re PR tree-optimization/84841 (ICE: tree check: expected ssa_name, have real_cst…

re PR tree-optimization/84841 (ICE: tree check: expected ssa_name, have real_cst in rewrite_expr_tree_parallel, at tree-ssa-reassoc.c:4624)

	PR tree-optimization/84841
	* tree-ssa-reassoc.c (INTEGER_CONST_TYPE): Change to 1 << 4 from
	1 << 3.
	(FLOAT_ONE_CONST_TYPE): Define.
	(constant_type): Return FLOAT_ONE_CONST_TYPE for -1.0 and 1.0.
	(sort_by_operand_rank): Put entries with higher constant_type last
	rather than first to match comments.

	* gcc.dg/pr84841.c: New test.

From-SVN: r258586

gcc/ChangeLog

+2018-03-16  Jakub Jelinek  <jakub@redhat.com>
+
+	PR tree-optimization/84841
+	* tree-ssa-reassoc.c (INTEGER_CONST_TYPE): Change to 1 << 4 from
+	1 << 3.
+	(FLOAT_ONE_CONST_TYPE): Define.
+	(constant_type): Return FLOAT_ONE_CONST_TYPE for -1.0 and 1.0.
+	(sort_by_operand_rank): Put entries with higher constant_type last
+	rather than first to match comments.
+
 2018-03-15  Sandra Loosemore  <sandra@codesourcery.com>
 
 	* config/nios2/nios2.md (movsi_internal): Fix thinko in 

gcc/testsuite/ChangeLog

 2018-03-16  Jakub Jelinek  <jakub@redhat.com>
 
+	PR tree-optimization/84841
+	* gcc.dg/pr84841.c: New test.
+
 	PR c++/84874
 	* g++.dg/cpp2a/desig7.C: New test.
 

gcc/testsuite/gcc.dg/pr84841.c

+/* PR tree-optimization/84841 */
+/* { dg-do compile } */
+/* { dg-options "-O2 -fassociative-math -frounding-math -fno-signed-zeros -fno-trapping-math -fno-tree-forwprop" } */
+
+double
+foo (double x)
+{
+  return -x * 0.1 * 0.1;
+}

gcc/tree-ssa-reassoc.c

@@ -470,7 +470,8 @@ get_rank (tree e)
 
 /* We want integer ones to end up last no matter what, since they are
    the ones we can do the most with.  */
-#define INTEGER_CONST_TYPE 1 << 3
+#define INTEGER_CONST_TYPE 1 << 4
+#define FLOAT_ONE_CONST_TYPE 1 << 3
 #define FLOAT_CONST_TYPE 1 << 2
 #define OTHER_CONST_TYPE 1 << 1
 
@@ -482,7 +483,14 @@ constant_type (tree t)
   if (INTEGRAL_TYPE_P (TREE_TYPE (t)))
     return INTEGER_CONST_TYPE;
   else if (SCALAR_FLOAT_TYPE_P (TREE_TYPE (t)))
-    return FLOAT_CONST_TYPE;
+    {
+      /* Sort -1.0 and 1.0 constants last, while in some cases
+	 const_binop can't optimize some inexact operations, multiplication
+	 by -1.0 or 1.0 can be always merged with others.  */
+      if (real_onep (t) || real_minus_onep (t))
+	return FLOAT_ONE_CONST_TYPE;
+      return FLOAT_CONST_TYPE;
+    }
   else
     return OTHER_CONST_TYPE;
 }
@@ -504,7 +512,7 @@ sort_by_operand_rank (const void *pa, const void *pb)
   if (oea->rank == 0)
     {
       if (constant_type (oeb->op) != constant_type (oea->op))
-	return constant_type (oeb->op) - constant_type (oea->op);
+	return constant_type (oea->op) - constant_type (oeb->op);
       else
 	/* To make sorting result stable, we use unique IDs to determine
 	   order.  */