diff -urpN a/gcc/config/aarch64/aarch64.c b/gcc/config/aarch64/aarch64.c
--- a/gcc/config/aarch64/aarch64.c	2018-10-09 11:49:19.000000000 +0800
+++ b/gcc/config/aarch64/aarch64.c	2018-10-09 13:42:15.000000000 +0800
@@ -1619,7 +1619,7 @@ aarch64_load_symref_appropriately (rtx d
     case SYMBOL_SMALL_TLSDESC:
       {
 	machine_mode mode = GET_MODE (dest);
-	rtx x0 = gen_rtx_REG (mode, R0_REGNUM);
+	rtx x0 = gen_rtx_REG (ptr_mode, R0_REGNUM);
 	rtx tp;
 
 	gcc_assert (mode == Pmode || mode == ptr_mode);
@@ -1635,6 +1635,11 @@ aarch64_load_symref_appropriately (rtx d
 	if (mode != Pmode)
 	  tp = gen_lowpart (mode, tp);
 
+	if (mode != ptr_mode)
+	  {
+	    x0 = force_reg (mode, gen_rtx_SIGN_EXTEND (mode, x0));
+	  }
+
 	emit_insn (gen_rtx_SET (dest, gen_rtx_PLUS (mode, tp, x0)));
 	set_unique_reg_note (get_last_insn (), REG_EQUIV, imm);
 	return;