I have found some little nits that I will point out in a reply to this
message.
Balaji:
In Joseph's review on October 19, 2012
(http://gcc.gnu.org/ml/gcc-patches/2012-10/msg01838.html) he mentioned:
Say expr1 through expr9 are expressions with side effects, and you have:
expr1[expr2:expr3:expr4] = expr5[expr6:expr7:expr8] + expr9;
The spec says "However, in such a statement, a sub-expression with rank
zero is evaluated only once." - that is, each of the nine expressions is
evaluated once. I don't see any calls to save_expr to ensure these
semantics, or any testcases that verify that they are adhered to.
If I understand Joseph's comment, this is still broken on the branch.
For example, in the example below:
array[func1() + 11 : func2() + 22 : func3() + 33] = 666;
...the function calls should only be called once, yet currently we generate:
D.1739 = 0;
<D.1740>:
D.1769 = func2 ();
D.1770 = D.1769 + 22;
if (D.1739 < D.1770) goto <D.1741>; else goto <D.1742>;
<D.1741>:
D.1771 = func1 (); <-- BOO HISS
D.1772 = D.1771 + 11;
D.1773 = func3 (); <-- BOO HISS
D.1774 = D.1773 + 33;
D.1775 = D.1739 * D.1774;
D.1776 = D.1772 + D.1775;
array[D.1776] = 666;
D.1739 = D.1739 + 1;
goto <D.1740>;
<D.1742>:
As you can see, func1() and func3() are being called repeatedly within
the loop.
I am adding the attached execute test to the harness. If my
understanding is correct, this test should pass.
Joseph, please let me know if I misunderstood things in some way.
Committed to cilkplus-merge branch.
commit 4447dcf380a08f74bf5b91fd84d7013cbbb34ee8
Author: Aldy Hernandez <al...@redhat.com>
Date: Wed Mar 20 16:47:02 2013 -0500
Add new test to verify that the array index, limit, and stride are
only evaluated once.
diff --git
a/gcc/testsuite/gcc.dg/cilk-plus/array_notation/execute/side-effects-1.c
b/gcc/testsuite/gcc.dg/cilk-plus/array_notation/execute/side-effects-1.c
new file mode 100644
index 0000000..1845862
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/cilk-plus/array_notation/execute/side-effects-1.c
@@ -0,0 +1,23 @@
+/* Test that the array index, limit, and stride are evaluated only
+ once. */
+
+int array[1000];
+
+int func1_times = 0;
+int func2_times = 0;
+int func3_times = 0;
+int func1() { func1_times++; return 0; }
+int func2() { func2_times++; return 0; }
+int func3() { func3_times++; return 0; }
+
+int main()
+{
+ array[func1() + 11 : func2() + 22 : func3() + 33] = 666;
+
+ if (func1_times != 1
+ || func2_times != 1
+ || func3_times != 1)
+ abort();
+
+ return 0;
+}
