re PR tree-optimization/70715 (SCEV failed to prove no-overflow-ness information...

	PR tree-optimization/70715
	* tree-ssa-loop-niter.c (loop_exits_before_overflow): Check equality
	after expanding BASE using expand_simple_operations.

	gcc/testsuite/ChangeLog
	PR tree-optimization/70715
	* gcc.dg/tree-ssa/scev-13.c: New test.

From-SVN: r235333

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 86bee074b69f96ffc59b3589ae44d004174e9e97..a3412c900298620fc0c577721c3cf50b5790ec18 100644 (file)
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,9 @@
+2016-04-21  Bin Cheng  <bin.cheng@arm.com>
+
+       PR tree-optimization/70715
+       * tree-ssa-loop-niter.c (loop_exits_before_overflow): Check equality
+       after expanding BASE using expand_simple_operations.
+
 2016-04-21  Marc Glisse  <marc.glisse@inria.fr>
 
        * match.pd (min(-x, -y), max(-x, -y), min(~x, ~y), max(~x, ~y)):

diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index 08f70405c52ed57066fa3f71804fc3b1605ae6aa..7a17aa2ebb63a75dfd2b719eda62d79be5091b0a 100644 (file)
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,8 @@
+2016-04-21  Bin Cheng  <bin.cheng@arm.com>
+
+       PR tree-optimization/70715
+       * gcc.dg/tree-ssa/scev-13.c: New test.
+
 2016-04-21  Marc Glisse  <marc.glisse@inria.fr>
 
        * gcc.dg/tree-ssa/minmax-2.c: New testcase.

diff --git a/gcc/testsuite/gcc.dg/tree-ssa/scev-13.c b/gcc/testsuite/gcc.dg/tree-ssa/scev-13.c
new file mode 100644 (file)
index 0000000..b9223c8
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/tree-ssa/scev-13.c
@@ -0,0 +1,15 @@
+/* { dg-do compile } */
+/* { dg-options "-O3 -fdump-tree-ldist" } */
+
+int
+foo (char *p, unsigned n)
+{
+  while(n--)
+    {
+      p[n]='A';
+    }
+  return 0;
+}
+
+/* Loop can be transformed into builtin memset since &p[n] is SCEV.  */
+/* { dg-final { scan-tree-dump "builtin_memset" "ldist" } } */

diff --git a/gcc/tree-ssa-loop-niter.c b/gcc/tree-ssa-loop-niter.c
index 81689fc1aa432d710dfaa0ca76fc30ab1f09c609..c61083e7fd3ea5ddd4d67ac65ecb2032aa32af41 100644 (file)
--- a/gcc/tree-ssa-loop-niter.c
+++ b/gcc/tree-ssa-loop-niter.c
@@ -4141,7 +4141,11 @@ loop_exits_before_overflow (tree base, tree step,
            continue;
 
          /* Done proving if this is a no-overflow control IV.  */
-         if (operand_equal_p (base, civ->base, 0))
+         if (operand_equal_p (base, civ->base, 0)
+             /* Control IV is recorded after expanding simple operations,
+                Here we compare it against expanded base too.  */
+             || operand_equal_p (expand_simple_operations (base),
+                                 civ->base, 0))
            return true;
 
          /* If this is a before stepping control IV, in other words, we have