From: Richard Biener <rguenther@suse.de>
Date: Fri, 21 Apr 2017 12:09:20 +0000 (+0000)
Subject: re PR tree-optimization/78847 (pointer arithmetic from c++ ranged-based for loop... 
X-Git-Url: https://git.libre-soc.org/?a=commitdiff_plain;h=bb1bc604a852c38afd0df9d2f6a66a0e1a80db34;p=gcc.git

re PR tree-optimization/78847 (pointer arithmetic from c++ ranged-based for loop not optimized)

2017-04-21  Richard Biener  <rguenther@suse.de>

	PR tree-optimization/78847
	* fold-const.c (split_tree): Handle POINTER_PLUS_EXPR.

	* g++.dg/tree-ssa/pr78847.C: New testcase.

From-SVN: r247061
---

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 370d0b4d1b1..359273ef092 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,8 @@
+2017-04-21  Richard Biener  <rguenther@suse.de>
+
+	PR tree-optimization/78847
+	* fold-const.c (split_tree): Handle POINTER_PLUS_EXPR.
+
 2017-04-21  Richard Biener  <rguenther@suse.de>
 
 	* tree.h (build_qualified_type): Annotate with CXX_MEM_STAT_INFO.
diff --git a/gcc/fold-const.c b/gcc/fold-const.c
index 770162251f2..4ae21fb0d2f 100644
--- a/gcc/fold-const.c
+++ b/gcc/fold-const.c
@@ -798,8 +798,11 @@ split_tree (location_t loc, tree in, tree type, enum tree_code code,
 		  though the C standard doesn't say so) for integers because
 		  the value is not affected.  For reals, the value might be
 		  affected, so we can't.  */
-	       && ((code == PLUS_EXPR && TREE_CODE (in) == MINUS_EXPR)
-		   || (code == MINUS_EXPR && TREE_CODE (in) == PLUS_EXPR))))
+	       && ((code == PLUS_EXPR && TREE_CODE (in) == POINTER_PLUS_EXPR)
+		   || (code == PLUS_EXPR && TREE_CODE (in) == MINUS_EXPR)
+		   || (code == MINUS_EXPR
+		       && (TREE_CODE (in) == PLUS_EXPR
+			   || TREE_CODE (in) == POINTER_PLUS_EXPR)))))
     {
       tree op0 = TREE_OPERAND (in, 0);
       tree op1 = TREE_OPERAND (in, 1);
diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index a40f9ffda33..414f27972bf 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,8 @@
+2017-04-21  Richard Biener  <rguenther@suse.de>
+
+	PR tree-optimization/78847
+	* g++.dg/tree-ssa/pr78847.C: New testcase.
+
 2017-04-21  Jakub Jelinek  <jakub@redhat.com>
 
 	PR c/80468
diff --git a/gcc/testsuite/g++.dg/tree-ssa/pr78847.C b/gcc/testsuite/g++.dg/tree-ssa/pr78847.C
new file mode 100644
index 00000000000..d5a83943804
--- /dev/null
+++ b/gcc/testsuite/g++.dg/tree-ssa/pr78847.C
@@ -0,0 +1,26 @@
+/* { dg-do compile } */
+/* { dg-require-effective-target c++14 } */
+/* { dg-options "-O3 -fdump-tree-ldist" } */
+
+#include <stddef.h>
+#include <cstring>
+#include <experimental/string_view>
+
+using string_view = std::experimental::string_view;
+
+class Foo {
+    constexpr static size_t Length = 9;
+    char ascii_[Length];
+public:
+    Foo();
+    string_view view() const {
+	return string_view(ascii_, Length);
+    }
+};
+
+void testWithLoopValue(const Foo foo, size_t ptr, char *buf_) {
+    for (auto c : foo.view())
+      buf_[ptr++] = c;
+}
+
+/* { dg-final { scan-tree-dump "memcpy\[^\n\r\]*, 9\\);" "ldist" } } */