From f9c491a6cb3e0b87cf6248ddd01d28a550382b7b Mon Sep 17 00:00:00 2001
From: ebotcazou <ebotcazou@138bc75d-0d04-0410-961f-82ee72b054a4>
Date: Thu, 21 Sep 2017 15:45:36 +0000
Subject: [PATCH] 	* stor-layout.c (bit_from_pos): Do not distribute the
 conversion.

git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@253074 138bc75d-0d04-0410-961f-82ee72b054a4
---
 gcc/ChangeLog                         |  6 ++----
 gcc/stor-layout.c                     | 10 +++-------
 gcc/testsuite/ChangeLog               | 11 +++++++++++
 gcc/testsuite/gnat.dg/discr48.adb     |  9 +++++++++
 gcc/testsuite/gnat.dg/discr48_pkg.ads | 19 +++++++++++++++++++
 5 files changed, 44 insertions(+), 11 deletions(-)
 create mode 100644 gcc/testsuite/gnat.dg/discr48.adb
 create mode 100644 gcc/testsuite/gnat.dg/discr48_pkg.ads

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 4c44002ee12..3071a86c717 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,8 +1,6 @@
-2017-09-21  Tamar Christina  <tamar.christina@arm.com>
+2017-09-21  Eric Botcazou  <ebotcazou@adacore.com>
 
-	PR testsuite/78421
-	* lib/target-supports.exp (check_effective_target_vect_hw_misalign):
-	Invert arm check.
+	* stor-layout.c (bit_from_pos): Do not distribute the conversion.
 
 2017-09-21  Segher Boessenkool  <segher@kernel.crashing.org>
 
diff --git a/gcc/stor-layout.c b/gcc/stor-layout.c
index a6d430760fc..938be6745af 100644
--- a/gcc/stor-layout.c
+++ b/gcc/stor-layout.c
@@ -853,14 +853,10 @@ start_record_layout (tree t)
 tree
 bit_from_pos (tree offset, tree bitpos)
 {
-  if (TREE_CODE (offset) == PLUS_EXPR)
-    offset = size_binop (PLUS_EXPR,
-			 fold_convert (bitsizetype, TREE_OPERAND (offset, 0)),
-			 fold_convert (bitsizetype, TREE_OPERAND (offset, 1)));
-  else
-    offset = fold_convert (bitsizetype, offset);
   return size_binop (PLUS_EXPR, bitpos,
-		     size_binop (MULT_EXPR, offset, bitsize_unit_node));
+		     size_binop (MULT_EXPR,
+				 fold_convert (bitsizetype, offset),
+				 bitsize_unit_node));
 }
 
 /* Return the combined truncated byte position for the byte offset OFFSET and
diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index 1ea22ee833d..ce407c667b5 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,14 @@
+2017-09-21  Eric Botcazou  <ebotcazou@adacore.com>
+
+	* gnat.dg/discr48.adb: New test.
+	* gnat.dg/discr48_pkg.ads: New helper.
+
+2017-09-21  Tamar Christina  <tamar.christina@arm.com>
+
+	PR testsuite/78421
+	* lib/target-supports.exp (check_effective_target_vect_hw_misalign):
+	Invert arm check.
+
 2017-09-21  Cesar Philippidis  <cesar@codesourcery.com>
 
 	* gfortran.dg/goacc/wait.f90: New test.
diff --git a/gcc/testsuite/gnat.dg/discr48.adb b/gcc/testsuite/gnat.dg/discr48.adb
new file mode 100644
index 00000000000..677f6ec67b1
--- /dev/null
+++ b/gcc/testsuite/gnat.dg/discr48.adb
@@ -0,0 +1,9 @@
+-- { dg-do compile }
+
+with Discr48_Pkg; use Discr48_Pkg;
+
+function Discr48 return Rec_Access is
+   C : constant Rec := (Count => 1, Seps => (1 .. 0 => Null_XString));
+begin
+   return new Rec'(C);
+end;
diff --git a/gcc/testsuite/gnat.dg/discr48_pkg.ads b/gcc/testsuite/gnat.dg/discr48_pkg.ads
new file mode 100644
index 00000000000..646b4f11bd3
--- /dev/null
+++ b/gcc/testsuite/gnat.dg/discr48_pkg.ads
@@ -0,0 +1,19 @@
+with Ada.Finalization;
+
+package Discr48_Pkg is
+
+   type XString is new Ada.Finalization.Controlled with record
+      B : Boolean;
+   end record;
+
+   Null_XString : constant XString := (Ada.Finalization.Controlled with B => False);
+
+   type XString_Array is array (Natural range <>) of XString;
+
+   type Rec (Count : Positive) is record
+      Seps : XString_Array (2 .. Count);
+   end record;
+
+   type Rec_Access is access all Rec;
+
+end Discr48_Pkg;
-- 
2.11.4.GIT