gcc/gcc7-pr81325.patch

2017-09-15  Jakub Jelinek  <jakub@redhat.com>

	Backported from mainline
	2017-09-14  Jakub Jelinek  <jakub@redhat.com>
 
	PR target/81325
	* cfgbuild.c (find_bb_boundaries): Ignore debug insns in decisions
	if and where to split a bb, except for splitting before debug insn
	sequences followed by non-label real insn.  Delete debug insns
	in between basic blocks.

	* g++.dg/cpp0x/pr81325.C: New test.

--- gcc/cfgbuild.c	(revision 252751)
+++ gcc/cfgbuild.c	(revision 252752)
@@ -442,9 +442,10 @@ find_bb_boundaries (basic_block bb)
   rtx_insn *end = BB_END (bb), *x;
   rtx_jump_table_data *table;
   rtx_insn *flow_transfer_insn = NULL;
+  rtx_insn *debug_insn = NULL;
   edge fallthru = NULL;
 
-  if (insn == BB_END (bb))
+  if (insn == end)
     return;
 
   if (LABEL_P (insn))
@@ -455,27 +456,49 @@ find_bb_boundaries (basic_block bb)
     {
       enum rtx_code code = GET_CODE (insn);
 
+      if (code == DEBUG_INSN)
+	{
+	  if (flow_transfer_insn && !debug_insn)
+	    debug_insn = insn;
+	}
       /* In case we've previously seen an insn that effects a control
 	 flow transfer, split the block.  */
-      if ((flow_transfer_insn || code == CODE_LABEL)
-	  && inside_basic_block_p (insn))
+      else if ((flow_transfer_insn || code == CODE_LABEL)
+	       && inside_basic_block_p (insn))
 	{
-	  fallthru = split_block (bb, PREV_INSN (insn));
+	  rtx_insn *prev = PREV_INSN (insn);
+
+	  /* If the first non-debug inside_basic_block_p insn after a control
+	     flow transfer is not a label, split the block before the debug
+	     insn instead of before the non-debug insn, so that the debug
+	     insns are not lost.  */
+	  if (debug_insn && code != CODE_LABEL && code != BARRIER)
+	    prev = PREV_INSN (debug_insn);
+	  fallthru = split_block (bb, prev);
 	  if (flow_transfer_insn)
 	    {
 	      BB_END (bb) = flow_transfer_insn;
 
+	      rtx_insn *next;
 	      /* Clean up the bb field for the insns between the blocks.  */
 	      for (x = NEXT_INSN (flow_transfer_insn);
 		   x != BB_HEAD (fallthru->dest);
-		   x = NEXT_INSN (x))
-		if (!BARRIER_P (x))
-		  set_block_for_insn (x, NULL);
+		   x = next)
+		{
+		  next = NEXT_INSN (x);
+		  /* Debug insns should not be in between basic blocks,
+		     drop them on the floor.  */
+		  if (DEBUG_INSN_P (x))
+		    delete_insn (x);
+		  else if (!BARRIER_P (x))
+		    set_block_for_insn (x, NULL);
+		}
 	    }
 
 	  bb = fallthru->dest;
 	  remove_edge (fallthru);
 	  flow_transfer_insn = NULL;
+	  debug_insn = NULL;
 	  if (code == CODE_LABEL && LABEL_ALT_ENTRY_P (insn))
 	    make_edge (ENTRY_BLOCK_PTR_FOR_FN (cfun), bb, 0);
 	}
@@ -498,17 +521,23 @@ find_bb_boundaries (basic_block bb)
   /* In case expander replaced normal insn by sequence terminating by
      return and barrier, or possibly other sequence not behaving like
      ordinary jump, we need to take care and move basic block boundary.  */
-  if (flow_transfer_insn)
+  if (flow_transfer_insn && flow_transfer_insn != end)
     {
       BB_END (bb) = flow_transfer_insn;
 
       /* Clean up the bb field for the insns that do not belong to BB.  */
-      x = flow_transfer_insn;
-      while (x != end)
+      rtx_insn *next;
+      for (x = NEXT_INSN (flow_transfer_insn); ; x = next)
 	{
-	  x = NEXT_INSN (x);
-	  if (!BARRIER_P (x))
+	  next = NEXT_INSN (x);
+	  /* Debug insns should not be in between basic blocks,
+	     drop them on the floor.  */
+	  if (DEBUG_INSN_P (x))
+	    delete_insn (x);
+	  else if (!BARRIER_P (x))
 	    set_block_for_insn (x, NULL);
+	  if (x == end)
+	    break;
 	}
     }
 
--- gcc/testsuite/g++.dg/cpp0x/pr81325.C	(nonexistent)
+++ gcc/testsuite/g++.dg/cpp0x/pr81325.C	(revision 252752)
@@ -0,0 +1,84 @@
+// PR target/81325
+// { dg-do compile { target c++11 } }
+// { dg-options "-O2 -fcompare-debug" }
+
+struct A { A(const char *, const int & = 0); };
+template <typename> struct B;
+template <typename> struct C {
+  int _M_i;
+  void m_fn1() { __atomic_fetch_add(&_M_i, 0, __ATOMIC_RELAXED); }
+};
+struct D {
+  int *Data;
+  long Length = 0;
+  D(int) : Data() {}
+};
+template <> struct B<int> : C<int> {};
+struct F {
+  B<int> RefCount;
+  void m_fn2() { RefCount.m_fn1(); }
+};
+struct G {
+  F *Obj;
+  G(const G &p1) : Obj(p1.Obj) {
+    if (Obj) {
+      F *a = 0;
+      a->m_fn2();
+    }
+  }
+};
+struct H {
+  int CPlusPlus : 1;
+};
+struct I {
+  enum {} KindId;
+};
+template <typename ResultT, typename ArgT> struct J {
+  void operator()();
+  ResultT operator()(ArgT) {}
+};
+struct K {
+  int AllowBind;
+  I SupportedKind;
+  I RestrictKind;
+  G Implementation;
+};
+struct L {
+  L(int) : Implementation(Implementation) {}
+  K Implementation;
+};
+struct M {
+  int Param1;
+};
+struct N {
+  N(int, L &p2) : Param2(p2) {}
+  L Param2;
+};
+struct O {
+  L m_fn3();
+};
+L ignoringImpCasts(L);
+J<O, L> b;
+L hasName(const A &);
+M hasOverloadedOperatorName(D);
+J<O, int> c;
+struct P {
+  void m_fn4(L, int);
+};
+struct Q {
+  void m_fn5(P *);
+};
+H d;
+void Q::m_fn5(P *p1) {
+  if (!d.CPlusPlus) {
+    c();
+    L e = 0, f = ignoringImpCasts(e);
+    b(ignoringImpCasts(f)).m_fn3();
+  }
+  hasOverloadedOperatorName(0);
+  hasName("");
+  L g = 0;
+  N(0, g);
+  L h(0);
+  p1->m_fn4(h, 0);
+}