From: jakub <jakub@138bc75d-0d04-0410-961f-82ee72b054a4>
Date: Thu, 15 Nov 2018 08:47:21 +0000 (+0000)
Subject: 	PR rtl-optimization/88018
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=a3f619a1b40509a8df861e0e4426e3967d8c5e66;p=thirdparty%2Fgcc.git

	PR rtl-optimization/88018
	* cfgrtl.c (fixup_abnormal_edges): Guard moving insns to fallthru edge
	on the presence of fallthru edge, rather than if it is a USE or not.

	* g++.dg/tsan/pr88018.C: New test.


git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@266174 138bc75d-0d04-0410-961f-82ee72b054a4
---

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 174ee432c4fa..4bf430757dca 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,9 @@
+2018-11-15  Jakub Jelinek  <jakub@redhat.com>
+
+	PR rtl-optimization/88018
+	* cfgrtl.c (fixup_abnormal_edges): Guard moving insns to fallthru edge
+	on the presence of fallthru edge, rather than if it is a USE or not.
+
 2018-11-15  Richard Biener  <rguenther@suse.de>
 
 	PR middle-end/87917
diff --git a/gcc/cfgrtl.c b/gcc/cfgrtl.c
index 741a3120a971..3d4a114cbbb9 100644
--- a/gcc/cfgrtl.c
+++ b/gcc/cfgrtl.c
@@ -3332,8 +3332,15 @@ fixup_abnormal_edges (void)
 			 If it's placed after a trapping call (i.e. that
 			 call is the last insn anyway), we have no fallthru
 			 edge.  Simply delete this use and don't try to insert
-			 on the non-existent edge.  */
-		      if (GET_CODE (PATTERN (insn)) != USE)
+			 on the non-existent edge.
+			 Similarly, sometimes a call that can throw is
+			 followed in the source with __builtin_unreachable (),
+			 meaning that there is UB if the call returns rather
+			 than throws.  If there weren't any instructions
+			 following such calls before, supposedly even the ones
+			 we've deleted aren't significant and can be
+			 removed.  */
+		      if (e)
 			{
 			  /* We're not deleting it, we're moving it.  */
 			  insn->set_undeleted ();
diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index 0bcd8e0711f4..3c6c47f6766c 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,8 @@
+2018-11-15  Jakub Jelinek  <jakub@redhat.com>
+
+	PR rtl-optimization/88018
+	* g++.dg/tsan/pr88018.C: New test.
+
 2018-11-15  Richard Biener  <rguenther@suse.de>
 
 	PR middle-end/87917