[gcc/devel/c++-modules] middle-end/93273 - fix sinking clobbers across backedges

[Nathan Sidwell]

https://gcc.gnu.org/g:37e27de43133b87ceb529d863f0d1f54d87cf2d8

commit 37e27de43133b87ceb529d863f0d1f54d87cf2d8
Author: Richard Biener <rguenther@suse.de>
Date:   Wed Jan 15 13:29:25 2020 +0100

    middle-end/93273 - fix sinking clobbers across backedges
    
    The previous work to fix PR93199 didn't take into account backedges
    when defering insertion.  The following simply avoids to defer in that
    case since we know we'll not take secondary opportunities there.
    
    2020-01-15  Richard Biener  <rguenther@suse.de>
    
            PR middle-end/93273
            * tree-eh.c (sink_clobbers): If we already visited the destination
            block do not defer insertion.
            (pass_lower_eh_dispatch::execute): Maintain BB_VISITED for
            the purpose of defered insertion.
    
    	* g++.dg/torture/pr93273.C: New testcase.

Diff:
---
 gcc/ChangeLog                          |  8 ++++++++
 gcc/testsuite/ChangeLog                |  5 +++++
 gcc/testsuite/g++.dg/torture/pr93273.C | 12 ++++++++++++
 gcc/tree-eh.c                          |  4 +++-
 4 files changed, 28 insertions(+), 1 deletion(-)

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index e0c961d..0ad4e97 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,11 @@
+2020-01-15  Richard Biener  <rguenther@suse.de>
+
+	PR middle-end/93273
+	* tree-eh.c (sink_clobbers): If we already visited the destination
+	block do not defer insertion.
+	(pass_lower_eh_dispatch::execute): Maintain BB_VISITED for
+	the purpose of defered insertion.
+
 2020-01-15  Jakub Jelinek  <jakub@redhat.com>
 
 	* BASE-VER: Bump to 10.0.1.
diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index 0f0f177..da638d3 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,8 @@
+2020-01-15  Richard Biener  <rguenther@suse.de>
+
+	PR middle-end/93273
+	* g++.dg/torture/pr93273.C: New testcase.
+
 2020-01-15  Richard Sandiford  <richard.sandiford@arm.com>
 
 	PR tree-optimization/93247
diff --git a/gcc/testsuite/g++.dg/torture/pr93273.C b/gcc/testsuite/g++.dg/torture/pr93273.C
new file mode 100644
index 0000000..229642b
--- /dev/null
+++ b/gcc/testsuite/g++.dg/torture/pr93273.C
@@ -0,0 +1,12 @@
+// { dg-do compile }
+
+void _setjmp(void *);
+struct S { ~S(); };
+void * (* fn)();
+void f();
+void g()
+{
+  S s;
+  _setjmp(fn());
+  []{ f(); }();
+}
diff --git a/gcc/tree-eh.c b/gcc/tree-eh.c
index dc80f57..454b22c 100644
--- a/gcc/tree-eh.c
+++ b/gcc/tree-eh.c
@@ -3622,7 +3622,7 @@ sink_clobbers (basic_block bb,
 
   gimple *first_sunk = NULL;
   gimple *last_sunk = NULL;
-  if (sunk)
+  if (sunk && !(succbb->flags & BB_VISITED))
     dgsi = gsi_start (sunk[succbb->index]);
   else
     dgsi = gsi_after_labels (succbb);
@@ -3910,6 +3910,7 @@ pass_lower_eh_dispatch::execute (function *fun)
 	  else if (!any_resx_to_process)
 	    sink_clobbers (bb, NULL, &any_resx_to_process);
 	}
+      bb->flags &= ~BB_VISITED;
     }
   if (redirected)
     {
@@ -3940,6 +3941,7 @@ pass_lower_eh_dispatch::execute (function *fun)
 	      gsi_insert_seq_before (&gsi, sunk[bb->index], GSI_NEW_STMT);
 	      sunk[bb->index] = NULL;
 	    }
+	  bb->flags |= BB_VISITED;
 	}
       free (rpo);
       free (sunk);