* emit-rtl.c (dconstm2, dconsthalf): New real constants.

	(init_emit_once): Initialize dconstm2 and dconsthalf here.
	* real.h (dconstm2, dconsthalf): Add prototypes here.
	* real.c (real_sqrt): Use dconsthalf rather than local copy.
	* builtins.c (fold_builtin): When optimizing sqrt(exp(x)) as
	exp(x/2.0) remember to fold the division if possible.
	Fold sin(0.0) as 0.0, cos(0.0) as 1.0, pow(x,1.0) as x,
	pow(x,-1.0) as 1.0/x, pow(x,2.0) as x*x, pow(x,-2.0) as
	1.0/(x*x) and pow(x,0.5) as sqrt(x).

	* gcc.dg/builtins-3.c: Add new tests for sin and cos.
	* gcc.dg/builtins-7.c: New test case.
	* gcc.dg/builtins-8.c: New test case.


git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@65088 138bc75d-0d04-0410-961f-82ee72b054a4

9 files changed, 218 insertions, 15 deletions

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index fd3e32a6af9..c7b59f0071f 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,15 @@
+2003-03-31  Roger Sayle  <roger@eyesopen.com>
+
+	* emit-rtl.c (dconstm2, dconsthalf): New real constants.
+	(init_emit_once): Initialize dconstm2 and dconsthalf here.
+	* real.h (dconstm2, dconsthalf): Add prototypes here.
+	* real.c (real_sqrt): Use dconsthalf rather than local copy.
+	* builtins.c (fold_builtin): When optimizing sqrt(exp(x)) as
+	exp(x/2.0) remember to fold the division if possible.
+	Fold sin(0.0) as 0.0, cos(0.0) as 1.0, pow(x,1.0) as x,
+	pow(x,-1.0) as 1.0/x, pow(x,2.0) as x*x, pow(x,-2.0) as
+	1.0/(x*x) and pow(x,0.5) as sqrt(x).
+
 2003-03-31  Kazu Hirata  <kazu@cs.umass.edu>
 
 	* config/h8300/h8300.md (a new peephole2): New.
diff --git a/gcc/builtins.c b/gcc/builtins.c
index b6fe4b4fbe6..d446185c8c5 100644
--- a/gcc/builtins.c
+++ b/gcc/builtins.c
@@ -4743,15 +4743,41 @@ fold_builtin (exp)
 		  || fcode == BUILT_IN_EXPL))
 	    {
 	      tree expfn = TREE_OPERAND (TREE_OPERAND (arg, 0), 0);
-	      arg = build (RDIV_EXPR, type,
-			   TREE_VALUE (TREE_OPERAND (arg, 1)),
-			   build_real (type, dconst2));
+	      arg = fold (build (RDIV_EXPR, type,
+				 TREE_VALUE (TREE_OPERAND (arg, 1)),
+				 build_real (type, dconst2)));
 	      arglist = build_tree_list (NULL_TREE, arg);
 	      return build_function_call_expr (expfn, arglist);
 	    }
 	}
       break;
 
+    case BUILT_IN_SIN:
+    case BUILT_IN_SINF:
+    case BUILT_IN_SINL:
+      if (validate_arglist (arglist, REAL_TYPE, VOID_TYPE))
+	{
+	  tree arg = TREE_VALUE (arglist);
+
+	  /* Optimize sin(0.0) = 0.0.  */
+	  if (real_zerop (arg))
+	    return build_real (type, dconst0);
+	}
+      break;
+
+    case BUILT_IN_COS:
+    case BUILT_IN_COSF:
+    case BUILT_IN_COSL:
+      if (validate_arglist (arglist, REAL_TYPE, VOID_TYPE))
+	{
+	  tree arg = TREE_VALUE (arglist);
+
+	  /* Optimize cos(0.0) = 1.0.  */
+	  if (real_zerop (arg))
+	    return build_real (type, dconst1);
+	}
+      break;
+
     case BUILT_IN_EXP:
     case BUILT_IN_EXPF:
     case BUILT_IN_EXPL:
@@ -4816,13 +4842,75 @@ fold_builtin (exp)
 	  tree arg0 = TREE_VALUE (arglist);
 	  tree arg1 = TREE_VALUE (TREE_CHAIN (arglist));
 
