[PATCH] Handle VEC_SERIES with both constant args in simplify_binary_operation

[Jakub Jelinek <jakub@redhat.com>]

Hi!

I've noticed that if we construct a VEC_SERIES and later propagate
constants into both arguments (could happen e.g. in DEBUG_INSNs, or
during combine etc.) we don't simplify that.

The following patch adds that, ok for trunk if it passes bootstrap/regtest?

Or should it go into simplify_constant_binary_operation instead?
In there it would better match the function name, on the other side
it would slow down the function for quite a marginal case, because it
doesn't have a big switch on code, but instead handles just a few cases
if constant operand kinds vs. the mode.

2017-11-22  Jakub Jelinek  <jakub@redhat.com>

	* simplify-rtx.c (simplify_binary_operation_1) <case VEC_SERIES>:
	Handle the case where both arguments are using gen_const_vec_series.

--- gcc/simplify-rtx.c.jj	2017-11-20 11:02:42.000000000 +0100
+++ gcc/simplify-rtx.c	2017-11-22 12:30:46.808056343 +0100
@@ -3566,6 +3566,8 @@ simplify_binary_operation_1 (enum rtx_co
     case VEC_SERIES:
       if (op1 == CONST0_RTX (GET_MODE_INNER (mode)))
 	return gen_vec_duplicate (mode, op0);
+      if (CONSTANT_P (op0) && CONSTANT_P (op1))
+	return gen_const_vec_series (mode, op0, op1);
       return 0;
 
     case VEC_SELECT:
@@ -6652,6 +6654,9 @@ test_vector_ops_series (machine_mode mod
   ASSERT_RTX_EQ (series_r_1,
 		 simplify_binary_operation (MINUS, mode, duplicate,
 					    series_0_m1));
+  ASSERT_RTX_EQ (series_0_m1,
+		 simplify_binary_operation (VEC_SERIES, mode, const0_rtx,
+					    constm1_rtx));
 }
 
 /* Verify some simplifications involving vectors.  */

	Jakub