diff --git a/gcc/gimple-ssa-store-merging.c b/gcc/gimple-ssa-store-merging.c
index 6089faf7ac87..17a4250d77f4 100644
--- a/gcc/gimple-ssa-store-merging.c
+++ b/gcc/gimple-ssa-store-merging.c
@@ -1450,6 +1450,7 @@ public:
   bool bit_insertion;
   bool string_concatenation;
   bool only_constants;
+  bool consecutive;
   unsigned int first_nonmergeable_order;
   int lp_nr;
 
@@ -1822,6 +1823,7 @@ merged_store_group::merged_store_group (store_immediate_info *info)
   bit_insertion = info->rhs_code == BIT_INSERT_EXPR;
   string_concatenation = info->rhs_code == STRING_CST;
   only_constants = info->rhs_code == INTEGER_CST;
+  consecutive = true;
   first_nonmergeable_order = ~0U;
   lp_nr = info->lp_nr;
   unsigned HOST_WIDE_INT align_bitpos = 0;
@@ -1957,6 +1959,9 @@ merged_store_group::do_merge (store_immediate_info *info)
       first_stmt = stmt;
     }
 
+  if (info->bitpos != start + width)
+    consecutive = false;
+
   /* We need to use extraction if there is any bit-field.  */
   if (info->rhs_code == BIT_INSERT_EXPR)
     {
@@ -1964,13 +1969,17 @@ merged_store_group::do_merge (store_immediate_info *info)
       gcc_assert (!string_concatenation);
     }
 
-  /* We need to use concatenation if there is any string.  */
+  /* We want to use concatenation if there is any string.  */
   if (info->rhs_code == STRING_CST)
     {
       string_concatenation = true;
       gcc_assert (!bit_insertion);
     }
 
+  /* But we cannot use it if we don't have consecutive stores.  */
+  if (!consecutive)
+    string_concatenation = false;
+
   if (info->rhs_code != INTEGER_CST)
     only_constants = false;
 }
@@ -1982,12 +1991,13 @@ merged_store_group::do_merge (store_immediate_info *info)
 void
 merged_store_group::merge_into (store_immediate_info *info)
 {
+  do_merge (info);
+
   /* Make sure we're inserting in the position we think we're inserting.  */
   gcc_assert (info->bitpos >= start + width
 	      && info->bitregion_start <= bitregion_end);
 
   width = info->bitpos + info->bitsize - start;
-  do_merge (info);
 }
 
 /* Merge a store described by INFO into this merged store.
@@ -1997,11 +2007,11 @@ merged_store_group::merge_into (store_immediate_info *info)
 void
 merged_store_group::merge_overlapping (store_immediate_info *info)
 {
+  do_merge (info);
+
   /* If the store extends the size of the group, extend the width.  */
   if (info->bitpos + info->bitsize > start + width)
     width = info->bitpos + info->bitsize - start;
-
-  do_merge (info);
 }
 