-	  /* Optimize pow(x,0.0) = 1.0.  */
-	  if (real_zerop (arg1))
-	    return omit_one_operand (type, build_real (type, dconst1), arg0);
-
 	  /* Optimize pow(1.0,y) = 1.0.  */
 	  if (real_onep (arg0))
 	    return omit_one_operand (type, build_real (type, dconst1), arg1);
+
+	  if (TREE_CODE (arg1) == REAL_CST
+	      && ! TREE_CONSTANT_OVERFLOW (arg1))
+	    {
+	      REAL_VALUE_TYPE c;
+	      c = TREE_REAL_CST (arg1);
+
+	      /* Optimize pow(x,0.0) = 1.0.  */
+	      if (REAL_VALUES_EQUAL (c, dconst0))
+		return omit_one_operand (type, build_real (type, dconst1),
+					 arg0);
+
+	      /* Optimize pow(x,1.0) = x.  */
+	      if (REAL_VALUES_EQUAL (c, dconst1))
+		return arg0;
+
+	      /* Optimize pow(x,-1.0) = 1.0/x.  */
+	      if (REAL_VALUES_EQUAL (c, dconstm1))
+		return fold (build (RDIV_EXPR, type,
+				    build_real (type, dconst1),
+				    arg0));
+
+	      /* Optimize pow(x,2.0) = x*x.  */
+	      if (REAL_VALUES_EQUAL (c, dconst2)
+		  && (*lang_hooks.decls.global_bindings_p) () == 0
+		  && ! contains_placeholder_p (arg0))
+		{
+		  arg0 = save_expr (arg0);
+		  return fold (build (MULT_EXPR, type, arg0, arg0));
+		}
+
+	      /* Optimize pow(x,-2.0) = 1.0/(x*x).  */
+	      if (flag_unsafe_math_optimizations
+		  && REAL_VALUES_EQUAL (c, dconstm2)
+		  && (*lang_hooks.decls.global_bindings_p) () == 0
+		  && ! contains_placeholder_p (arg0))
+		{
+		  arg0 = save_expr (arg0);
+		  return fold (build (RDIV_EXPR, type,
+				      build_real (type, dconst1),
+				      fold (build (MULT_EXPR, type,
+						   arg0, arg0))));
+		}
+
+	      /* Optimize pow(x,0.5) = sqrt(x).  */
+	      if (flag_unsafe_math_optimizations
+		  && REAL_VALUES_EQUAL (c, dconsthalf))
+		{
+		  tree sqrtfn;
+
+		  if (fcode == BUILT_IN_POW)
+		    sqrtfn = implicit_built_in_decls[BUILT_IN_SQRT];
+		  else if (fcode == BUILT_IN_POWF)
+		    sqrtfn = implicit_built_in_decls[BUILT_IN_SQRTF];
+		  else if (fcode == BUILT_IN_POWL)
+		    sqrtfn = implicit_built_in_decls[BUILT_IN_SQRTL];
+		  else
+		    sqrtfn = NULL_TREE;
+
+		  if (sqrtfn != NULL_TREE)
+		    {
+		      tree arglist = build_tree_list (NULL_TREE, arg0);
+		      return build_function_call_expr (sqrtfn, arglist);
+		    }
+		}
+	    }
 	}
       break;
 
diff --git a/gcc/emit-rtl.c b/gcc/emit-rtl.c
index ad30637ee0a..4aab67494d4 100644
--- a/gcc/emit-rtl.c
+++ b/gcc/emit-rtl.c
@@ -111,6 +111,8 @@ REAL_VALUE_TYPE dconst0;
 REAL_VALUE_TYPE dconst1;
 REAL_VALUE_TYPE dconst2;
 REAL_VALUE_TYPE dconstm1;
+REAL_VALUE_TYPE dconstm2;
+REAL_VALUE_TYPE dconsthalf;
 
