From a091e4f5c1a3d1c56ebd0ccf56f09342546170b5 Mon Sep 17 00:00:00 2001 From: amylaar Date: Fri, 23 Jan 2004 13:01:42 +0000 Subject: [PATCH] * doc/tm.texi: Insert some weasel words when LOAD_EXTEND_OP may or may not return non-NIL. * postreload.c (reload_cse_simplify_operands): In LOAD_EXTEND_OP code, check CANNOT_CHANGE_MODE_CLASS git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@76415 138bc75d-0d04-0410-961f-82ee72b054a4 --- gcc/ChangeLog | 7 +++++++ gcc/doc/tm.texi | 21 ++++++++++++++++----- gcc/postreload.c | 9 +++++++++ 3 files changed, 32 insertions(+), 5 deletions(-) diff --git a/gcc/ChangeLog b/gcc/ChangeLog index 0e66702d875..99f3135a6df 100644 --- a/gcc/ChangeLog +++ b/gcc/ChangeLog @@ -1,3 +1,10 @@ +2004-01-23 J"orn Rennecke + + * doc/tm.texi: Insert some weasel words when LOAD_EXTEND_OP + may or may not return non-NIL. + * postreload.c (reload_cse_simplify_operands): In LOAD_EXTEND_OP code, + check CANNOT_CHANGE_MODE_CLASS + 2004-01-23 Jan Hubicka * basic-block.h (PROP_POSTRELOAD): New macro. diff --git a/gcc/doc/tm.texi b/gcc/doc/tm.texi index b3ac4c81cdc..41f1fcb6732 100644 --- a/gcc/doc/tm.texi +++ b/gcc/doc/tm.texi @@ -8520,20 +8520,31 @@ smaller than a word are always performed on the entire register. Most RISC machines have this property and most CISC machines do not. @end defmac -@defmac LOAD_EXTEND_OP (@var{mode}) +@defmac LOAD_EXTEND_OP (@var{mem_mode}) Define this macro to be a C expression indicating when insns that read -memory in @var{mode}, an integral mode narrower than a word, set the -bits outside of @var{mode} to be either the sign-extension or the +memory in @var{mem_mode}, an integral mode narrower than a word, set the +bits outside of @var{mem_mode} to be either the sign-extension or the zero-extension of the data read. Return @code{SIGN_EXTEND} for values -of @var{mode} for which the +of @var{mem_mode} for which the insn sign-extends, @code{ZERO_EXTEND} for which it zero-extends, and @code{NIL} for other modes. -This macro is not called with @var{mode} non-integral or with a width +This macro is not called with @var{mem_mode} non-integral or with a width greater than or equal to @code{BITS_PER_WORD}, so you may return any value in this case. Do not define this macro if it would always return @code{NIL}. On machines where this macro is defined, you will normally define it as the constant @code{SIGN_EXTEND} or @code{ZERO_EXTEND}. + +You may return a non-@code{NIL} value even if for some hard registers +the sign extension is not performed, if for the @code{REGNO_REG_CLASS} +of these hard registers @code{CANNOT_CHANGE_MODE_CLASS} returns nonzero +when the @var{from} mode is @var{mem_mode} and the @var{to} mode is any +integral mode larger than this but not larger than @code{word_mode}. + +You must return @code{NIL} if for some hard registers that allow this +mode, @code{CANNOT_CHANGE_MODE_CLASS} says that they cannot change to +@code{word_mode}, but that they can change to another integral mode that +is larger then @var{mem_mode} but still smaller than @code{word_mode}. @end defmac @defmac SHORT_IMMEDIATES_SIGN_EXTEND diff --git a/gcc/postreload.c b/gcc/postreload.c index 5596d9c2782..6f567f07f9e 100644 --- a/gcc/postreload.c +++ b/gcc/postreload.c @@ -423,6 +423,15 @@ reload_cse_simplify_operands (rtx insn, rtx testreg) || GET_CODE (SET_SRC (set)) == ZERO_EXTEND || GET_CODE (SET_SRC (set)) == SIGN_EXTEND) ; /* Continue ordinary processing. */ +#ifdef CANNOT_CHANGE_MODE_CLASS + /* If the register cannot change mode to word_mode, it follows that + it cannot have been used in word_mode. */ + else if (GET_CODE (SET_DEST (set)) == REG + && CANNOT_CHANGE_MODE_CLASS (GET_MODE (SET_DEST (set)), + word_mode, + REGNO_REG_CLASS (REGNO (SET_DEST (set))))) + ; /* Continue ordinary processing. */ +#endif /* If this is a straight load, make the extension explicit. */ else if (GET_CODE (SET_DEST (set)) == REG && recog_data.n_operands == 2 -- 2.11.4.GIT