[PATCH] More IPA-PTA fixes

[Richard Guenther]

IPA-PTA makes it necessary to properly condition tail-calls.

Bootstrapped and tested on x86_64-unknown-linux-gnu, applied to trunk.

Richard.

2010-05-02  Richard Guenther  <rguenther@suse.de>

        PR tree-optimization/43879
        * tree-tailcall.c (find_tail_calls): Clobbers also prevent
        tail calls.

        * gcc.dg/torture/pr43879-3.c: New testcase.


Index: gcc/tree-tailcall.c
===================================================================
*** gcc/tree-tailcall.c	(revision 158973)
--- gcc/tree-tailcall.c	(working copy)
*************** find_tail_calls (basic_block bb, struct
*** 460,466 ****
      {
        if (TREE_CODE (var) != PARM_DECL
  	  && auto_var_in_fn_p (var, cfun->decl)
! 	  && ref_maybe_used_by_stmt_p (call, var))
  	return;
      }
  
--- 460,467 ----
      {
        if (TREE_CODE (var) != PARM_DECL
  	  && auto_var_in_fn_p (var, cfun->decl)
! 	  && (ref_maybe_used_by_stmt_p (call, var)
! 	      || call_may_clobber_ref_p (call, var)))
  	return;
      }
  
Index: gcc/testsuite/gcc.dg/torture/pr43879-3.c
===================================================================
*** gcc/testsuite/gcc.dg/torture/pr43879-3.c	(revision 0)
--- gcc/testsuite/gcc.dg/torture/pr43879-3.c	(revision 0)
***************
*** 0 ****
--- 1,41 ----
+ /* { dg-do run } */
+ /* { dg-options "-fipa-pta" } */
+ 
+ typedef unsigned long ulong;
+ 
+ int __attribute__((noinline, noclone))
+ f4 (int a, int b, int c, int d, int e)
+ {
+   return a + b + c + d + e;
+ }
+ 
+ void __attribute__((noinline, noclone))
+ f3 (int *p)
+ {
+   *p = f4(1, 2, 3, 4, 5);
+ }
+ 
+ void __attribute__((noinline, noclone))
+ f2 ()
+ {
+   int unused;
+   f3 (&unused);
+ }
+ 
+ void __attribute__((noinline, noclone))
+ f1 (ulong e, ulong f)
+ {
+   if (e > 5 || f > 5) __builtin_abort();
+   f2 ();
+ }
+ 
+ 
+ int main()
+ {
+  ulong e, f;
+  for (e = 5; e > 0; e--)
+    for (f = 5; f > 0; f--)
+      f1(e, f);
+  return 0;
+ }
+