 /* All references to the following fixed hard registers go through
    these unique rtl objects.  On machines where the frame-pointer and
@@ -5552,6 +5554,10 @@ init_emit_once (line_numbers)
   REAL_VALUE_FROM_INT (dconst1,   1,  0, double_mode);
   REAL_VALUE_FROM_INT (dconst2,   2,  0, double_mode);
   REAL_VALUE_FROM_INT (dconstm1, -1, -1, double_mode);
+  REAL_VALUE_FROM_INT (dconstm2, -2, -1, double_mode);
+
+  dconsthalf = dconst1;
+  dconsthalf.exp--;
 
   for (i = 0; i <= 2; i++)
     {
diff --git a/gcc/real.c b/gcc/real.c
index f6074f99639..04bf718a743 100644
--- a/gcc/real.c
+++ b/gcc/real.c
@@ -4423,7 +4423,6 @@ real_sqrt (r, mode, x)
      const REAL_VALUE_TYPE *x;
 {
   static REAL_VALUE_TYPE halfthree;
-  static REAL_VALUE_TYPE half;
   static bool init = false;
   REAL_VALUE_TYPE h, t, i;
   int iter, exp;
@@ -4452,8 +4451,7 @@ real_sqrt (r, mode, x)
 
   if (!init)
     {
-      real_arithmetic (&half, RDIV_EXPR, &dconst1, &dconst2);
-      real_arithmetic (&halfthree, PLUS_EXPR, &dconst1, &half);
+      real_arithmetic (&halfthree, PLUS_EXPR, &dconst1, &dconsthalf);
       init = true;
     }
 
@@ -4467,7 +4465,7 @@ real_sqrt (r, mode, x)
       /* i(n+1) = i(n) * (1.5 - 0.5*i(n)*i(n)*x).  */
       real_arithmetic (&t, MULT_EXPR, x, &i);
       real_arithmetic (&h, MULT_EXPR, &t, &i);
-      real_arithmetic (&t, MULT_EXPR, &h, &half);
+      real_arithmetic (&t, MULT_EXPR, &h, &dconsthalf);
       real_arithmetic (&h, MINUS_EXPR, &halfthree, &t);
       real_arithmetic (&t, MULT_EXPR, &i, &h);
 
@@ -4484,7 +4482,7 @@ real_sqrt (r, mode, x)
   real_arithmetic (&h, MULT_EXPR, &t, &i);
   real_arithmetic (&i, MINUS_EXPR, &dconst1, &h);
   real_arithmetic (&h, MULT_EXPR, &t, &i);
-  real_arithmetic (&i, MULT_EXPR, &half, &h);
+  real_arithmetic (&i, MULT_EXPR, &dconsthalf, &h);
   real_arithmetic (&h, PLUS_EXPR, &t, &i);
 
   /* ??? We need a Tuckerman test to get the last bit.  */
diff --git a/gcc/real.h b/gcc/real.h
index d16231acae8..9507af2270d 100644
--- a/gcc/real.h
+++ b/gcc/real.h
@@ -322,12 +322,14 @@ extern void real_ldexp		PARAMS ((REAL_VALUE_TYPE *,
 
 /* **** End of software floating point emulator interface macros **** */
 
-/* Constant real values 0, 1, 2, and -1.  */
+/* Constant real values 0, 1, 2, -1, -2 and 0.5.  */
 
 extern REAL_VALUE_TYPE dconst0;
 extern REAL_VALUE_TYPE dconst1;
 extern REAL_VALUE_TYPE dconst2;
 extern REAL_VALUE_TYPE dconstm1;
+extern REAL_VALUE_TYPE dconstm2;
+extern REAL_VALUE_TYPE dconsthalf;
 
 /* Function to return a real value (not a tree node)
    from a given integer constant.  */
diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index 2469ea4ed73..fdc97e104e2 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,9 @@
+2003-03-31  Roger Sayle  <roger@eyesopen.com>
+
+	* gcc.dg/builtins-3.c: Add new tests for sin and cos.
+	* gcc.dg/builtins-7.c: New test case.
+	* gcc.dg/builtins-8.c: New test case.
+
 2003-03-31  Richard Sandiford  <rsandifo@redhat.com>
 
