gcc/

	* rtl.def (SUBREG): Update comments.
	* rtl.h (reg_attrs): Be explicit about the type of offset used.
	(set_reg_attrs_from_mem): Rename to...
	(set_reg_attrs_from_value): ...this.
	(adjust_reg_mode, byte_lowpart_offset): Declare.
	* emit-rtl.c (byte_lowpart_offset): New function.
	(update_reg_offset): Remove special offset handling for big-endian
	targets.
	(gen_rtx_REG_offset, gen_reg_rtx_offset): Explicitly say that the
	offset parameter is added to REG_OFFSET.
	(adjust_reg_mode): New function.
	(set_reg_attrs_for_mem): Rename to...
	(set_reg_attrs_for_value): ...this and generalize to all values.
	If the register is a lowpart of the value, adjust the offset
	accordingly.
	(set_reg_attrs_for_parm): Update after the above renaming.
	(set_reg_attrs_for_decl_rtl): New function, split out from
	set_decl_incoming_rtl.  Set the offset of plain REGs to the
	offset of the REG's mode from the decl's.  Assert that all
	subregs are lowparts and handle their inner registers in the
	same way as plain REGs.
	(set_decl_rtl, set_incoming_decl_rtl): Use reg_attrs_for_decl_rtl.
	(subreg_lowpart_offset): Explicitly say that the returned offset
	is a SUBREG_BYTE.
	* combine.c (do_SUBST_MODE, try_combine, undo_all): Use adjust_reg_mode
	instead of PUT_MODE.
	* final.c (alter_subreg): Fix/update argument to gen_rtx_REG_offset.
	* config/ia64/ia64.c (ia64_expand_load_address): Likewise.
	* regclass.c (reg_scan_mark_refs): Use set_reg_attrs_from_value.
	* reload.c (find_reloads_subreg_address): Call set_mem_offset
	when offseting a MEM.
	* var-tracking.c (offset_valid_for_tracked_p): Delete.
	(mode_for_reg_attrs): Replace with...
	(track_loc_p): ...this new function.  Return the mode and offset
	to the caller, checking that the latter is valid.  If the rtx is
	a paradoxical lowpart of the decl, use the decl's mode instead.
	Do the same when storing to a register that contains the entire decl.
	(var_lowpart): Use byte_lowpart_offset rather than
	subreg_lowpart_offset when adjusting the offset attribute.
	(count_uses, add_uses, add_stores): Use track_reg_p instead of
	REG_EXPR, MEM_EXPR, REG_OFFSET, INT_MEM_OFFSET, track_expr_p,
	offset_valid_for_tracked_p and mode_for_reg_attrs.  Generate
	lowparts for MEMs as well as REGs.
	(vt_add_function_parameters): When obtaining the information from
	the decl_rtl, adjust the offset to match incoming.  Use track_loc_p
	and var_lowpart.


git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@131055 138bc75d-0d04-0410-961f-82ee72b054a4

1 files changed, 2 insertions, 8 deletions

diff --git a/gcc/rtl.def b/gcc/rtl.def
index 9dee20016e3..fa2238c58b7 100644
--- a/gcc/rtl.def
+++ b/gcc/rtl.def
@@ -371,14 +371,8 @@ DEF_RTL_EXPR(REG, "reg", "i00", RTX_OBJ)
    marked as having one operand so it can be turned into a REG.  */
 DEF_RTL_EXPR(SCRATCH, "scratch", "0", RTX_OBJ)
 
-/* One word of a multi-word value.
-   The first operand is the complete value; the second says which word.
-   The WORDS_BIG_ENDIAN flag controls whether word number 0
-   (as numbered in a SUBREG) is the most or least significant word.
-
-   This is also used to refer to a value in a different machine mode.
-   For example, it can be used to refer to a SImode value as if it were
-   Qimode, or vice versa.  Then the word number is always 0.  */
+/* A reference to a part of another value.  The first operand is the
+   complete value and the second is the byte offset of the selected part.   */
 DEF_RTL_EXPR(SUBREG, "subreg", "ei", RTX_EXTRA)
 
 /* This one-argument rtx is used for move instructions