lower-subreg.c: New file.

gcc/:
	* lower-subreg.c: New file.
	* rtl.def (CONCATN): Define.
	* passes.c (init_optimization_passes): Add pass_lower_subreg and
	pass_lower_subreg2.
	* emit-rtl.c (update_reg_offset): New static function, broken out
	of gen_rtx_REG_offset.
	(gen_rtx_REG_offset): Call update_reg_offset.
	(gen_reg_rtx_offset): New function.
	* regclass.c: Revert patch of 2006-03-05, restoring
	reg_scan_update.
	(clear_reg_info_regno): New function.
	* dwarf2out.c (concatn_loc_descriptor): New static function.
	(loc_descriptor): Handle CONCATN.
	* common.opt (fsplit_wide_types): New option.
	* opts.c (decode_options): Set flag_split_wide_types when
	optimizing.
	* timevar.def (TV_LOWER_SUBREG): Define.
	* rtl.h (gen_reg_rtx_offset): Declare.
	(reg_scan_update): Declare.
	* regs.h (clear_reg_info_regno): Declare.
	* tree-pass.h (pass_lower_subreg): Declare.
	(pass_lower_subreg2): Declare.
	* doc/invoke.texi (Option Summary): List -fno-split-wide-types.
	(Optimize Options): Add -fsplit-wide-types to -O1 list.  Document
	-fsplit-wide-types.
	* doc/rtl.texi (Regs and Memory): Document concat and concatn.
	* Makefile.in (OBJS-common): Add lower-subreg.o.
	(lower-subreg.o): New target.
gcc/testsuite/:
	* gcc.dg/lower-subreg-1.c (test): New test.

From-SVN: r121453

2 files changed, 25 insertions, 1 deletions

diff --git a/gcc/doc/invoke.texi b/gcc/doc/invoke.texi
index 31490b8f687..c7d1c5d187c 100644
--- a/gcc/doc/invoke.texi
+++ b/gcc/doc/invoke.texi
@@ -340,7 +340,7 @@ Objective-C and Objective-C++ Dialects}.
 -fsched2-use-superblocks @gol
 -fsched2-use-traces -fsee -freschedule-modulo-scheduled-loops @gol
 -fsection-anchors  -fsignaling-nans  -fsingle-precision-constant @gol
--fstack-protector  -fstack-protector-all @gol
+-fno-split-wide-types -fstack-protector  -fstack-protector-all @gol
 -fstrict-aliasing  -fstrict-overflow  -ftracer  -fthread-jumps @gol
 -funroll-all-loops  -funroll-loops  -fpeel-loops @gol
 -fsplit-ivs-in-unroller -funswitch-loops @gol
@@ -4600,6 +4600,7 @@ compilation time.
 -fcprop-registers @gol
 -fif-conversion @gol
 -fif-conversion2 @gol
+-fsplit-wide-types @gol
 -ftree-ccp @gol
 -ftree-dce @gol
 -ftree-dominator-opts @gol
@@ -4938,6 +4939,16 @@ the condition is known to be true or false.
 
 Enabled at levels @option{-O2}, @option{-O3}, @option{-Os}.
 
+@item -fsplit-wide-types
+@opindex -fsplit-wide-types
+When using a type that occupies multiple registers, such as @code{long
+long} on a 32-bit system, split the registers apart and allocate them
+independently.  This normally generates better code for those types,
+but may make debugging more difficult.
+
+Enabled at levels @option{-O}, @option{-O2}, @option{-O3},
+@option{-Os}.
+
 @item -fcse-follow-jumps
 @opindex fcse-follow-jumps
 In common subexpression elimination, scan through jump instructions
diff --git a/gcc/doc/rtl.texi b/gcc/doc/rtl.texi
index 2d4644d5873..0498062786f 100644
--- a/gcc/doc/rtl.texi
+++ b/gcc/doc/rtl.texi
@@ -1774,6 +1774,19 @@ is always @code{Pmode}.  If there are any @code{addressof}
 expressions left in the function after CSE, @var{reg} is forced into the
 stack and the @code{addressof} expression is replaced with a @code{plus}
 expression for the address of its stack slot.
+
+@findex concat
+@item (concat@var{m} @var{rtx} @var{rtx})
+This RTX represents the concatenation of two other RTXs.  This is used
+for complex values.  It should only appear in the RTL attached to
+declarations and during RTL generation.  It should not appear in the
+ordinary insn chain.
+
+@findex concatn
+@item (concatn@var{m} [@var{rtx} ...])
+This RTX represents the concatenation of all the @var{rtx} to make a
+single value.  Like @code{concat}, this should only appear in
+declarations, and not in the insn chain.
 @end table
 
 @node Arithmetic