fold-const.c (fold <PLUS_EXPR>): Transform x+x into x*2.0.

	* fold-const.c (fold <PLUS_EXPR>): Transform x+x into x*2.0.
	Optimize x*c+x and x+x*c into x*(c+1) and x*c1+x*c2 into x*(c1+c2)
	for floating point expressions with -ffast-math.
	(fold <MULT_EXPR>): Don't transform x*2.0 into x+x.
	* expmed.c (expand_mult): Wrap long line.  Expand x*2.0 as x+x.

	* gcc.dg/20030804-1.c: New test case.

From-SVN: r70158

gcc/ChangeLog

 2003-08-04  Roger Sayle  <roger@eyesopen.com>
 
+	* fold-const.c (fold <PLUS_EXPR>): Transform x+x into x*2.0.
+	Optimize x*c+x and x+x*c into x*(c+1) and x*c1+x*c2 into x*(c1+c2)
+	for floating point expressions with -ffast-math.
+	(fold <MULT_EXPR>): Don't transform x*2.0 into x+x.
+	* expmed.c (expand_mult): Wrap long line.  Expand x*2.0 as x+x.
+
+2003-08-04  Roger Sayle  <roger@eyesopen.com>
+
 	* c-common.c (flag_noniso_default_format_attributes): Delete.
 	(built_in_attribute): Don't define/undefine DEF_FN_ATTR.
 	(c_attrs_initialized): Delete.

gcc/expmed.c

@@ -2300,7 +2300,8 @@ synth_mult (struct algorithm *alg_out, unsigned HOST_WIDE_INT t,
    you should swap the two operands if OP0 would be constant.  */
 
 rtx
-expand_mult (enum machine_mode mode, rtx op0, rtx op1, rtx target, int unsignedp)
+expand_mult (enum machine_mode mode, rtx op0, rtx op1, rtx target,
+	     int unsignedp)
 {
   rtx const_op1 = op1;
 
@@ -2514,6 +2515,28 @@ expand_mult (enum machine_mode mode, rtx op0, rtx op1, rtx target, int unsignedp
 	}
     }
 
+  if (GET_CODE (op0) == CONST_DOUBLE)
+    {
+      rtx temp = op0;
+      op0 = op1;
+      op1 = temp;
+    }
+
+  /* Expand x*2.0 as x+x.  */
+  if (GET_CODE (op1) == CONST_DOUBLE
+      && GET_MODE_CLASS (mode) == MODE_FLOAT)
+    {
+      REAL_VALUE_TYPE d;
+      REAL_VALUE_FROM_CONST_DOUBLE (d, op1);
+
+      if (REAL_VALUES_EQUAL (d, dconst2))
+	{
+	  op0 = force_reg (GET_MODE (op0), op0);
+	  return expand_binop (mode, add_optab, op0, op0,
+			       target, unsignedp, OPTAB_LIB_WIDEN);
+	}
+    }
+
   /* This used to use umul_optab if unsigned, but for non-widening multiply
      there is no difference between signed and unsigned.  */
   op0 = expand_binop (mode,

gcc/fold-const.c

@@ -5659,14 +5659,72 @@ fold (tree expr)
 				    same));
 	    }
 	}
+      else
+	{
+	  /* See if ARG1 is zero and X + ARG1 reduces to X.  */
+	  if (fold_real_zero_addition_p (TREE_TYPE (arg0), arg1, 0))
+	    return non_lvalue (convert (type, arg0));
 
-      /* See if ARG1 is zero and X + ARG1 reduces to X.  */
-      else if (fold_real_zero_addition_p (TREE_TYPE (arg0), arg1, 0))
-	return non_lvalue (convert (type, arg0));
+	  /* Likewise if the operands are reversed.  */
+	  if (fold_real_zero_addition_p (TREE_TYPE (arg1), arg0, 0))
+	    return non_lvalue (convert (type, arg1));
 
