re PR debug/77844 (Compilation of simple C++ example exhaust memory)

	PR debug/77844
	* valtrack.c: Include rtl-iter.h.
	(struct rtx_subst_pair): Add insn field.
	(propagate_for_debug_subst): If pair->to contains at least 2
	regs, create a DEBUG_INSN with a debug temp before pair->insn
	and replace from with the debug temp instead of pair->to.
	(propagate_for_debug): Initialize p.insn.
	* combine.c (insn_uid_check): New inline function.
	(INSN_COST, LOG_LINKS): Use it instead of INSN_UID.
	(find_single_use, combine_instructions,
	cant_combine_insn_p, try_combine): Use NONDEBUG_INSN_P instead of
	INSN_P.

	* g++.dg/opt/pr77844.C: New test.

From-SVN: r243662

gcc/ChangeLog

+2016-12-14  Jakub Jelinek  <jakub@redhat.com>
+
+	PR debug/77844
+	* valtrack.c: Include rtl-iter.h.
+	(struct rtx_subst_pair): Add insn field.
+	(propagate_for_debug_subst): If pair->to contains at least 2
+	regs, create a DEBUG_INSN with a debug temp before pair->insn
+	and replace from with the debug temp instead of pair->to.
+	(propagate_for_debug): Initialize p.insn.
+	* combine.c (insn_uid_check): New inline function.
+	(INSN_COST, LOG_LINKS): Use it instead of INSN_UID.
+	(find_single_use, combine_instructions,
+	cant_combine_insn_p, try_combine): Use NONDEBUG_INSN_P instead of
+	INSN_P.
+
 2016-12-14  Martin Sebor  <msebor@redhat.com>
 
 	PR c/17308

gcc/combine.c

@@ -327,8 +327,16 @@ struct insn_link {
 
 static struct insn_link **uid_log_links;
 
-#define INSN_COST(INSN)		(uid_insn_cost[INSN_UID (INSN)])
-#define LOG_LINKS(INSN)		(uid_log_links[INSN_UID (INSN)])
+static inline int
+insn_uid_check (const_rtx insn)
+{
+  int uid = INSN_UID (insn);
+  gcc_checking_assert (uid <= max_uid_known);
+  return uid;
+}
+
+#define INSN_COST(INSN)		(uid_insn_cost[insn_uid_check (INSN)])
+#define LOG_LINKS(INSN)		(uid_log_links[insn_uid_check (INSN)])
 
 #define FOR_EACH_LOG_LINK(L, INSN)				\
   for ((L) = LOG_LINKS (INSN); (L); (L) = (L)->next)
@@ -676,7 +684,7 @@ find_single_use (rtx dest, rtx_insn *insn, rtx_insn **ploc)
   for (next = NEXT_INSN (insn);
        next && BLOCK_FOR_INSN (next) == bb;
        next = NEXT_INSN (next))
-    if (INSN_P (next) && dead_or_set_p (next, dest))
+    if (NONDEBUG_INSN_P (next) && dead_or_set_p (next, dest))
       {
 	FOR_EACH_LOG_LINK (link, next)
 	  if (link->insn == insn && link->regno == REGNO (dest))
@@ -1127,7 +1135,7 @@ combine_instructions (rtx_insn *f, unsigned int nregs)
 
   int new_direct_jump_p = 0;
 
-  for (first = f; first && !INSN_P (first); )
+  for (first = f; first && !NONDEBUG_INSN_P (first); )
     first = NEXT_INSN (first);
   if (!first)
     return 0;
@@ -2275,7 +2283,7 @@ cant_combine_insn_p (rtx_insn *insn)
   /* If this isn't really an insn, we can't do anything.
      This can occur when flow deletes an insn that it has merged into an
      auto-increment address.  */
-  if (! INSN_P (insn))
+  if (!NONDEBUG_INSN_P (insn))
     return 1;
 
