PR tree-optimization/21847

	* tree-ssa-dce.c (mark_stmt_if_obviously_necessary): With
	-fnon-call-exceptions, also mark statements inherently
	necessary if they may throw.


git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@100714 138bc75d-0d04-0410-961f-82ee72b054a4

1 files changed, 9 insertions, 0 deletions

diff --git a/gcc/tree-ssa-dce.c b/gcc/tree-ssa-dce.c
index 65c85eb54e9..f6e62dc9c7f 100644
--- a/gcc/tree-ssa-dce.c
+++ b/gcc/tree-ssa-dce.c
@@ -279,6 +279,15 @@ mark_stmt_if_obviously_necessary (tree stmt, bool aggressive)
   tree op, def;
   ssa_op_iter iter;
 
+  /* With non-call exceptions, we have to assume that all statements could
+     throw.  If a statement may throw, it is inherently necessary.  */
+  if (flag_non_call_exceptions
+      && tree_could_throw_p (stmt))
+    {
+      mark_stmt_necessary (stmt, true);
+      return;
+    }
+
   /* Statements that are implicitly live.  Most function calls, asm and return
      statements are required.  Labels and BIND_EXPR nodes are kept because
      they are control flow, and we have no way of knowing whether they can be