2006-01-27 Daniel Berlin <dberlin@dberlin.org>

	    Kenneth Zadeck <zadeck@naturalbridge.com>

	PR rtl-optimization/24762 
	* doc/tm.texi: Added TARGET_EXTRA_LIVE_ON_ENTRY.
	* targhooks.c (hook_void_bitmap): New hook prototype.
	* targhoohs.h (hook_void_bitmap): Ditto.
	* bitmap.h (bitmap_head_def): Moved to coretypes.h.
	* coretypes.h (bitmap_head_def): Moved from bitmap.h.
	* target.h (live_on_entry): New function pointer.
	* df-scan.c (df_all_hard_regs): Removed.
	(df_scan_dump, df_hard_reg_init): Removed df_all_hard_regs.
	(df_scan_free_internal): Added df->entry_block_defs.
	(df_scan_alloc): Ditto.
	(df_scan_dump): Ditto.
	(df_uses_record): Plumbed flag field properly thru calls.
	Record EH_RETURN_DATA_REGNO in eh blocks unconditionally.
	This part fixes PR24762.
	(df_bb_refs_record): Added code to make the frame and arg
	pointers live in EH blocks.
	(df_refs_record): Added call to df_record_entry_block_defs.
	(df_record_entry_block_defs): New function.
	* df-core.c: Added comments to describe new artifical defs.
	* df.h (DF_REF_DIES_AFTER_THIS_USE): New flag in enum df_ref_flags.
	(entry_block_defs): New field in struct df.
	(df_all_hard_regs): Deleted.
	* target-def.h: Added TARGET_EXTRA_LIVE_ON_ENTRY.
	* df-problems.c (df_ru_bb_local_compute_process_def):
	Added code to handle artifical defs in the entry to a function.
	(df_ru_bb_local_compute): Ditto.
	(df_rd_bb_local_compute_process_def):  Ditto.
	(df_rd_bb_local_compute): Ditto.
	(df_lr_bb_local_compute): Ditto.
	(df_ur_bb_local_compute): Ditto.
	(df_urec_bb_local_compute):  Ditto.
	(df_chain_create_bb):  Ditto.
	(df_ur_local_finalize):	Removed entry.
	(df_urec_init): Ditto.
	(df_urec_local_finalize): Ditto.
	(df_ri_bb_compute): Added detection of last use of pseudos.
	* Makefile.in (df-scan.o): Updated dependencies.
	* config/mips/mips-protos.h (mips_set_live_on_entry): Added.
	* config/mips/mips.c (mips_set_live_on_entry): Added.
	* config/mips/mips.c (TARGET_EXTRA_LIVE_ON_ENTRY): Added value
	for target hook.
	* dce.c (marked_insn_p): Added code to handle artifical defs.



git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@110312 138bc75d-0d04-0410-961f-82ee72b054a4

1 files changed, 17 insertions, 12 deletions

diff --git a/gcc/df-core.c b/gcc/df-core.c
index a0ed23caa16..416406b68f1 100644
--- a/gcc/df-core.c
+++ b/gcc/df-core.c
@@ -205,18 +205,23 @@ There are 4 ways to obtain access to refs:
    defs and uses are only there if DF_HARD_REGS was specified when the
    df instance was created.
  
-   Artificial defs and uses occur at the beginning blocks that are the
-   destination of eh edges.  The defs come from the registers
-   specified in EH_RETURN_DATA_REGNO and the uses come from the
-   registers specified in ED_USES.  Logically these defs and uses
-   should really occur along the eh edge, but there is no convienent
-   way to do this.  Artificial edges that occur at the beginning of
-   the block have the DF_REF_AT_TOP flag set.
-   
-   Artificial uses also occur at the end of all blocks.  These arise
-   from the hard registers that are always live, such as the stack
-   register and are put there to keep the code from forgetting about
-   them.
+   Artificial defs and uses occur both at the beginning and ends of blocks.
+
+     For blocks that area at the destination of eh edges, the
+     artificial uses and defs occur at the beginning.  The defs relate
+     to the registers specified in EH_RETURN_DATA_REGNO and the uses
+     relate to the registers specified in ED_USES.  Logically these
+     defs and uses should really occur along the eh edge, but there is
+     no convenient way to do this.  Artificial edges that occur at the
+     beginning of the block have the DF_REF_AT_TOP flag set.
+
+     Artificial uses occur at the end of all blocks.  These arise from
+     the hard registers that are always live, such as the stack
+     register and are put there to keep the code from forgetting about
+     them.
+
+     Artifical defs occur at the end of the entry block.  These arise
+     from registers that are live at entry to the function.
 
 2) All of the uses and defs associated with each pseudo or hard
    register are linked in a bidirectional chain.  These are called