From: Uros Bizjak <ubizjak@gmail.com>
Date: Mon, 11 Jun 2007 09:09:24 +0000 (+0200)
Subject: re PR middle-end/32279 (Fold 1.0/sqrt(x/y) to sqrt(y/x))
X-Git-Tag: releases/gcc-4.3.0~4525
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=f1da2df1e9642bc8660abcd83af2ad8980d42ce0;p=thirdparty%2Fgcc.git

re PR middle-end/32279 (Fold 1.0/sqrt(x/y) to sqrt(y/x))

	PR middle-end/32279
	* fold-const (fold_binary) [RDIV_EXPR]: Optimize a/sqrt(b/c)
	into a*sqrt(c/b) if flag_unsafe_math_optimizations is set.

testsuite/ChangeLog:

	PR middle-end/32279
	* gcc.dg/builtins-11.c: Also check folding of a/sqrt(b/c).

From-SVN: r125614
---

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index c16ab208d34c..a026ca1d3c3e 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,9 @@
+2007-06-11  Uros Bizjak  <ubizjak@gmail.com>
+
+	PR middle-end/32279
+	* fold-const (fold_binary) [RDIV_EXPR]: Optimize a/sqrt(b/c)
+	into a*sqrt(c/b) if flag_unsafe_math_optimizations is set.
+
 2007-06-10  Jan Sjodin  <jan.sjodin@amd.com>
 	    Sebastian Pop  <sebpop@gmail.com>
 
diff --git a/gcc/fold-const.c b/gcc/fold-const.c
index bc6d6022415e..5c7effe3e344 100644
--- a/gcc/fold-const.c
+++ b/gcc/fold-const.c
@@ -10555,6 +10555,24 @@ fold_binary (enum tree_code code, tree type, tree op0, tree op1)
 		}
 	    }
 
+	  /* Optimize a/sqrt(b/c) into a*sqrt(c/b).  */
+	  if (BUILTIN_SQRT_P (fcode1))
+	    {
+	      tree rootarg = CALL_EXPR_ARG (arg1, 0);
+
+	      if (TREE_CODE (rootarg) == RDIV_EXPR)
+		{
+		  tree rootfn = TREE_OPERAND (CALL_EXPR_FN (arg1), 0);
+		  tree b = TREE_OPERAND (rootarg, 0);
+		  tree c = TREE_OPERAND (rootarg, 1);
+
+		  tree tmp = fold_build2 (RDIV_EXPR, type, c, b);
+
+		  tmp = build_call_expr (rootfn, 1, tmp);
+		  return fold_build2 (MULT_EXPR, type, arg0, tmp);
+		}
+	    }
+
 	  /* Optimize x/expN(y) into x*expN(-y).  */
 	  if (BUILTIN_EXPONENT_P (fcode1))
 	    {
diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index 32d88ade40ec..f7d76fa848e2 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,8 @@
+2007-06-11  Uros Bizjak  <ubizjak@gmail.com>
+
+	PR middle-end/32279
+	* gcc.dg/builtins-11.c: Also check folding of a/sqrt(b/c).
+
 2007-06-10  Jerry DeLisle  <jvdelisle@gcc.gnu.org>
 
 	PR libgfortran/32235
diff --git a/gcc/testsuite/gcc.dg/builtins-11.c b/gcc/testsuite/gcc.dg/builtins-11.c
index a2ff257b9ee4..ba4689201c40 100644
--- a/gcc/testsuite/gcc.dg/builtins-11.c
+++ b/gcc/testsuite/gcc.dg/builtins-11.c
@@ -1,4 +1,4 @@
-/* Copyright (C) 2003 Free Software Foundation.
+/* Copyright (C) 2003,2007 Free Software Foundation.
 
    Check that constant folding of built-in math functions doesn't
    break anything and produces the expected results.
@@ -36,6 +36,9 @@ void test(double x, double y, double z)
 
   if (x/pow(y,z) != x*pow(y,-z))
     link_error ();
+
+  if (x/sqrt(y/z) != x*sqrt(z/y))
+    link_error ();
 }
 
 int main()