[PATCH] Allow useless type changes between vectype of builtin arguments (PR tree-optimization/91723)

[Jakub Jelinek]

Hi!

This testcase used to be vectorized before r260348, but isn't any longer.
The problem is that while we check with types_compatible_p:
      /* We can only handle calls with arguments of the same type.  */
      if (rhs_type
          && !types_compatible_p (rhs_type, TREE_TYPE (op)))
we required pointer equality for the corresponding vectypes, which isn't
true on the testcase, where two arguments are const float and have const
vector of float vectype, while the last one is float and has vector of float
vectype.

Fixed thusly, bootstrapped/regtested on x86_64-linux and i686-linux, ok for
trunk and 9.3 after a while?

2019-09-11  Jakub Jelinek  <jakub@redhat.com>

	PR tree-optimization/91723
	* tree-vect-stmts.c (vectorizable_call): Use types_compatible_p check
	instead of pointer equality when checking if argument vectypes are
	the same.

	* gcc.dg/vect/vect-fma-3.c: New test.

--- gcc/tree-vect-stmts.c.jj	2019-08-27 23:01:31.000000000 +0200
+++ gcc/tree-vect-stmts.c	2019-09-10 20:28:18.646389500 +0200
@@ -3308,7 +3308,7 @@ vectorizable_call (stmt_vec_info stmt_in
       if (!vectype_in)
 	vectype_in = vectypes[i];
       else if (vectypes[i]
-	       && vectypes[i] != vectype_in)
+	       && !types_compatible_p (vectypes[i], vectype_in))
 	{
 	  if (dump_enabled_p ())
 	    dump_printf_loc (MSG_MISSED_OPTIMIZATION, vect_location,
--- gcc/testsuite/gcc.dg/vect/vect-fma-3.c.jj	2019-09-10 20:39:57.219889700 +0200
+++ gcc/testsuite/gcc.dg/vect/vect-fma-3.c	2019-09-10 20:44:11.297055814 +0200
@@ -0,0 +1,17 @@
+/* PR tree-optimization/91723 */
+/* { dg-do compile { target { scalar_all_fma || { i?86-*-* x86_64-*-* } } } } */
+/* { dg-additional-options "-mfma" { target { i?86-*-* x86_64-*-* } } } */
+
+void
+foo (double *restrict r, const double *restrict a,
+     const double *restrict b, const double *restrict c)
+{
+  for (int i = 0; i < 1024; i++)
+    {
+      double x = __builtin_fma (a[i], b[i], c[i]);
+      x = __builtin_fma (a[i], b[i], x);
+      r[i] = x;
+    }
+}
+
+/* { dg-final { scan-tree-dump-times "LOOP VECTORIZED" 1 "vect" { target vect_double } } } */

	Jakub