hooks.h (hook_uint_mode_0): Add Prototype.

* hooks.h (hook_uint_mode_0): Add Prototype.
	* hooks.c (hook_uint_mode_0): New default function.
	* target.def (atomic_align_for_mode): New target hook.
	* tree.c (build_atomic_base): Add alignment override parameter.
	(build_common_tree_nodes): Use atomic alignment override.
	* doc/tm.texi.in (TARGET_ATOMIC_ALIGN_FOR_MODE): Define.
	* doc/tm.texi (TARGET_ATOMIC_ALIGN_FOR_MODE): Add description.

From-SVN: r205273

gcc/ChangeLog

@@ -1,3 +1,13 @@
+2013-11-22 Andrew MacLeod  <amacleod@redhat.com>
+
+	* hooks.h (hook_uint_mode_0): Add Prototype.
+	* hooks.c (hook_uint_mode_0): New default function.
+	* target.def (atomic_align_for_mode): New target hook.
+	* tree.c (build_atomic_base): Add alignment override parameter.
+	(build_common_tree_nodes): Use atomic alignment override.
+	* doc/tm.texi.in (TARGET_ATOMIC_ALIGN_FOR_MODE): Define.
+	* doc/tm.texi (TARGET_ATOMIC_ALIGN_FOR_MODE): Add description.
+
 2013-11-22 Andrew MacLeod  <amacleod@redhat.com>
 
 	* gimple.h: Remove all includes.

gcc/doc/tm.texi

@@ -11500,6 +11500,10 @@ The support includes the assembler, linker and dynamic linker.
 The default value of this hook is based on target's libc.
 @end deftypefn
 
+@deftypefn {Target Hook} {unsigned int} TARGET_ATOMIC_ALIGN_FOR_MODE (enum machine_mode @var{mode})
+If defined, this function returns an appropriate alignment in bits for an atomic object of machine_mode @var{mode}.  If 0 is returned then the default alignment for the specified mode is used. 
+@end deftypefn
+
 @deftypefn {Target Hook} void TARGET_ATOMIC_ASSIGN_EXPAND_FENV (tree *@var{hold}, tree *@var{clear}, tree *@var{update})
 ISO C11 requires atomic compound assignments that may raise floating-point exceptions to raise exceptions corresponding to the arithmetic operation whose result was successfully stored in a compare-and-exchange sequence.  This requires code equivalent to calls to @code{feholdexcept}, @code{feclearexcept} and @code{feupdateenv} to be generated at appropriate points in the compare-and-exchange sequence.  This hook should set @code{*@var{hold}} to an expression equivalent to the call to @code{feholdexcept}, @code{*@var{clear}} to an expression equivalent to the call to @code{feclearexcept} and @code{*@var{update}} to an expression equivalent to the call to @code{feupdateenv}.  The three expressions are @code{NULL_TREE} on entry to the hook and may be left as @code{NULL_TREE} if no code is required in a particular place.  The default implementation leaves all three expressions as @code{NULL_TREE}.  The @code{__atomic_feraiseexcept} function from @code{libatomic} may be of use as part of the code generated in @code{*@var{update}}.
 @end deftypefn

gcc/doc/tm.texi.in

@@ -8407,4 +8407,6 @@ and the associated definitions of those functions.
 
 @hook TARGET_HAS_IFUNC_P
 
+@hook TARGET_ATOMIC_ALIGN_FOR_MODE
+
 @hook TARGET_ATOMIC_ASSIGN_EXPAND_FENV

gcc/hooks.c

@@ -358,6 +358,13 @@ hook_rtx_tree_int_null (tree a ATTRIBUTE_UNUSED, int b ATTRIBUTE_UNUSED)
   return NULL;
 }
 
