- return (is_gimple_variable (t)
- && is_gimple_reg_type (TREE_TYPE (t))
- /* A volatile decl is not acceptable because we can't reuse it as
- needed. We need to copy it into a temp first. */
- && ! TREE_THIS_VOLATILE (t)
- && ! TREE_ADDRESSABLE (t)
- && ! needs_to_live_in_memory (t));
+ if (!is_gimple_variable (t))
+ return false;
+ if (!is_gimple_reg_type (TREE_TYPE (t)))
+ return false;
+
+ /* A volatile decl is not acceptable because we can't reuse it as
+ needed. We need to copy it into a temp first. */
+ if (TREE_THIS_VOLATILE (t))
+ return false;
+
+ /* We define "registers" as things that can be renamed as needed,
+ which with our infrastructure does not apply to memory. */
+ if (needs_to_live_in_memory (t))
+ return false;
+
+ /* Hard register variables are an interesting case. For those that
+ are call-clobbered, we don't know where all the calls are, since
+ we don't (want to) take into account which operations will turn
+ into libcalls at the rtl level. For those that are call-saved,
+ we don't currently model the fact that calls may in fact change
+ global hard registers, nor do we examine ASM_CLOBBERS at the tree
+ level, and so miss variable changes that might imply. All around,
+ it seems safest to not do too much optimization with these at the
+ tree level at all. We'll have to rely on the rtl optimizers to
+ clean this up, as there we've got all the appropriate bits exposed. */
+ if (TREE_CODE (t) == VAR_DECL && DECL_HARD_REGISTER (t))
+ return false;
+
+ return true;
+}
+
+/* Returns true if T is a GIMPLE formal temporary variable. */
+
+bool
+is_gimple_formal_tmp_var (tree t)
+{
+ if (TREE_CODE (t) == SSA_NAME)
+ return true;
+
+ return TREE_CODE (t) == VAR_DECL && DECL_GIMPLE_FORMAL_TEMP_P (t);
+}
+
+/* Returns true if T is a GIMPLE formal temporary register variable. */
+
+bool
+is_gimple_formal_tmp_reg (tree t)
+{
+ /* The intent of this is to get hold of a value that won't change.
+ An SSA_NAME qualifies no matter if its of a user variable or not. */
+ if (TREE_CODE (t) == SSA_NAME)
+ return true;
+
+ /* We don't know the lifetime characteristics of user variables. */
+ if (!is_gimple_formal_tmp_var (t))
+ return false;
+
+ /* Finally, it must be capable of being placed in a register. */
+ return is_gimple_reg (t);