re PR tree-optimization/46076 (constant propagation and compile-time math no longer...

2011-01-11  Richard Guenther  <rguenther@suse.de>

	PR tree-optimization/46076
	* tree-ssa.c (useless_type_conversion_p): Conversions from
	unprototyped to empty argument list function types are useless.

	* gcc.dg/tree-ssa/pr46076.c: New testcase.

From-SVN: r168665

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 35b4a69..9724eee 100644 (file)
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,5 +1,11 @@
 2011-01-11  Richard Guenther  <rguenther@suse.de>
 
+       PR tree-optimization/46076
+       * tree-ssa.c (useless_type_conversion_p): Conversions from
+       unprototyped to empty argument list function types are useless.
+
+2011-01-11  Richard Guenther  <rguenther@suse.de>
+
        PR middle-end/45235
        * emit-rtl.c (set_mem_attributes_minus_bitpos): Do not mark
        volatile MEMs as MEM_READONLY_P.

diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index 710431c..adb6740 100644 (file)
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,8 @@
+2011-01-11  Richard Guenther  <rguenther@suse.de>
+
+       PR tree-optimization/46076
+       * gcc.dg/tree-ssa/pr46076.c: New testcase.
+
 2011-01-11  Jeff Law <law@redhat.com>
 
        * PR tree-optimization/47086

diff --git a/gcc/testsuite/gcc.dg/tree-ssa/pr46076.c b/gcc/testsuite/gcc.dg/tree-ssa/pr46076.c
new file mode 100644 (file)
index 0000000..a2777a6
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/tree-ssa/pr46076.c
@@ -0,0 +1,27 @@
+/* { dg-do link } */
+/* { dg-options "-O2" } */
+
+extern void link_error (void);
+
+typedef unsigned char(*Calculable)(void);
+
+static unsigned char one() { return 1; }
+static unsigned char two() { return 2; }
+
+static int
+print(Calculable calculate)
+{
+  return calculate() + calculate() + 1;
+}
+
+int
+main()
+{
+  /* Make sure we perform indirect inlining of one and two and optimize
+     the result to a constant.  */
+  if (print(one) != 3)
+    link_error ();
+  if (print(two) != 5)
+    link_error ();
+  return 0;
+}

diff --git a/gcc/tree-ssa.c b/gcc/tree-ssa.c
index 7bd01f8..aa797e2 100644 (file)
--- a/gcc/tree-ssa.c
+++ b/gcc/tree-ssa.c
@@ -1410,6 +1410,11 @@ useless_type_conversion_p (tree outer_type, tree inner_type)
       if (!prototype_p (outer_type))
        return true;
 
+      /* A conversion between unprototyped and empty argument list is ok.  */
+      if (TYPE_ARG_TYPES (outer_type) == void_list_node
+         && !prototype_p (inner_type))
+       return true;
+
       /* If the unqualified argument types are compatible the conversion
         is useless.  */
       if (TYPE_ARG_TYPES (outer_type) == TYPE_ARG_TYPES (inner_type))