[PATCH, PR 60461] Fix loop condition at the end of ipa_modify_call_arguments

[Martin Jambor]

Hi,

the reference re-building part of ipa_modify_call_arguments has a
stupid bug in the while loop condition, which means it does not look
at statements produced by force_gimple_operand_gsi which may lead to
bugs such as PR 60461.

The 4.8 branch does not have this code and does not exhibit the bug so
for th time being I'm leaving the code alone there.

I have bootstrapped and tested the following patch on x86_64-linux on
trunk and will commit it there shortly as obvious.

Thanks,

Martin


2014-03-13  Martin Jambor  <mjam...@suse.cz>

        PR lto/60461
        * ipa-prop.c (ipa_modify_call_arguments): Fix iteration condition.

testsuite/
        * gcc.dg/lto/pr60461_0.c: New test.

diff --git a/gcc/ipa-prop.c b/gcc/ipa-prop.c
index 4fb916a..efe8c7a 100644
--- a/gcc/ipa-prop.c
+++ b/gcc/ipa-prop.c
@@ -3901,7 +3901,7 @@ ipa_modify_call_arguments (struct cgraph_edge *cs, gimple 
stmt,
       gsi_prev (&gsi);
     }
   while ((gsi_end_p (prev_gsi) && !gsi_end_p (gsi))
-        || (!gsi_end_p (prev_gsi) && gsi_stmt (gsi) == gsi_stmt (prev_gsi)));
+        || (!gsi_end_p (prev_gsi) && gsi_stmt (gsi) != gsi_stmt (prev_gsi)));
 }
 
 /* If the expression *EXPR should be replaced by a reduction of a parameter, do
diff --git a/gcc/testsuite/gcc.dg/lto/pr60461_0.c 
b/gcc/testsuite/gcc.dg/lto/pr60461_0.c
new file mode 100644
index 0000000..cad6a8d
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/lto/pr60461_0.c
@@ -0,0 +1,37 @@
+/* { dg-lto-do link } */
+/* { dg-lto-options {{-Os -flto} } } */
+
+
+struct S
+{
+  int f1;
+  int f2;
+} a[1] = { {0, 0} }; 
+
+int b, c;
+
+static unsigned short fn1 (struct S);
+
+void
+fn2 ()
+{
+  for (; c;)
+    ;
+  b = 0;
+  fn1 (a[0]);
+}
+
+unsigned short
+fn1 (struct S p)
+{
+  if (p.f1)
+    fn2 ();
+  return 0;
+}
+
+int
+main ()
+{
+  fn2 ();
+  return 0;
+}