From: Iain Buclaw <ibuclaw@gdcproject.org>
Date: Tue, 17 Nov 2020 12:11:33 +0000 (+0100)
Subject: d: Fix LHS of array concatentation evaluated before the RHS.
X-Git-Tag: releases/gcc-10.3.0~621
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=bbb887834d78cf6a444bf9cecc29d14b4dfb9cf8;p=thirdparty%2Fgcc.git

d: Fix LHS of array concatentation evaluated before the RHS.

In an array append expression:

    array ~= fun(array);

The array in the left hand side of the expression was extended before
evaluating the result of the right hand side, which resulted in the
newly uninitialized array index being used before set.

This fixes that so that the result of the right hand side is always
saved in a reusable temporary before assigning to the destination.

gcc/d/ChangeLog:

	PR d/97843
	* d-codegen.cc (build_assign): Evaluate TARGET_EXPR before use in
	the right hand side of an assignment.
	* expr.cc (ExprVisitor::visit (CatAssignExp *)): Force a TARGET_EXPR
	on the element to append if it is a CALL_EXPR.

gcc/testsuite/ChangeLog:

	PR d/97843
	* gdc.dg/pr97843.d: New test.

(cherry picked from commit 798bdfa0ebcf2bd012ffce75a594f783a8cb2dd0)
---

diff --git a/gcc/d/d-codegen.cc b/gcc/d/d-codegen.cc
index f57caf226d40..8042f03f369d 100644
--- a/gcc/d/d-codegen.cc
+++ b/gcc/d/d-codegen.cc
@@ -1290,7 +1290,10 @@ build_assign (tree_code code, tree lhs, tree rhs)
 	 since that would cause the LHS to be constructed twice.
 	 So we force the TARGET_EXPR to be expanded without a target.  */
       if (code != INIT_EXPR)
-	rhs = compound_expr (rhs, TARGET_EXPR_SLOT (rhs));
+	{
+	  init = compound_expr (init, rhs);
+	  rhs = TARGET_EXPR_SLOT (rhs);
+	}
       else
 	{
 	  d_mark_addressable (lhs);
diff --git a/gcc/d/expr.cc b/gcc/d/expr.cc
index 9191d3a9510c..acc54f39de39 100644
--- a/gcc/d/expr.cc
+++ b/gcc/d/expr.cc
@@ -884,6 +884,9 @@ public:
 	    tree t2 = build_expr (e->e2);
 	    tree expr = stabilize_expr (&t2);
 
+	    if (TREE_CODE (t2) == CALL_EXPR)
+	      t2 = force_target_expr (t2);
+
 	    result = modify_expr (build_deref (ptrexp), t2);
 
 	    this->result_ = compound_expr (expr, result);
diff --git a/gcc/testsuite/gdc.dg/pr97843.d b/gcc/testsuite/gdc.dg/pr97843.d
new file mode 100644
index 000000000000..29a9d04fa074
--- /dev/null
+++ b/gcc/testsuite/gdc.dg/pr97843.d
@@ -0,0 +1,37 @@
+// https://gcc.gnu.org/bugzilla/show_bug.cgi?id=97843
+// { dg-additional-options "-fmain -funittest" }
+// { dg-do run { target hw } }
+// { dg-skip-if "needs gcc/config.d" { ! d_runtime } }
+
+struct Sdtor
+{
+    int value;
+    ~this() { }
+}
+
+Sdtor sum(Sdtor[] sdtors)
+{
+    int result;
+    foreach (s; sdtors)
+        result += s.value;
+    return Sdtor(result);
+}
+
+uint sum(uint[] ints)
+{
+    uint result;
+    foreach(i; ints)
+        result += i;
+    return result;
+}
+
+unittest
+{
+    Sdtor[] sdtors = [Sdtor(0), Sdtor(1)];
+    sdtors ~= sum(sdtors);
+    assert(sdtors == [Sdtor(0), Sdtor(1), Sdtor(1)]);
+
+    uint[] ints = [0, 1];
+    ints ~= ints.sum;
+    assert(ints == [0, 1, 1]);
+}