Share code from fold_array_ctor_reference with fold.

        * gimple-fold.c (fold_array_ctor_reference): Move searching code to:
        * fold-const.c (get_array_ctor_element_at_index): New.
        (fold): Remove binary-search through CONSTRUCTOR, call previous.

        * fold-const.h (get_array_ctor_element_at_index): New.

From-SVN: r229605

gcc/ChangeLog

+2015-10-30  Alan Lawrence  <alan.lawrence@arm.com>
+
+	* gimple-fold.c (fold_array_ctor_reference): Move searching code to:
+	* fold-const.c (get_array_ctor_element_at_index): New.
+	(fold): Remove binary-search through CONSTRUCTOR, call previous.
+
+	* fold-const.h (get_array_ctor_element_at_index): New.
+
 2015-10-30  Evgeny Stupachenko  <evstupac@gmail.com>
 
 	* Makefile.in (OBJS): Add multiple_target.o.

gcc/fold-const.c

@@ -11845,6 +11845,73 @@ fold_ternary_loc (location_t loc, enum tree_code code, tree type,
     } /* switch (code) */
 }
 
+/* Gets the element ACCESS_INDEX from CTOR, which must be a CONSTRUCTOR
+   of an array (or vector).  */
+
+tree
+get_array_ctor_element_at_index (tree ctor, offset_int access_index)
+{
+  tree index_type = NULL_TREE;
+  offset_int low_bound = 0;
+
+  if (TREE_CODE (TREE_TYPE (ctor)) == ARRAY_TYPE)
+  {
+    tree domain_type = TYPE_DOMAIN (TREE_TYPE (ctor));
+    if (domain_type && TYPE_MIN_VALUE (domain_type))
+    {
+      /* Static constructors for variably sized objects makes no sense.  */
+      gcc_assert (TREE_CODE (TYPE_MIN_VALUE (domain_type)) == INTEGER_CST);
+      index_type = TREE_TYPE (TYPE_MIN_VALUE (domain_type));
+      low_bound = wi::to_offset (TYPE_MIN_VALUE (domain_type));
+    }
+  }
+
+  if (index_type)
+    access_index = wi::ext (access_index, TYPE_PRECISION (index_type),
+			    TYPE_SIGN (index_type));
+
+  offset_int index = low_bound - 1;
+  if (index_type)
+    index = wi::ext (index, TYPE_PRECISION (index_type),
+		     TYPE_SIGN (index_type));
+
+  offset_int max_index;
+  unsigned HOST_WIDE_INT cnt;
+  tree cfield, cval;
+
+  FOR_EACH_CONSTRUCTOR_ELT (CONSTRUCTOR_ELTS (ctor), cnt, cfield, cval)
+  {
+    /* Array constructor might explicitely set index, or specify range
+     * or leave index NULL meaning that it is next index after previous
+     * one.  */
+    if (cfield)
+    {
+      if (TREE_CODE (cfield) == INTEGER_CST)
+	max_index = index = wi::to_offset (cfield);
+      else
+      {
+	gcc_assert (TREE_CODE (cfield) == RANGE_EXPR);
+	index = wi::to_offset (TREE_OPERAND (cfield, 0));
+	max_index = wi::to_offset (TREE_OPERAND (cfield, 1));
+      }
+    }
+    else
+    {
+      index += 1;
+      if (index_type)
+	index = wi::ext (index, TYPE_PRECISION (index_type),
+			 TYPE_SIGN (index_type));
+	max_index = index;
+    }
+
+    /* Do we have match?  */
+    if (wi::cmpu (access_index, index) >= 0
+	&& wi::cmpu (access_index, max_index) <= 0)
+      return cval;
+  }
+  return NULL_TREE;
+}
+
 /* Perform constant folding and related simplification of EXPR.
    The related simplifications include x*1 => x, x*0 => 0, etc.,
    and application of the associative law.
@@ -11921,31 +11988,10 @@ fold (tree expr)
 	    && TREE_CODE (op0) == CONSTRUCTOR
 	    && ! type_contains_placeholder_p (TREE_TYPE (op0)))
 	  {
-	    vec<constructor_elt, va_gc> *elts = CONSTRUCTOR_ELTS (op0);
-	    unsigned HOST_WIDE_INT end = vec_safe_length (elts);
-	    unsigned HOST_WIDE_INT begin = 0;
-
-	    /* Find a matching index by means of a binary search.  */
-	    while (begin != end)
-	      {
-		unsigned HOST_WIDE_INT middle = (begin + end) / 2;
-		tree index = (*elts)[middle].index;
-
-		if (TREE_CODE (index) == INTEGER_CST
-		    && tree_int_cst_lt (index, op1))
-		  begin = middle + 1;
-		else if (TREE_CODE (index) == INTEGER_CST
-			 && tree_int_cst_lt (op1, index))
-		  end = middle;
-		else if (TREE_CODE (index) == RANGE_EXPR
-			 && tree_int_cst_lt (TREE_OPERAND (index, 1), op1))
-		  begin = middle + 1;
-		else if (TREE_CODE (index) == RANGE_EXPR
-			 && tree_int_cst_lt (op1, TREE_OPERAND (index, 0)))
-		  end = middle;
-		else
-		  return (*elts)[middle].value;
-	      }
+	    tree val = get_array_ctor_element_at_index (op0,
+							wi::to_offset (op1));
+	    if (val)
+	      return val;
 	  }
 
