RISC-V: Make sure stack is always aligned during adjusting stack.

	gcc/
	2018-04-20  Kito Cheng  <kito.cheng@gmail.com>
	* config/riscv/riscv.c (riscv_first_stack_step): Round up min
	step to make sure stack always aligned.

From-SVN: r259530

gcc/ChangeLog

+2018-04-20  Kito Cheng  <kito.cheng@gmail.com>
+
+	* config/riscv/riscv.c (riscv_first_stack_step): Round up min
+	step to make sure stack always aligned.
+
 2018-04-20  Carl Love  <cel@us.ibm.com>
 
         PR target/83402

gcc/config/riscv/riscv.c

@@ -3507,7 +3507,8 @@ riscv_first_stack_step (struct riscv_frame_info *frame)
   if (SMALL_OPERAND (frame->total_size))
     return frame->total_size;
 
-  HOST_WIDE_INT min_first_step = frame->total_size - frame->fp_sp_offset;
+  HOST_WIDE_INT min_first_step =
+    RISCV_STACK_ALIGN (frame->total_size - frame->fp_sp_offset);
   HOST_WIDE_INT max_first_step = IMM_REACH / 2 - PREFERRED_STACK_BOUNDARY / 8;
   HOST_WIDE_INT min_second_step = frame->total_size - max_first_step;
   gcc_assert (min_first_step <= max_first_step);