xtensa: Fix out-of-bounds array access in the movdi pattern

The following new warnings were introduced in the commit
4f3f0296acbb ("xtensa: Prepare the transition from Reload to LRA"):

gcc/config/xtensa/xtensa.md:945:26: error: array subscript 3 is above
	array bounds of 'rtx_def* [2]' [-Werror=array-bounds]
  945 |           emit_move_insn (operands[2], operands[3]);
gcc/config/xtensa/xtensa.md:945:26: error: array subscript 2 is above
	array bounds of 'rtx_def* [2]' [-Werror=array-bounds]
  945 |           emit_move_insn (operands[2], operands[3]);

From gcc/insn-emit.cc (generated by building):

> /* ../../gcc/config/xtensa/xtensa.md:932 */
> rtx
> gen_movdi (rtx operand0,
> 	rtx operand1)
> {
>   rtx_insn *_val = 0;
>   start_sequence ();
>   {
>     rtx operands[2];					// only 2 elements
>     operands[0] = operand0;
>     operands[1] = operand1;
> #define FAIL return (end_sequence (), _val)
> #define DONE return (_val = get_insns (), end_sequence (), _val)
> #line 936 "../../gcc/config/xtensa/xtensa.md"
> {
>   if (CONSTANT_P (operands[1]))
>     {
>       /* Split in halves if 64-bit Const-to-Reg moves
> 	 because of offering further optimization opportunities.  */
>       if (register_operand (operands[0], DImode))
> 	{
> 	  xtensa_split_DI_reg_imm (operands);		// out-of-bounds!
> 	  emit_move_insn (operands[0], operands[1]);
> 	  emit_move_insn (operands[2], operands[3]);	// out-of-bounds!
> 	  DONE;
> 	}

gcc/ChangeLog:

	* config/xtensa/xtensa.md (movdi):
	Copy operands[0...1] to ops[0...3] and then use the latter before
	calling xtensa_split_DI_reg_imm() and emitting insns.

diff --git a/gcc/config/xtensa/xtensa.md b/gcc/config/xtensa/xtensa.md
index 2e7f76ada5c1df4f18a339deee45a416d7b46d7c..de9bcbf24f7ec30cebf8006db39c8e028bb8583d 100644 (file)
--- a/gcc/config/xtensa/xtensa.md
+++ b/gcc/config/xtensa/xtensa.md
@@ -940,9 +940,10 @@
         because of offering further optimization opportunities.  */
       if (register_operand (operands[0], DImode))
        {
-         xtensa_split_DI_reg_imm (operands);
-         emit_move_insn (operands[0], operands[1]);
-         emit_move_insn (operands[2], operands[3]);
+         rtx ops[4] = { operands[0], operands[1] };
+         xtensa_split_DI_reg_imm (ops);
+         emit_move_insn (ops[0], ops[1]);
+         emit_move_insn (ops[2], ops[3]);
          DONE;
        }