   /* Never combine loads and stores involving hard regs that are likely
@@ -4178,7 +4186,8 @@ try_combine (rtx_insn *i3, rtx_insn *i2, rtx_insn *i1, rtx_insn *i0,
 		    || insn != BB_HEAD (this_basic_block->next_bb));
 	   insn = NEXT_INSN (insn))
 	{
-	  if (INSN_P (insn) && reg_referenced_p (ni2dest, PATTERN (insn)))
+	  if (NONDEBUG_INSN_P (insn)
+	      && reg_referenced_p (ni2dest, PATTERN (insn)))
 	    {
 	      FOR_EACH_LOG_LINK (link, insn)
 		if (link->insn == i3)
@@ -4319,9 +4328,9 @@ try_combine (rtx_insn *i3, rtx_insn *i2, rtx_insn *i1, rtx_insn *i0,
 	    for (temp_insn = NEXT_INSN (i2);
 		 temp_insn
 		 && (this_basic_block->next_bb == EXIT_BLOCK_PTR_FOR_FN (cfun)
-			  || BB_HEAD (this_basic_block) != temp_insn);
+		     || BB_HEAD (this_basic_block) != temp_insn);
 		 temp_insn = NEXT_INSN (temp_insn))
-	      if (temp_insn != i3 && INSN_P (temp_insn))
+	      if (temp_insn != i3 && NONDEBUG_INSN_P (temp_insn))
 		FOR_EACH_LOG_LINK (link, temp_insn)
 		  if (link->insn == i2)
 		    link->insn = i3;

gcc/testsuite/ChangeLog

+2016-12-14  Jakub Jelinek  <jakub@redhat.com>
+
+	PR debug/77844
+	* g++.dg/opt/pr77844.C: New test.
+
 2016-12-14  Martin Sebor  <msebor@redhat.com>
 
 	PR c/17308

gcc/testsuite/g++.dg/opt/pr77844.C

+// PR debug/77844
+// { dg-do compile }
+// { dg-options "-O3 -g" }
+
+#include <vector>
+
+void
+foo (std::vector<bool>& v, int i, int j)
+{
+  for (int k = 0; k < 5; ++k)
+    v[5 * i + k] = v[5 * i + k] | v[5 * j + k];
+}
+
+void
+bar (std::vector<bool>& v, int i, int j)
+{
+  for (int k = 0; k < 5; ++k)
+    v[5 * i + k] = v[5 * i + k] ^ v[5 * j + k];
+}
+
+void
+baz (std::vector<bool>& v)
+{
+  foo (v, 4, 1);
+  foo (v, 4, 2);
+  foo (v, 4, 3);
+  foo (v, 4, 4);
+  bar (v, 4, 1);
+  bar (v, 4, 2);
+  bar (v, 4, 3);
+  bar (v, 4, 4);
+}

gcc/valtrack.c

@@ -29,6 +29,7 @@ along with GCC; see the file COPYING3.  If not see
 #include "regs.h"
 #include "memmodel.h"
 #include "emit-rtl.h"
+#include "rtl-iter.h"
 
 /* gen_lowpart_no_emit hook implementation for DEBUG_INSNs.  In DEBUG_INSNs,
    all lowpart SUBREGs are valid, despite what the machine requires for
@@ -145,6 +146,7 @@ struct rtx_subst_pair
 {
   rtx to;
   bool adjusted;
+  rtx_insn *insn;
 };
 
 /* DATA points to an rtx_subst_pair.  Return the value that should be
@@ -162,6 +164,23 @@ propagate_for_debug_subst (rtx from, const_rtx old_rtx, void *data)
       pair->adjusted = true;
       pair->to = cleanup_auto_inc_dec (pair->to, VOIDmode);
       pair->to = make_compound_operation (pair->to, SET);
+      /* Avoid propagation from growing DEBUG_INSN expressions too much.  */
+      int cnt = 0;
+      subrtx_iterator::array_type array;
+      FOR_EACH_SUBRTX (iter, array, pair->to, ALL)
+	if (REG_P (*iter) && ++cnt > 1)
+	  {
+	    rtx dval = make_debug_expr_from_rtl (old_rtx);
+	    /* Emit a debug bind insn.  */
+	    rtx bind
+	      = gen_rtx_VAR_LOCATION (GET_MODE (old_rtx),
+				      DEBUG_EXPR_TREE_DECL (dval), pair->to,
+				      VAR_INIT_STATUS_INITIALIZED);
+	    rtx_insn *bind_insn = emit_debug_insn_before (bind, pair->insn);
+	    df_insn_rescan (bind_insn);
+	    pair->to = dval;
+	    break;
+	  }
       return pair->to;
     }
   return copy_rtx (pair->to);
@@ -182,6 +201,7 @@ propagate_for_debug (rtx_insn *insn, rtx_insn *last, rtx dest, rtx src,
   struct rtx_subst_pair p;
   p.to = src;
   p.adjusted = false;
+  p.insn = NEXT_INSN (insn);
 
   next = NEXT_INSN (insn);
   last = NEXT_INSN (last);