
+     then emit the lower part as a simple mov followed by an insert
+     into the top part.  */
+  if (GET_CODE (y) == CONCAT && !reload_completed && REG_P (x))
+    {
+      rtx val = XEXP (y, false);
+      rtx dest = lowpart_subreg (GET_MODE (val), x, GET_MODE (x));
+      emit_move_insn (dest, val);
+    }
+  else
+    write_complex_part (x, read_complex_part (y, false), false);
   write_complex_part (x, read_complex_part (y, true), true);
 
   return get_last_insn ();
diff --git a/gcc/testsuite/g++.target/aarch64/complex-init.C b/gcc/testsuite/g++.target/aarch64/complex-init.C
new file mode 100644
index 0000000000000000000000000000000000000000..497cc4bca3e2c59da95c871ceb5cc96216fc302d
--- /dev/null
+++ b/gcc/testsuite/g++.target/aarch64/complex-init.C
@@ -0,0 +1,40 @@
+/* { dg-do compile } */
+/* { dg-options "-O2" } */
+/* { dg-final { check-function-bodies "**" "" "" { target { le } } } } */
+
+/*
+** _Z1fii:
+** ...
+** 	bfi	x0, x1, 32, 32
+** 	ret
+** ...
+*/
+_Complex int f(int a, int b) {
+    _Complex int t = a + b * 1i;
+    return t;
+}
+
+/*
+** _Z2f2ii:
+** ...
+** 	bfi	x0, x1, 32, 32
+** 	ret
+** ...
+*/
+_Complex int f2(int a, int b) {
+    _Complex int t = {a, b};
+    return t;
+}
+
+/*
+** _Z12f_convolutedii:
+** ...
+** 	bfi	x0, x1, 32, 32
+** 	ret
+** ...
+*/
+_Complex int f_convoluted(int a, int b) {
+    _Complex int t = (_Complex int)a;
+    __imag__ t = b;
+    return t;
+}