 	* gcc.c-torture/execute/ieee/20030331-1.c: New test.
diff --git a/gcc/testsuite/gcc.dg/builtins-3.c b/gcc/testsuite/gcc.dg/builtins-3.c
index 49bea5e126e..3c2dbfd7f52 100644
--- a/gcc/testsuite/gcc.dg/builtins-3.c
+++ b/gcc/testsuite/gcc.dg/builtins-3.c
@@ -1,7 +1,7 @@
-/* Copyright (C) 2002  Free Software Foundation.
+/* Copyright (C) 2002, 2003  Free Software Foundation.
 
    Verify that built-in math function constant folding of constant
-   arguments is correctly performed by the by the compiler.
+   arguments is correctly performed by the compiler.
 
    Written by Roger Sayle, 16th August 2002.  */
 
@@ -24,6 +24,12 @@ int main()
   if (log (1.0) != 0.0)
     link_error ();
 
+  if (sin (0.0) != 0.0)
+    link_error ();
+
+  if (cos (0.0) != 1.0)
+    link_error ();
+
 
   if (sqrtf (0.0f) != 0.0f)
     link_error ();
@@ -37,6 +43,12 @@ int main()
   if (logf (1.0f) != 0.0f)
     link_error ();
 
+  if (sinf (0.0f) != 0.0f)
+    link_error ();
+
+  if (cosf (0.0f) != 1.0f)
+    link_error ();
+
 
   if (sqrtl (0.0l) != 0.0l)
     link_error ();
@@ -50,6 +62,12 @@ int main()
   if (logl (1.0l) != 0.0l)
     link_error ();
 
+  if (sinl (0.0l) != 0.0l)
+    link_error ();
+
+  if (cosl (0.0l) != 1.0l)
+    link_error ();
+
   return 0;
 }
 
diff --git a/gcc/testsuite/gcc.dg/builtins-7.c b/gcc/testsuite/gcc.dg/builtins-7.c
new file mode 100644
index 00000000000..84c0e154fa0
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/builtins-7.c
@@ -0,0 +1,39 @@
+/* Copyright (C) 2003  Free Software Foundation.
+
+   Verify that built-in math function constant folding of constant
+   arguments is correctly performed by the by the compiler.
+
+   Written by Roger Sayle, 30th March 2003.  */
+
+/* { dg-do link } */
+/* { dg-options "-O2 -ffast-math" } */
+
+extern void link_error(void);
+
+void test(double x)
+{
+  if (pow (x, 1.0) != x)
+    link_error ();
+}
+
+void testf(float x)
+{
+  if (powf (x, 1.0f) != x)
+    link_error ();
+}
+
+void testl(long double x)
+{
+  if (powl (x, 1.0l) != x)
+    link_error ();
+}
+
+int main()
+{
+  test (2.0);
+  testf (2.0f);
+  testl (2.0l);
+
+  return 0;
+}
+
diff --git a/gcc/testsuite/gcc.dg/builtins-8.c b/gcc/testsuite/gcc.dg/builtins-8.c
new file mode 100644
index 00000000000..99d1a70d01a
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/builtins-8.c
@@ -0,0 +1,34 @@
+/* Copyright (C) 2003  Free Software Foundation.
+
+   Verify that built-in math function constant folding of functions
+   with one constant argument is correctly performed by the compiler.
+
+   Written by Roger Sayle, 30th March 2003.  */
+
+/* { dg-do run } */
+/* { dg-options "-O2 -ffast-math" } */
+
+extern void abort(void);
+
+void test(double x)
+{
+  if (pow(x,-1.0) != 1.0/x)
+    abort ();
+
+  if (pow(x,2.0) != x*x)
+    abort ();
+
+  if (pow(x,-2.0) != 1.0/(x*x))
+    abort ();
+
+  if (pow(x,0.5) != sqrt(x))
+    abort ();
+}
+
+int main()
+{
+  test (1.0);
+  test (2.0);
+  return 0;
+}
+