 	return t;

gcc/fold-const.h

@@ -73,6 +73,7 @@ extern tree fold_build_call_array_loc (location_t, tree, tree, int, tree *);
 #define fold_build_call_array_initializer(T1,T2,N,T4)\
    fold_build_call_array_initializer_loc (UNKNOWN_LOCATION, T1, T2, N, T4)
 extern tree fold_build_call_array_initializer_loc (location_t, tree, tree, int, tree *);
+extern tree get_array_ctor_element_at_index (tree, offset_int);
 extern bool fold_convertible_p (const_tree, const_tree);
 #define fold_convert(T1,T2)\
    fold_convert_loc (UNKNOWN_LOCATION, T1, T2)

gcc/gimple-fold.c

@@ -5301,13 +5301,10 @@ fold_array_ctor_reference (tree type, tree ctor,
 			   unsigned HOST_WIDE_INT size,
 			   tree from_decl)
 {
-  unsigned HOST_WIDE_INT cnt;
-  tree cfield, cval;
   offset_int low_bound;
   offset_int elt_size;
-  offset_int index, max_index;
   offset_int access_index;
-  tree domain_type = NULL_TREE, index_type = NULL_TREE;
+  tree domain_type = NULL_TREE;
   HOST_WIDE_INT inner_offset;
 
   /* Compute low bound and elt size.  */
@@ -5317,7 +5314,6 @@ fold_array_ctor_reference (tree type, tree ctor,
     {
       /* Static constructors for variably sized objects makes no sense.  */
       gcc_assert (TREE_CODE (TYPE_MIN_VALUE (domain_type)) == INTEGER_CST);
-      index_type = TREE_TYPE (TYPE_MIN_VALUE (domain_type));
       low_bound = wi::to_offset (TYPE_MIN_VALUE (domain_type));
     }
   else
@@ -5339,9 +5335,6 @@ fold_array_ctor_reference (tree type, tree ctor,
   access_index = wi::udiv_trunc (offset_int (offset / BITS_PER_UNIT),
 				 elt_size);
   access_index += low_bound;
-  if (index_type)
-    access_index = wi::ext (access_index, TYPE_PRECISION (index_type),
-			    TYPE_SIGN (index_type));
 
   /* And offset within the access.  */
   inner_offset = offset % (elt_size.to_uhwi () * BITS_PER_UNIT);
@@ -5350,43 +5343,9 @@ fold_array_ctor_reference (tree type, tree ctor,
      care to fold accesses spanning multiple array indexes.  */
   if (inner_offset + size > elt_size.to_uhwi () * BITS_PER_UNIT)
     return NULL_TREE;
+  if (tree val = get_array_ctor_element_at_index (ctor, access_index))
+    return fold_ctor_reference (type, val, inner_offset, size, from_decl);
 
-  index = low_bound - 1;
-  if (index_type)
-    index = wi::ext (index, TYPE_PRECISION (index_type),
-		     TYPE_SIGN (index_type));
-
-  FOR_EACH_CONSTRUCTOR_ELT (CONSTRUCTOR_ELTS (ctor), cnt, cfield, cval)
-    {
-      /* Array constructor might explicitely set index, or specify range
-	 or leave index NULL meaning that it is next index after previous
-	 one.  */
-      if (cfield)
-	{
-	  if (TREE_CODE (cfield) == INTEGER_CST)
-	    max_index = index = wi::to_offset (cfield);
-	  else
-	    {
-	      gcc_assert (TREE_CODE (cfield) == RANGE_EXPR);
-	      index = wi::to_offset (TREE_OPERAND (cfield, 0));
-	      max_index = wi::to_offset (TREE_OPERAND (cfield, 1));
-	    }
-	}
-      else
-	{
-	  index += 1;
-	  if (index_type)
-	    index = wi::ext (index, TYPE_PRECISION (index_type),
-			     TYPE_SIGN (index_type));
-	  max_index = index;
-	}
-
-      /* Do we have match?  */
-      if (wi::cmpu (access_index, index) >= 0
-	  && wi::cmpu (access_index, max_index) <= 0)
-	return fold_ctor_reference (type, cval, inner_offset, size,
-				    from_decl);
-    }
   /* When memory is not explicitely mentioned in constructor,
      it is 0 (or out of range).  */
   return build_zero_cst (type);