rhbz 300121: optimization bug

5 files changed, 57 insertions, 2 deletions

diff --git a/ChangeLog b/ChangeLog
index 861ee020..28bcf9d5 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,11 @@
+2007-09-21  Frank Ch. Eigler  <fche@elastic.org>
+
+	rhbz #300121
+	* elaborate.cxx (dead_stmtexpr_remover): Add visit_if_statement,
+	visit_foreach_loop, visit_for_loop): Support elision for unbraced
+	statement bodies.
+	(visit_expr_statement): Assert absence of unexpected nesting.
+
 2007-09-17  David Smith  <dsmith@redhat.com>
 
 	PR 1154
diff --git a/elaborate.cxx b/elaborate.cxx
index 094fbbac..621e1a72 100644
--- a/elaborate.cxx
+++ b/elaborate.cxx
@@ -1577,6 +1577,9 @@ struct dead_stmtexpr_remover: public traversing_visitor
     session(s), relaxed_p(r), current_stmt(0) {}
 
   void visit_block (block *s);
+  void visit_if_statement (if_statement* s);
+  void visit_foreach_loop (foreach_loop *s);
+  void visit_for_loop (for_loop *s);
   // XXX: and other places where stmt_expr's might be nested
 
   void visit_expr_statement (expr_statement *s);
@@ -1595,6 +1598,39 @@ dead_stmtexpr_remover::visit_block (block *s)
     }
 }
 
+void
+dead_stmtexpr_remover::visit_if_statement (if_statement *s)
+{
+  statement** last_stmt = current_stmt;
+  current_stmt = & s->thenblock;
+  s->thenblock->visit (this);
+  if (s->elseblock)
+    {
+      current_stmt = & s->elseblock;
+      s->elseblock->visit (this);
+    }
+  current_stmt = last_stmt;
+}
+
+void
+dead_stmtexpr_remover::visit_foreach_loop (foreach_loop *s)
+{
+  statement** last_stmt = current_stmt;
+  current_stmt = & s->block;
+  s->block->visit (this);
+  current_stmt = last_stmt;
+}
+
+void
+dead_stmtexpr_remover::visit_for_loop (for_loop *s)
+{
+  statement** last_stmt = current_stmt;
+  current_stmt = & s->block;
+  s->block->visit (this);
+  current_stmt = last_stmt;
+}
+
+
 
 void
 dead_stmtexpr_remover::visit_expr_statement (expr_statement *s)
@@ -1614,7 +1650,8 @@ dead_stmtexpr_remover::visit_expr_statement (expr_statement *s)
 
   varuse_collecting_visitor vut;
   s->value->visit (& vut);
-  if (vut.side_effect_free_wrt (focal_vars))
+  if (vut.side_effect_free_wrt (focal_vars) &&
+      *current_stmt == s) // we're not nested any deeper than expected 
     {
       if (session.verbose>2)
         clog << "Eliding side-effect-free expression "
diff --git a/testsuite/ChangeLog b/testsuite/ChangeLog
index 6f523a83..ec9c74aa 100644
--- a/testsuite/ChangeLog
+++ b/testsuite/ChangeLog
@@ -1,3 +1,7 @@
+2007-09-21  Frank Ch. Eigler  <fche@elastic.org>
+
+	* systemtap.base/optim.exp/stp: New test for rhbz# 300121.
+
 2007-09-18  David Smith  <dsmith@redhat.com>
 
 	* systemtap.base/procfs.exp: New test case.
diff --git a/testsuite/systemtap.base/optim.exp b/testsuite/systemtap.base/optim.exp
index 23735af6..a2bfd3ab 100644
--- a/testsuite/systemtap.base/optim.exp
+++ b/testsuite/systemtap.base/optim.exp
@@ -5,9 +5,10 @@ set ok 0
 expect {
 	-timeout 120
 	-re {i=1} { incr ok }
+	-re {j=2} { incr ok }
 	timeout { fail "$test (timeout)" }
 	eof { }
 }
 close
 wait
-if {$ok == 1} { pass $test } { fail $test }
+if {$ok == 2} { pass $test } { fail $test }
diff --git a/testsuite/systemtap.base/optim.stp b/testsuite/systemtap.base/optim.stp
index 6ca722a6..915a65da 100644
--- a/testsuite/systemtap.base/optim.stp
+++ b/testsuite/systemtap.base/optim.stp
@@ -3,7 +3,12 @@ function func(i) {
         array[i++] = 0;
         return i;
 }
+function bart() { # rhbz# 300121
+	if (1) var=2 else dummy=0
+	return var
+}
 probe begin {
   printf ("i=%d\n", func(0))
+  printf ("j=%d\n", bart())
   exit ()
 }