From 73444c651ff4e30a66b18ae14f5a669994238076 Mon Sep 17 00:00:00 2001
From: uros <uros@138bc75d-0d04-0410-961f-82ee72b054a4>
Date: Mon, 21 Nov 2005 07:49:47 +0000
Subject: [PATCH]         * fold-const.c (fold_binary) <RDIV_EXPR>: Optimize A
 / A to 1.0         if we don't care about NaNs or Infinities.

testsuite:

        * gcc.dg/fold-div-2.c: New test.



git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@107282 138bc75d-0d04-0410-961f-82ee72b054a4
---
 gcc/ChangeLog                     |  5 +++++
 gcc/fold-const.c                  | 11 +++++++++++
 gcc/testsuite/ChangeLog           |  4 ++++
 gcc/testsuite/gcc.dg/fold-div-2.c | 13 +++++++++++++
 4 files changed, 33 insertions(+)
 create mode 100644 gcc/testsuite/gcc.dg/fold-div-2.c

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 630bebc1bbf..b4ff1f89445 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,8 @@
+2005-11-21  Uros Bizjak  <uros@kss-loka.si>
+
+	* fold-const.c (fold_binary) <RDIV_EXPR>: Optimize A / A to 1.0 
+	if we don't care about NaNs or Infinities.
+
 2005-11-20  Ian Lance Taylor  <ian@airs.com>
 
 	PR rtl-optimization/24883
diff --git a/gcc/fold-const.c b/gcc/fold-const.c
index c4dd4f955a7..e7f550b2038 100644
--- a/gcc/fold-const.c
+++ b/gcc/fold-const.c
@@ -8227,6 +8227,17 @@ fold_binary (enum tree_code code, tree type, tree op0, tree op1)
 	  && real_zerop (arg1))
 	return NULL_TREE;
 
+      /* Optimize A / A to 1.0 if we don't care about
+	 NaNs or Infinities.  */
+      if (! HONOR_NANS (TYPE_MODE (TREE_TYPE (arg0)))
+	  && ! HONOR_INFINITIES (TYPE_MODE (TREE_TYPE (arg0)))
+	  && operand_equal_p (arg0, arg1, 0))
+	{
+	  tree r = build_real (TREE_TYPE (arg0), dconst1);
+
+	  return omit_two_operands (type, r, arg0, arg1);
+	}
+
       /* (-A) / (-B) -> A / B  */
       if (TREE_CODE (arg0) == NEGATE_EXPR && negate_expr_p (arg1))
 	return fold_build2 (RDIV_EXPR, type,
diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index 1a05c183fec..045cf0a6e1a 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,7 @@
+2005-11-21  Uros Bizjak  <uros@kss-loka.si>
+
+	* gcc.dg/fold-div-2.c: New test.
+	
 2005-11-20  Ian Lance Taylor  <ian@airs.com>
 
 	PR rtl-optimization/24883
diff --git a/gcc/testsuite/gcc.dg/fold-div-2.c b/gcc/testsuite/gcc.dg/fold-div-2.c
new file mode 100644
index 00000000000..bfd07d1c482
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/fold-div-2.c
@@ -0,0 +1,13 @@
+/* { dg-do compile } */
+/* { dg-options "-ffinite-math-only -fdump-tree-gimple" } */
+
+double f(double x)
+{
+  return x / x;
+}
+
+/* Division should be turned into 1.0.  */
+
+/* { dg-final { scan-tree-dump-not " / " "gimple" } } */
+/* { dg-final { cleanup-tree-dump "gimple" } } */
+
-- 
2.11.4.GIT