From: Jakub Jelinek <jakub@redhat.com>
Date: Fri, 30 Aug 2019 11:42:17 +0000 (+0200)
Subject: backport: re PR target/89188 (ICE in pre_and_rev_post_order_compute, at cfganal.c... 
X-Git-Tag: releases/gcc-7.5.0~261
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=034762a6652508da2c51a1232ad41f9ce158c9fd;p=thirdparty%2Fgcc.git

backport: re PR target/89188 (ICE in pre_and_rev_post_order_compute, at cfganal.c:1055)

	Backported from mainline
	2019-02-05  Jakub Jelinek  <jakub@redhat.com>

	PR target/89188
	* dce.c (delete_unmarked_insns): Don't remove no-op moves if they
	can throw, non-call exceptions are enabled and we can't delete
	dead exceptions or alter cfg.  Set must_clean if
	delete_insn_and_edges returns true, don't set it blindly for calls.

	* g++.dg/opt/pr89188.C: New test.

From-SVN: r275101
---

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index ff921609067c..4f5bbd3b542e 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -3,6 +3,12 @@
 	Backported from mainline
 	2019-02-05  Jakub Jelinek  <jakub@redhat.com>
 
+	PR target/89188
+	* dce.c (delete_unmarked_insns): Don't remove no-op moves if they
+	can throw, non-call exceptions are enabled and we can't delete
+	dead exceptions or alter cfg.  Set must_clean if
+	delete_insn_and_edges returns true, don't set it blindly for calls.
+
 	PR rtl-optimization/89195
 	* combine.c (make_extraction): For MEMs, don't extract bytes outside
 	of the original MEM.
diff --git a/gcc/dce.c b/gcc/dce.c
index aaa2fef692bc..afdd6d8b4008 100644
--- a/gcc/dce.c
+++ b/gcc/dce.c
@@ -574,7 +574,12 @@ delete_unmarked_insns (void)
 	  rtx turn_into_use = NULL_RTX;
 
 	  /* Always delete no-op moves.  */
-	  if (noop_move_p (insn))
+	  if (noop_move_p (insn)
+	      /* Unless the no-op move can throw and we are not allowed
+		 to alter cfg.  */
+	      && (!cfun->can_throw_non_call_exceptions
+		  || (cfun->can_delete_dead_exceptions && can_alter_cfg)
+		  || insn_nothrow_p (insn)))
 	    {
 	      if (RTX_FRAME_RELATED_P (insn))
 		turn_into_use
@@ -617,12 +622,6 @@ delete_unmarked_insns (void)
 	     for the destination regs in order to avoid dangling notes.  */
 	  remove_reg_equal_equiv_notes_for_defs (insn);
 
-	  /* If a pure or const call is deleted, this may make the cfg
-	     have unreachable blocks.  We rememeber this and call
-	     delete_unreachable_blocks at the end.  */
-	  if (CALL_P (insn))
-	    must_clean = true;
-
 	  if (turn_into_use)
 	    {
 	      /* Don't remove frame related noop moves if they cary
@@ -635,7 +634,7 @@ delete_unmarked_insns (void)
 	    }
 	  else
 	    /* Now delete the insn.  */
-	    delete_insn_and_edges (insn);
+	    must_clean |= delete_insn_and_edges (insn);
 	}
 
   /* Deleted a pure or const call.  */
diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index 063fbdbca951..27a09c534ef8 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -3,6 +3,9 @@
 	Backported from mainline
 	2019-02-05  Jakub Jelinek  <jakub@redhat.com>
 
+	PR target/89188
+	* g++.dg/opt/pr89188.C: New test.
+
 	PR rtl-optimization/89195
 	* gcc.c-torture/execute/pr89195.c: New test.
 
diff --git a/gcc/testsuite/g++.dg/opt/pr89188.C b/gcc/testsuite/g++.dg/opt/pr89188.C
new file mode 100644
index 000000000000..cb0ea7968db3
--- /dev/null
+++ b/gcc/testsuite/g++.dg/opt/pr89188.C
@@ -0,0 +1,13 @@
+// PR target/89188
+// { dg-do compile { target c++11 } }
+// { dg-options "-Og -flive-range-shrinkage -fnon-call-exceptions" }
+
+struct Ax {
+  int n, a[];
+};
+
+int i = 12345678;
+int main() {
+  static Ax s{456, i};
+  ((s.a[0]) ? (void)0 : (void)0);
+}