 /* Go through all the recorded stores in this group in program order and
diff --git a/gcc/testsuite/gnat.dg/opt90a.adb b/gcc/testsuite/gnat.dg/opt90a.adb
new file mode 100644
index 000000000000..7de628914ccd
--- /dev/null
+++ b/gcc/testsuite/gnat.dg/opt90a.adb
@@ -0,0 +1,16 @@
+-- { dg-do run }
+-- { dg-options "-O2" }
+
+with Ada.Calendar; use Ada.Calendar;
+with Opt90a_Pkg; use Opt90a_Pkg;
+
+procedure Opt90a is
+  B : constant Integer := Year (Clock);
+  V : Data;
+
+begin
+  V := (R => (A => 0, B => B, C => "000000000000"));
+  if V.R.B /= B then
+    raise Program_Error;
+  end if;
+end;
diff --git a/gcc/testsuite/gnat.dg/opt90a_pkg.ads b/gcc/testsuite/gnat.dg/opt90a_pkg.ads
new file mode 100644
index 000000000000..10a527b8d810
--- /dev/null
+++ b/gcc/testsuite/gnat.dg/opt90a_pkg.ads
@@ -0,0 +1,15 @@
+package Opt90a_Pkg is
+
+  type Rec is record
+    A : Short_Short_Integer;
+    B : Integer;
+    C : String (1 .. 12);
+  end record;
+  pragma Pack (Rec);
+  for Rec'Alignment use 1;
+
+  type Data is tagged record
+    R : Rec;
+  end record;
+
+end Opt90a_Pkg;
diff --git a/gcc/testsuite/gnat.dg/opt90b.adb b/gcc/testsuite/gnat.dg/opt90b.adb
new file mode 100644
index 000000000000..6da58bbcc7ea
--- /dev/null
+++ b/gcc/testsuite/gnat.dg/opt90b.adb
@@ -0,0 +1,16 @@
+-- { dg-do run }
+-- { dg-options "-O2" }
+
+with Ada.Calendar; use Ada.Calendar;
+with Opt90b_Pkg; use Opt90b_Pkg;
+
+procedure Opt90b is
+  B : constant Integer := Year (Clock);
+  V : Data;
+
+begin
+  V := (R => (A => 0, B => B, C => 0, D => "000000000000"));
+  if V.R.B /= B then
+    raise Program_Error;
+  end if;
+end;
diff --git a/gcc/testsuite/gnat.dg/opt90b_pkg.ads b/gcc/testsuite/gnat.dg/opt90b_pkg.ads
new file mode 100644
index 000000000000..f0b233c528e2
--- /dev/null
+++ b/gcc/testsuite/gnat.dg/opt90b_pkg.ads
@@ -0,0 +1,16 @@
+package Opt90b_Pkg is
+
+  type Rec is record
+    A : Short_Short_Integer;
+    B : Integer;
+    C : Short_Integer;
+    D : String (1 .. 12);
+  end record;
+  pragma Pack (Rec);
+  for Rec'Alignment use 1;
+
+  type Data is tagged record
+    R : Rec;
+  end record;
+
+end Opt90b_Pkg;
diff --git a/gcc/testsuite/gnat.dg/opt90c.adb b/gcc/testsuite/gnat.dg/opt90c.adb
new file mode 100644
index 000000000000..b4f4c2790eb8
--- /dev/null
+++ b/gcc/testsuite/gnat.dg/opt90c.adb
@@ -0,0 +1,16 @@
+-- { dg-do run }
+-- { dg-options "-O2" }
+
+with Ada.Calendar; use Ada.Calendar;
+with Opt90c_Pkg; use Opt90c_Pkg;
+
+procedure Opt90c is
+  B : constant Integer := Year (Clock);
+  V : Data;
+
+begin
+  V := (R => (A => 0, B => B, C => 0, D => "000000000000"));
+  if V.R.B /= B then
+    raise Program_Error;
+  end if;
+end;
diff --git a/gcc/testsuite/gnat.dg/opt90c_pkg.ads b/gcc/testsuite/gnat.dg/opt90c_pkg.ads
new file mode 100644
index 000000000000..e772340dc1d2
--- /dev/null
+++ b/gcc/testsuite/gnat.dg/opt90c_pkg.ads
@@ -0,0 +1,16 @@
+package Opt90c_Pkg is
+
+  type Rec is record
+    D : String (1 .. 12);
+    B : Integer;
+    A : Short_Short_Integer;
+    C : Short_Integer;
+  end record;
+  pragma Pack (Rec);
+  for Rec'Alignment use 1;
+
+  type Data is tagged record
+    R : Rec;
+  end record;
+
+end Opt90c_Pkg;
diff --git a/gcc/testsuite/gnat.dg/opt90d.adb b/gcc/testsuite/gnat.dg/opt90d.adb
new file mode 100644
index 000000000000..32ecb68964e9
--- /dev/null
+++ b/gcc/testsuite/gnat.dg/opt90d.adb
@@ -0,0 +1,16 @@
+-- { dg-do run }
+-- { dg-options "-O2" }
+
+with Ada.Calendar; use Ada.Calendar;
+with Opt90d_Pkg; use Opt90d_Pkg;
+
+procedure Opt90d is
+  B : constant Integer := Year (Clock);
+  V : Data;
+
+begin
+  V := (R => (A => 0, B => B, C => 0, D => "000000000000"));
+  if V.R.B /= B then
+    raise Program_Error;
+  end if;
+end;
diff --git a/gcc/testsuite/gnat.dg/opt90d_pkg.ads b/gcc/testsuite/gnat.dg/opt90d_pkg.ads
new file mode 100644
index 000000000000..a68b224893c7
--- /dev/null
+++ b/gcc/testsuite/gnat.dg/opt90d_pkg.ads
@@ -0,0 +1,16 @@
+package Opt90d_Pkg is
+
+  type Rec is record
+    D : String (1 .. 12);
+    C : Short_Integer;
+    A : Short_Short_Integer;
+    B : Integer;
+  end record;
+  pragma Pack (Rec);
+  for Rec'Alignment use 1;
+
+  type Data is tagged record
+    R : Rec;
+  end record;
+
+end Opt90d_Pkg;
diff --git a/gcc/testsuite/gnat.dg/opt90e.adb b/gcc/testsuite/gnat.dg/opt90e.adb
new file mode 100644
index 000000000000..6d62774b6d97
--- /dev/null
+++ b/gcc/testsuite/gnat.dg/opt90e.adb
@@ -0,0 +1,16 @@
+-- { dg-do run }
+-- { dg-options "-O2" }
+
+with Ada.Calendar; use Ada.Calendar;
+with Opt90e_Pkg; use Opt90e_Pkg;
+
+procedure Opt90e is
+  B : constant Integer := Year (Clock);
+  V : Data;
+
+begin
+  V := (R => (A => 0, B => B, C => 0, D => "000000000000"));
+  if V.R.B /= B then
+    raise Program_Error;
+  end if;
+end;
diff --git a/gcc/testsuite/gnat.dg/opt90e_pkg.ads b/gcc/testsuite/gnat.dg/opt90e_pkg.ads
new file mode 100644
index 000000000000..fba16d7a7387
--- /dev/null
+++ b/gcc/testsuite/gnat.dg/opt90e_pkg.ads
@@ -0,0 +1,16 @@
+package Opt90e_Pkg is
+
+  type Rec is record
+    D : String (1 .. 12);
+    A : Short_Short_Integer;
+    B : Integer;
+    C : Short_Integer;
+  end record;
+  pragma Pack (Rec);
+  for Rec'Alignment use 1;
+
+  type Data is tagged record
+    R : Rec;
+  end record;
+
+end Opt90e_Pkg;