[PATCH] Fix fold-const BIT_FIELD_REF folding with 1 elt vectors (PR tree-optimization/85467)

[Jakub Jelinek]

Hi!

This PR is the fold-const.c counterpart of the match.pd PR85195,
we first check if the result type is either the element type or vector type
with the same element type, and then for extraction of a single element
simply assume that the result must be the element type; it could be single
element vector with that element type too though.

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

2018-04-19  Jakub Jelinek  <jakub@redhat.com>

	PR tree-optimization/85467
	* fold-const.c (fold_ternary_loc) <case BIT_FIELD_REF>: Use
	VECTOR_TYPE_P macro.  If type is vector type, VIEW_CONVERT_EXPR the
	VECTOR_CST element to type.

	* gcc.dg/pr85467.c: New test.

--- gcc/fold-const.c.jj	2018-04-11 12:20:53.000000000 +0200
+++ gcc/fold-const.c	2018-04-19 14:34:30.410710684 +0200
@@ -11631,7 +11631,7 @@ fold_ternary_loc (location_t loc, enum t
     case BIT_FIELD_REF:
       if (TREE_CODE (arg0) == VECTOR_CST
 	  && (type == TREE_TYPE (TREE_TYPE (arg0))
-	      || (TREE_CODE (type) == VECTOR_TYPE
+	      || (VECTOR_TYPE_P (type)
 		  && TREE_TYPE (type) == TREE_TYPE (TREE_TYPE (arg0))))
 	  && tree_fits_uhwi_p (op1)
 	  && tree_fits_uhwi_p (op2))
@@ -11653,7 +11653,12 @@ fold_ternary_loc (location_t loc, enum t
 	      if (TREE_CODE (arg0) == VECTOR_CST)
 		{
 		  if (n == 1)
-		    return VECTOR_CST_ELT (arg0, idx);
+		    {
+		      tem = VECTOR_CST_ELT (arg0, idx);
+		      if (VECTOR_TYPE_P (type))
+			tem = fold_build1 (VIEW_CONVERT_EXPR, type, tem);
+		      return tem;
+		    }
 
 		  tree_vector_builder vals (type, n, 1);
 		  for (unsigned i = 0; i < n; ++i)
--- gcc/testsuite/gcc.dg/pr85467.c.jj	2018-04-19 14:52:53.629273520 +0200
+++ gcc/testsuite/gcc.dg/pr85467.c	2018-04-19 14:51:57.348243306 +0200
@@ -0,0 +1,30 @@
+/* PR tree-optimization/85467 */
+/* { dg-do compile } */
+/* { dg-options "-O2 -fno-tree-ccp --param=sccvn-max-scc-size=10" } */
+
+#define TEST(N, T) \
+typedef T V##N __attribute__ ((__vector_size__ (sizeof (T))));	\
+								\
+V##N								\
+bar##N (V##N u, V##N v)						\
+{								\
+  do								\
+    v *= (T)((V##N){}[0] ? u[v[0]] : 0);			\
+  while ((V##N){}[0]);						\
+  return v;							\
+}								\
+								\
+void								\
+foo##N (void)							\
+{								\
+  bar##N ((V##N){}, (V##N){});					\
+}
+
+TEST (1, char)
+TEST (2, short)
+TEST (3, int)
+TEST (4, long)
+TEST (5, long long)
+#ifdef __SIZEOF_INT128__
+TEST (6, __int128)
+#endif

	Jakub