[PATCH] Fix PR55331

[Richard Biener]

This is an alternate fix for PR55331, bootstrapped and tested on
x86_64-unknown-linux-gnu, applied.

Richard.

2012-11-16  Richard Biener  <rguent...@suse.de>

        PR middle-end/55331
        * gimple-fold.c (gimplify_and_update_call_from_tree): Replace
        stmt with a NOP instead of removing it.

        * g++.dg/opt/pr55331.C: New testcase.

Index: gcc/gimple-fold.c
===================================================================
--- gcc/gimple-fold.c   (revision 193816)
+++ gcc/gimple-fold.c   (working copy)
@@ -607,7 +607,7 @@ gimplify_and_update_call_from_tree (gimp
              unlink_stmt_vdef (stmt);
              release_defs (stmt);
            }
-         gsi_remove (si_p, true);
+         gsi_replace (si_p, gimple_build_nop (), true);
          return;
        }
     }
Index: gcc/testsuite/g++.dg/opt/pr55331.C
===================================================================
--- gcc/testsuite/g++.dg/opt/pr55331.C  (revision 0)
+++ gcc/testsuite/g++.dg/opt/pr55331.C  (working copy)
@@ -0,0 +1,14 @@
+// PR tree-optimization/55331
+// { dg-do compile }
+// { dg-options "-O2 -fno-tree-fre" }
+
+struct A {};
+
+void
+foo (A *p, bool x)
+{
+  A a;
+  char *e = (char *) (&a + 1);
+  if (x)
+    __builtin_memmove (p, &a, e - (char *) &a);
+}