From: Richard Biener <rguenther@suse.de>
Date: Mon, 26 Nov 2018 15:53:48 +0000 (+0000)
Subject: re PR c++/84281 (Heap grows indefinitely)
X-Git-Tag: releases/gcc-7.4.0~15
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=1a2397397d7893a6f6206da9b78a77ed21e828b2;p=thirdparty%2Fgcc.git

re PR c++/84281 (Heap grows indefinitely)

	PR c++/84281

2018-02-12  Richard Biener  <rguenther@suse.de>

	* constexpr.c (cxx_eval_vec_init_1): Use a RANGE_EXPR to compact
	uniform constructors and delay allocating them fully.

From-SVN: r266469
---

diff --git a/gcc/cp/ChangeLog b/gcc/cp/ChangeLog
index 3392176ce26d..03c30c3b1229 100644
--- a/gcc/cp/ChangeLog
+++ b/gcc/cp/ChangeLog
@@ -1,3 +1,9 @@
+2018-11-26  Richard Biener  <rguenther@suse.de>
+
+	PR c++/84281
+	* constexpr.c (cxx_eval_vec_init_1): Use a RANGE_EXPR to compact
+	uniform constructors and delay allocating them fully.
+
 2018-11-26  Jason Merrill  <jason@redhat.com>
 
 	PR c++/87075 - ICE with constexpr array initialization.
diff --git a/gcc/cp/constexpr.c b/gcc/cp/constexpr.c
index 48e821903ac0..cfd6a3a0e6e1 100644
--- a/gcc/cp/constexpr.c
+++ b/gcc/cp/constexpr.c
@@ -2843,7 +2843,6 @@ cxx_eval_vec_init_1 (const constexpr_ctx *ctx, tree atype, tree init,
   unsigned HOST_WIDE_INT max = tree_to_uhwi (array_type_nelts_top (atype));
   verify_ctor_sanity (ctx, atype);
   vec<constructor_elt, va_gc> **p = &CONSTRUCTOR_ELTS (ctx->ctor);
-  vec_alloc (*p, max + 1);
   bool pre_init = false;
   unsigned HOST_WIDE_INT i;
 
@@ -2939,13 +2938,14 @@ cxx_eval_vec_init_1 (const constexpr_ctx *ctx, tree atype, tree init,
 	{
 	  if (new_ctx.ctor != ctx->ctor)
 	    eltinit = new_ctx.ctor;
-	  for (i = 1; i < max; ++i)
-	    {
-	      idx = build_int_cst (size_type_node, i);
-	      CONSTRUCTOR_APPEND_ELT (*p, idx, unshare_constructor (eltinit));
-	    }
+	  tree range = build2 (RANGE_EXPR, size_type_node,
+			       build_int_cst (size_type_node, 1),
+			       build_int_cst (size_type_node, max - 1));
+	  CONSTRUCTOR_APPEND_ELT (*p, range, unshare_constructor (eltinit));
 	  break;
 	}
+      else if (i == 0)
+	vec_safe_reserve (*p, max);
     }
 
   if (!*non_constant_p)