From: jiwang <jiwang@138bc75d-0d04-0410-961f-82ee72b054a4>
Date: Mon, 23 Nov 2015 12:14:05 +0000 (+0000)
Subject: [Patch] Drop constant overflow flag in adjust_range_with_scev when possible
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=39a9f2bea17b2d74c71ecac457c6771d7116390f;p=thirdparty%2Fgcc.git

[Patch] Drop constant overflow flag in adjust_range_with_scev when possible

2015-11-23  Richard Biener  <rguenth@gcc.gnu.com>
            Jiong Wang  <jiong.wang@arm.com>

gcc/
  PR tree-optimization/68317
  PR tree-optimization/68326
  * tree-vrp.c (adjust_range_with_scev): Call drop_tree_overflow if the
  final min and max are not infinity.

gcc/testsuite/
  * gcc.dg/pr68317.c: New testcase.



git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@230754 138bc75d-0d04-0410-961f-82ee72b054a4
---

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 530cf7810f97..b1d0918ced97 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,11 @@
+2015-11-23  Richard Biener  <rguenth@gcc.gnu.org>
+	    Jiong Wang  <jiong.wang@arm.com>
+
+	PR tree-optimization/68317
+	PR tree-optimization/68326
+	* tree-vrp.c (adjust_range_with_scev): Call drop_tree_overflow if the
+	final min and max are not infinity.
+
 2015-11-23  Ilya Enkovich  <enkovich.gnu@gmail.com>
 	    Richard Biener  <rguenther@suse.de>
 
diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index 142347de8018..1c60e503b992 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,10 @@
+2015-11-23  Richard Biener  <rguenther@suse.de>
+	    Jiong Wang  <jiong.wang@arm.com>
+
+	PR tree-optimization/68317
+	PR tree-optimization/68326
+	* gcc.dg/pr68317.c: New testcase.
+
 2015-11-23  Ilya Enkovich  <enkovich.gnu@gmail.com>
 
 	PR tree-optimization/68327
diff --git a/gcc/testsuite/gcc.dg/pr68317.c b/gcc/testsuite/gcc.dg/pr68317.c
new file mode 100644
index 000000000000..7b5656395886
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/pr68317.c
@@ -0,0 +1,15 @@
+/* { dg-do compile } */
+/* { dg-options "-O2" } */
+
+void bar (int);
+
+void
+foo ()
+{
+ int index = 0;
+
+ for (index; index <= 10; index--)
+   /* Result of the following multiply will overflow
+      when converted to signed int.  */
+   bar ((0xcafe + index) * 0xdead);
+}
diff --git a/gcc/tree-vrp.c b/gcc/tree-vrp.c
index f2c948c2be1b..70011908acbf 100644
--- a/gcc/tree-vrp.c
+++ b/gcc/tree-vrp.c
@@ -4323,6 +4323,17 @@ adjust_range_with_scev (value_range *vr, struct loop *loop,
 	  && is_positive_overflow_infinity (max)))
     return;
 
+  /* Even for valid range info, sometimes overflow flag will leak in.
+     As GIMPLE IL should have no constants with TREE_OVERFLOW set, we
+     drop them except for +-overflow_infinity which still need special
+     handling in vrp pass.  */
+  if (TREE_OVERFLOW_P (min)
+      && ! is_negative_overflow_infinity (min))
+    min = drop_tree_overflow (min);
+  if (TREE_OVERFLOW_P (max)
+      && ! is_positive_overflow_infinity (max))
+    max = drop_tree_overflow (max);
+
   set_value_range (vr, VR_RANGE, min, max, vr->equiv);
 }