+/* Generic hook that takes a machine mode and returns an unsigned int 0.  */
+unsigned int
+hook_uint_mode_0 (enum machine_mode m ATTRIBUTE_UNUSED)
+{
+  return 0;
+}
+
 /* Generic hook that takes three trees and returns the last one as is.  */
 tree
 hook_tree_tree_tree_tree_3rd_identity (tree a ATTRIBUTE_UNUSED,

gcc/hooks.h

@@ -92,6 +92,7 @@ extern tree hook_tree_tree_tree_tree_3rd_identity (tree, tree, tree);
 extern tree hook_tree_tree_int_treep_bool_null (tree, int, tree *, bool);
 
 extern unsigned hook_uint_void_0 (void);
+extern unsigned int hook_uint_mode_0 (enum machine_mode);
 
 extern bool default_can_output_mi_thunk_no_vcall (const_tree, HOST_WIDE_INT,
 						  HOST_WIDE_INT, const_tree);

gcc/target.def

@@ -5297,6 +5297,17 @@ DEFHOOKPOD
  @code{bool} @code{true}.",
  unsigned char, 1)
 
+/* Return an unsigned int representing the alignment (in bits) of the atomic
+   type which maps to machine MODE.  This allows alignment to be overridden
+   as needed.  */
+DEFHOOK
+(atomic_align_for_mode,
+"If defined, this function returns an appropriate alignment in bits for an\
+ atomic object of machine_mode @var{mode}.  If 0 is returned then the\
+ default alignment for the specified mode is used. ",
+ unsigned int, (enum machine_mode mode),
+ hook_uint_mode_0)
+
 DEFHOOK
 (atomic_assign_expand_fenv,
 "ISO C11 requires atomic compound assignments that may raise floating-point\

gcc/tree.c

@@ -9550,10 +9550,11 @@ make_or_reuse_accum_type (unsigned size, int unsignedp, int satp)
    during initialization of data types to create the 5 basic atomic
    types. The generic build_variant_type function requires these to
    already be set up in order to function properly, so cannot be
-   called from there.  */
+   called from there.  If ALIGN is non-zero, then ensure alignment is
+   overridden to this value.  */
 
 static tree
-build_atomic_base (tree type)
+build_atomic_base (tree type, unsigned int align)
 {
   tree t;
 
@@ -9564,6 +9565,9 @@ build_atomic_base (tree type)
   t = build_variant_type_copy (type);
   set_type_quals (t, TYPE_QUAL_ATOMIC);
 
+  if (align)
+    TYPE_ALIGN (t) = align;
+
   return t;
 }
 
@@ -9651,14 +9655,21 @@ build_common_tree_nodes (bool signed_char, bool short_double)
 
   /* Don't call build_qualified type for atomics.  That routine does
      special processing for atomics, and until they are initialized
-     it's better not to make that call.  */
-
-  atomicQI_type_node = build_atomic_base (unsigned_intQI_type_node);
-  atomicHI_type_node = build_atomic_base (unsigned_intHI_type_node);
-  atomicSI_type_node = build_atomic_base (unsigned_intSI_type_node);
-  atomicDI_type_node = build_atomic_base (unsigned_intDI_type_node);
-  atomicTI_type_node = build_atomic_base (unsigned_intTI_type_node);
+     it's better not to make that call.
+     
+     Check to see if there is a target override for atomic types.  */
 
+  atomicQI_type_node = build_atomic_base (unsigned_intQI_type_node,
+					targetm.atomic_align_for_mode (QImode));
+  atomicHI_type_node = build_atomic_base (unsigned_intHI_type_node,
+					targetm.atomic_align_for_mode (HImode));
+  atomicSI_type_node = build_atomic_base (unsigned_intSI_type_node,
+					targetm.atomic_align_for_mode (SImode));
+  atomicDI_type_node = build_atomic_base (unsigned_intDI_type_node,
+					targetm.atomic_align_for_mode (DImode));
+  atomicTI_type_node = build_atomic_base (unsigned_intTI_type_node,
+					targetm.atomic_align_for_mode (TImode));
+  	
   access_public_node = get_identifier ("public");
   access_protected_node = get_identifier ("protected");
   access_private_node = get_identifier ("private");