* target.h (struct gcc_target): Add mode_rep_extended.

	* rtlanal.c (num_sign_bit_copies_in_rep): New global.
	(init_num_sign_bit_copies_in_rep): Initialize it using
	mode_rep_extended.
	(truncate_to_mode): Use it.
	(init_rtlanal): Call init_num_sign_bit_copies_in_rep.
	* targhooks.h (default_mode_rep_extended): Declare it.
	* targhooks.c (default_mode_rep_extended): Define it.
	* target-def.h (TARGET_MODE_REP_EXTENDED): New macro.  Default to
	default_mode_rep_extended.
	(TARGET_INITIALIZER): Include it.
	* doc/tm.texi (Misc): Document it.
	* config/mips/mips.c (TARGET_TRUNCATED_TO_MODE): Override it.
	(mips_truncated_to_mode): New function.


git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@112998 138bc75d-0d04-0410-961f-82ee72b054a4

1 files changed, 8 insertions, 0 deletions

diff --git a/gcc/target.h b/gcc/target.h
index b9d35782a61..f0287545d7e 100644
--- a/gcc/target.h
+++ b/gcc/target.h
@@ -520,6 +520,14 @@ struct gcc_target
      the reciprocal.  */
   unsigned int (* min_divisions_for_recip_mul) (enum machine_mode mode);
 
+  /* If the representation of integral MODE is such that values are
+     always sign-extended to a wider mode MODE_REP then return
+     SIGN_EXTEND.  Return UNKNOWN otherwise.  */
+  /* Note that the return type ought to be RTX_CODE, but that's not
+     necessarily defined at this point.  */
+  int (* mode_rep_extended) (enum machine_mode mode,
+			     enum machine_mode mode_rep);
+
   /* True if MODE is valid for a pointer in __attribute__((mode("MODE"))).  */
   bool (* valid_pointer_mode) (enum machine_mode mode);