1 files changed, 59 insertions, 0 deletions
diff --git a/gcc/emit-rtl.c b/gcc/emit-rtl.c
index 4564a0b..46fefda 100644
--- a/gcc/emit-rtl.c
+++ b/gcc/emit-rtl.c
@@ -2138,6 +2138,65 @@ widen_memory_access (rtx memref, enum machine_mode mode, HOST_WIDE_INT offset)
   return new_rtx;
 }
 
+/* A fake decl that is used as the MEM_EXPR of spill slots.  */
+static GTY(()) tree spill_slot_decl;
+
+static tree
+get_spill_slot_decl (void)
+{
+  tree d = spill_slot_decl;
+  rtx rd;
+
+  if (d)
+    return d;
+
+  d = build_decl (VAR_DECL, get_identifier ("%sfp"), void_type_node);
+  DECL_ARTIFICIAL (d) = 1;
+  DECL_IGNORED_P (d) = 1;
+  TREE_USED (d) = 1;
+  TREE_THIS_NOTRAP (d) = 1;
+  spill_slot_decl = d;
+
+  rd = gen_rtx_MEM (BLKmode, frame_pointer_rtx);
+  MEM_NOTRAP_P (rd) = 1;
+  MEM_ATTRS (rd) = get_mem_attrs (new_alias_set (), d, const0_rtx,
+				  NULL_RTX, 0, BLKmode);
+  SET_DECL_RTL (d, rd);
+
+  return d;
+}
+
+/* Given MEM, a result from assign_stack_local, fill in the memory
+   attributes as appropriate for a register allocator spill slot.
+   These slots are not aliasable by other memory.  We arrange for
+   them all to use a single MEM_EXPR, so that the aliasing code can
+   work properly in the case of shared spill slots.  */
+
+void
+set_mem_attrs_for_spill (rtx mem)
+{
+  alias_set_type alias;
+  rtx addr, offset;
+  tree expr;
+
+  expr = get_spill_slot_decl ();
+  alias = MEM_ALIAS_SET (DECL_RTL (expr));
+
+  /* We expect the incoming memory to be of the form:
+	(mem:MODE (plus (reg sfp) (const_int offset)))
+     with perhaps the plus missing for offset = 0.  */
+  addr = XEXP (mem, 0);
+  offset = const0_rtx;
+  if (GET_CODE (addr) == PLUS
+      && GET_CODE (XEXP (addr, 1)) == CONST_INT)
+    offset = XEXP (addr, 1);
+
+  MEM_ATTRS (mem) = get_mem_attrs (alias, expr, offset,
+				   MEM_SIZE (mem), MEM_ALIGN (mem),
+				   GET_MODE (mem));
+  MEM_NOTRAP_P (mem) = 1;
+}
+
 /* Return a newly created CODE_LABEL rtx with a unique label number.  */
 
 rtx