-      /* Likewise if the operands are reversed.  */
-      else if (fold_real_zero_addition_p (TREE_TYPE (arg1), arg0, 0))
-	return non_lvalue (convert (type, arg1));
+	  /* Convert x+x into x*2.0.  */
+	  if (operand_equal_p (arg0, arg1, 0))
+	    return fold (build (MULT_EXPR, type, arg0,
+				build_real (type, dconst2)));
+
+	  /* Convert x*c+x into x*(c+1).  */
+	  if (flag_unsafe_math_optimizations
+	      && TREE_CODE (arg0) == MULT_EXPR
+	      && TREE_CODE (TREE_OPERAND (arg0, 1)) == REAL_CST
+	      && ! TREE_CONSTANT_OVERFLOW (TREE_OPERAND (arg0, 1))
+	      && operand_equal_p (TREE_OPERAND (arg0, 0), arg1, 0))
+	    {
+	      REAL_VALUE_TYPE c;
+
+	      c = TREE_REAL_CST (TREE_OPERAND (arg0, 1));
+	      real_arithmetic (&c, PLUS_EXPR, &c, &dconst1);
+	      return fold (build (MULT_EXPR, type, arg1,
+				  build_real (type, c)));
+	    }
+
+	  /* Convert x+x*c into x*(c+1).  */
+	  if (flag_unsafe_math_optimizations
+	      && TREE_CODE (arg1) == MULT_EXPR
+	      && TREE_CODE (TREE_OPERAND (arg1, 1)) == REAL_CST
+	      && ! TREE_CONSTANT_OVERFLOW (TREE_OPERAND (arg1, 1))
+	      && operand_equal_p (TREE_OPERAND (arg1, 0), arg0, 0))
+	    {
+	      REAL_VALUE_TYPE c;
+
+	      c = TREE_REAL_CST (TREE_OPERAND (arg1, 1));
+	      real_arithmetic (&c, PLUS_EXPR, &c, &dconst1);
+	      return fold (build (MULT_EXPR, type, arg0,
+				  build_real (type, c)));
+	    }
+
+	  /* Convert x*c1+x*c2 into x*(c1+c2).  */
+	  if (flag_unsafe_math_optimizations
+	      && TREE_CODE (arg0) == MULT_EXPR
+	      && TREE_CODE (arg1) == MULT_EXPR
+	      && TREE_CODE (TREE_OPERAND (arg0, 1)) == REAL_CST
+	      && ! TREE_CONSTANT_OVERFLOW (TREE_OPERAND (arg0, 1))
+	      && TREE_CODE (TREE_OPERAND (arg1, 1)) == REAL_CST
+	      && ! TREE_CONSTANT_OVERFLOW (TREE_OPERAND (arg1, 1))
+	      && operand_equal_p (TREE_OPERAND (arg0, 0),
+				  TREE_OPERAND (arg1, 0), 0))
+	    {
+	      REAL_VALUE_TYPE c1, c2;
+
+	      c1 = TREE_REAL_CST (TREE_OPERAND (arg0, 1));
+	      c2 = TREE_REAL_CST (TREE_OPERAND (arg1, 1));
+	      real_arithmetic (&c1, PLUS_EXPR, &c1, &c2);
+	      return fold (build (MULT_EXPR, type,
+				  TREE_OPERAND (arg0, 0),
+				  build_real (type, c1)));
+	    }
+	}
 
      bit_rotate:
       /* (A << C1) + (A >> C2) if A is unsigned and C1+C2 is the size of A
@@ -5954,15 +6012,6 @@ fold (tree expr)
 	      && real_minus_onep (arg1))
 	    return fold (build1 (NEGATE_EXPR, type, arg0));
 
-	  /* x*2 is x+x */
-	  if (! wins && real_twop (arg1)
-	      && (*lang_hooks.decls.global_bindings_p) () == 0
-	      && ! CONTAINS_PLACEHOLDER_P (arg0))
-	    {
-	      tree arg = save_expr (arg0);
-	      return fold (build (PLUS_EXPR, type, arg, arg));
-	    }
-
 	  if (flag_unsafe_math_optimizations)
 	    {
 	      enum built_in_function fcode0 = builtin_mathfn_code (arg0);

gcc/testsuite/ChangeLog

+2003-08-04  Roger Sayle  <roger@eyesopen.com>
+
+	* gcc.dg/20030804-1.c: New test case.
+
 2003-08-04  Alexandre Oliva  <aoliva@redhat.com>
 
 	* gcc.dg/cpp/separate-1.c: New test.

gcc/testsuite/gcc.dg/20030804-1.c

+/* Copyright (C) 2003 Free Software Foundation.
+
+   Check that constant folding of mathematical expressions doesn't
+   break anything.
+
+   Written by Roger Sayle, 3rd August 2003.  */
+
+/* { dg-do link } */
+/* { dg-options "-O2 -ffast-math" } */
+
+extern void link_error(void);
+
+void test(double x)
+{
+  if (x+x != 2.0*x)
+    link_error ();
+  if (x+x != x*2.0)
+    link_error ();
+
+  if (x+x+x != 3.0*x)
+    link_error ();
+  if (x+x+x != x*3.0)
+    link_error ();
+
+  if ((x+x)+x != 3.0*x)
+    link_error ();
+  if ((x+x)+x != x*3.0)
+    link_error ();
+
+  if (x+(x+x) != 3.0*x)
+    link_error ();
+  if (x+(x+x) != x*3.0)
+    link_error ();
+
+  if (x+4.0*x != 5.0*x)
+    link_error ();
+  if (x+4.0*x != x*5.0)
+    link_error ();
+  if (x+x*4.0 != 5.0*x)
+    link_error ();
+  if (x+x*4.0 != x*5.0)
+    link_error ();
+  if (4.0*x+x != 5.0*x)
+    link_error ();
+  if (4.0*x+x != x*5.0)
+    link_error ();
+  if (x*4.0+x != 5.0*x)
+    link_error ();
+  if (x*4.0+x != x*5.0)
+    link_error ();
+
+  if (3.0*x + 5.0*x != 8.0*x)
+    link_error ();
+  if (3.0*x + 5.0*x != x*8.0)
+    link_error ();
+  if (x*3.0 + 5.0*x != 8.0*x)
+    link_error ();
+  if (x*3.0 + 5.0*x != x*8.0)
+    link_error ();
+  if (3.0*x + x*5.0 != 8.0*x)
+    link_error ();
+  if (3.0*x + x*5.0 != x*8.0)
+    link_error ();
+  if (x*3.0 + x*5.0 != 8.0*x)
+    link_error ();
+  if (x*3.0 + x*5.0 != x*8.0)
+    link_error ();
+}
+
+int main()
+{
+  test(2.0);
+  return 0;
+}
+