From: Eric Botcazou <ebotcazou@adacore.com>
Date: Tue, 26 Feb 2019 08:12:21 +0000 (+0000)
Subject: re PR ada/81956 (call to null procedure not optimized away)
X-Git-Tag: releases/gcc-7.5.0~570
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=de4e663d340b3f67be660ff652770a632673f314;p=thirdparty%2Fgcc.git

re PR ada/81956 (call to null procedure not optimized away)

	PR ada/81956
	Backport from mainline
	2017-09-06  Ed Schonberg  <schonberg@adacore.com>

	* exp_ch6.adb (Expand_Call_Helper): Do not optimize calls to
	null procedures when GNAT coverage is used, so that their (empty)
	bodies are properly covered.

	2017-09-06  Ed Schonberg  <schonberg@adacore.com>

	* exp_ch6.adb (Expand_Call_Helper): Replace call to null
	procedure by a single null statement, after evaluating the
	actuals that require it.

From-SVN: r269205
---

diff --git a/gcc/ada/ChangeLog b/gcc/ada/ChangeLog
index ee33d9fb21e6..8e4ab2167617 100644
--- a/gcc/ada/ChangeLog
+++ b/gcc/ada/ChangeLog
@@ -1,3 +1,19 @@
+2019-02-26  Eric Botcazou  <ebotcazou@adacore.com>
+
+	PR ada/81956
+	Backport from mainline
+	2017-09-06  Ed Schonberg  <schonberg@adacore.com>
+
+	* exp_ch6.adb (Expand_Call_Helper): Do not optimize calls to
+	null procedures when GNAT coverage is used, so that their (empty)
+	bodies are properly covered.
+
+	2017-09-06  Ed Schonberg  <schonberg@adacore.com>
+
+	* exp_ch6.adb (Expand_Call_Helper): Replace call to null
+	procedure by a single null statement, after evaluating the
+	actuals that require it.
+
 2019-02-23  Eric Botcazou  <ebotcazou@adacore.com>
 
 	PR ada/89349
diff --git a/gcc/ada/exp_ch6.adb b/gcc/ada/exp_ch6.adb
index e9f13319ed51..1713581f3c55 100644
--- a/gcc/ada/exp_ch6.adb
+++ b/gcc/ada/exp_ch6.adb
@@ -3937,6 +3937,23 @@ package body Exp_Ch6 is
               Unchecked_Convert_To
                 (RTE (RE_Address), Relocate_Node (First_Actual (Call_Node))));
             return;
+
+         --  A call to a null procedure is replaced by a null statement, but we
+         --  are not allowed to ignore possible side effects of the call, so we
+         --  make sure that actuals are evaluated.
+         --  We also suppress this optimization for GNATCoverage.
+
+         elsif Is_Null_Procedure (Subp)
+           and then not Opt.Suppress_Control_Flow_Optimizations
+         then
+            Actual := First_Actual (Call_Node);
+            while Present (Actual) loop
+               Remove_Side_Effects (Actual);
+               Next_Actual (Actual);
+            end loop;
+
+            Rewrite (Call_Node, Make_Null_Statement (Loc));
+            return;
          end if;
 
          --  Handle inlining. No action needed if the subprogram is not inlined