From: Richard Guenther <rguenther@suse.de>
Date: Thu, 17 Jan 2008 12:17:24 +0000 (+0000)
Subject: re PR tree-optimization/34825 (ICE with -funsafe-math-optimizations)
X-Git-Tag: releases/gcc-4.3.0~573
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=8a5b57cdfd40c2996c755d4cc2707c5ea3c2ca67;p=thirdparty%2Fgcc.git

re PR tree-optimization/34825 (ICE with -funsafe-math-optimizations)

2008-01-17  Richard Guenther  <rguenther@suse.de>

	PR tree-optimization/34825
	* tree-ssa-math-opts.c (is_division_by): Do not recognize
	x / x as division to handle.

	* gcc.dg/pr34825.c: New testcase.

From-SVN: r131595
---

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 309c57f39ed0..170024205089 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,9 @@
+2008-01-17  Richard Guenther  <rguenther@suse.de>
+
+	PR tree-optimization/34825
+	* tree-ssa-math-opts.c (is_division_by): Do not recognize
+	x / x as division to handle.
+
 2008-01-16  John David Anglin  <dave.anglin@nrc-cnrc.gc.ca>
 
 	* pa64-hpux.h (LIB_SPEC): Add "-lpthread" in shared links if "-mt" or
diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index f732e1d4cd03..a4a95462c037 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,8 @@
+2008-01-17  Richard Guenther  <rguenther@suse.de>
+
+	PR tree-optimization/34825
+	* gcc.dg/pr34825.c: New testcase.
+
 2008-01-17  Richard Guenther  <rguenther@suse.de>
 
 	* gcc.c-torture/execute/20080117-1.c: New testcase.
diff --git a/gcc/testsuite/gcc.dg/pr34825.c b/gcc/testsuite/gcc.dg/pr34825.c
new file mode 100644
index 000000000000..40061bad6b53
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/pr34825.c
@@ -0,0 +1,8 @@
+/* { dg-do compile } */
+/* { dg-options "-O -funsafe-math-optimizations" } */
+
+double foo(double x, double y)
+{
+  return x == y ? x/y*x/y : 0;
+}
+
diff --git a/gcc/tree-ssa-math-opts.c b/gcc/tree-ssa-math-opts.c
index 543169ad9325..5a7bf8bc66dd 100644
--- a/gcc/tree-ssa-math-opts.c
+++ b/gcc/tree-ssa-math-opts.c
@@ -275,7 +275,11 @@ is_division_by (tree use_stmt, tree def)
 {
   return TREE_CODE (use_stmt) == GIMPLE_MODIFY_STMT
 	 && TREE_CODE (GIMPLE_STMT_OPERAND (use_stmt, 1)) == RDIV_EXPR
-	 && TREE_OPERAND (GIMPLE_STMT_OPERAND (use_stmt, 1), 1) == def;
+	 && TREE_OPERAND (GIMPLE_STMT_OPERAND (use_stmt, 1), 1) == def
+	 /* Do not recognize x / x as valid division, as we are getting
+	    confused later by replacing all immediate uses x in such
+	    a stmt.  */
+	 && TREE_OPERAND (GIMPLE_STMT_OPERAND (use_stmt, 1), 0) != def;
 }
 
 /* Walk the subset of the dominator tree rooted at OCC, setting the