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

1 files changed, 64 insertions, 18 deletions

diff --git a/gcc/regclass.c b/gcc/regclass.c
index 7726ea1..0a1114d 100644
--- a/gcc/regclass.c
+++ b/gcc/regclass.c
@@ -1,6 +1,6 @@
 /* Compute register class preferences for pseudo-registers.
    Copyright (C) 1987, 1988, 1991, 1992, 1993, 1994, 1995, 1996
-   1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005
+   1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007
    Free Software Foundation, Inc.
 
 This file is part of GCC.
@@ -859,7 +859,7 @@ static void record_address_regs (enum machine_mode, rtx, int, enum rtx_code,
 #ifdef FORBIDDEN_INC_DEC_CLASSES
 static int auto_inc_dec_reg_p (rtx, enum machine_mode);
 #endif
-static void reg_scan_mark_refs (rtx, rtx, int);
+static void reg_scan_mark_refs (rtx, rtx, int, unsigned int);
 
 /* Wrapper around REGNO_OK_FOR_INDEX_P, to allow pseudo registers.  */
 
@@ -2292,6 +2292,14 @@ free_reg_info (void)
   regno_allocated = 0;
   reg_n_max = 0;
 }
+
+/* Clear the information stored for REGNO.  */
+void
+clear_reg_info_regno (unsigned int regno)
+{
+  if (regno < regno_allocated)
+    memset (VEC_index (reg_info_p, reg_n_info, regno), 0, sizeof (reg_info));
+}
 
 /* This is the `regscan' pass of the compiler, run just before cse
    and again just before loop.
@@ -2333,10 +2341,10 @@ reg_scan (rtx f, unsigned int nregs)
 	if (GET_CODE (pat) == PARALLEL
 	    && XVECLEN (pat, 0) > max_parallel)
 	  max_parallel = XVECLEN (pat, 0);
-	reg_scan_mark_refs (pat, insn, 0);
+	reg_scan_mark_refs (pat, insn, 0, 0);
 
 	if (REG_NOTES (insn))
-	  reg_scan_mark_refs (REG_NOTES (insn), insn, 1);
+	  reg_scan_mark_refs (REG_NOTES (insn), insn, 1, 0);
       }
 
   max_parallel += max_set_parallel;
@@ -2344,11 +2352,39 @@ reg_scan (rtx f, unsigned int nregs)
   timevar_pop (TV_REG_SCAN);
 }
 
+/* Update 'regscan' information by looking at the insns
+   from FIRST to LAST.  Some new REGs have been created,
+   and any REG with number greater than OLD_MAX_REGNO is
+   such a REG.  We only update information for those.  */
+
+void
+reg_scan_update (rtx first, rtx last, unsigned int old_max_regno)
+{
+  rtx insn;
+
+  allocate_reg_info (max_reg_num (), FALSE, FALSE);
+
+  for (insn = first; insn != last; insn = NEXT_INSN (insn))
+    if (INSN_P (insn))
+      {
+	rtx pat = PATTERN (insn);
+	if (GET_CODE (pat) == PARALLEL
+	    && XVECLEN (pat, 0) > max_parallel)
+	  max_parallel = XVECLEN (pat, 0);
+	reg_scan_mark_refs (pat, insn, 0, old_max_regno);
+
+	if (REG_NOTES (insn))
+	  reg_scan_mark_refs (REG_NOTES (insn), insn, 1, old_max_regno);
+      }
+}
+
 /* X is the expression to scan.  INSN is the insn it appears in.
-   NOTE_FLAG is nonzero if X is from INSN's notes rather than its body.  */
+   NOTE_FLAG is nonzero if X is from INSN's notes rather than its body.
+   We should only record information for REGs with numbers
+   greater than or equal to MIN_REGNO.  */
 
 static void
-reg_scan_mark_refs (rtx x, rtx insn, int note_flag)
+reg_scan_mark_refs (rtx x, rtx insn, int note_flag, unsigned int min_regno)
 {
   enum rtx_code code;
   rtx dest;
@@ -2375,35 +2411,43 @@ reg_scan_mark_refs (rtx x, rtx insn, int note_flag)
       {
 	unsigned int regno = REGNO (x);
 
-	if (!note_flag)
-	  REGNO_LAST_UID (regno) = INSN_UID (insn);
-	if (REGNO_FIRST_UID (regno) == 0)
-	  REGNO_FIRST_UID (regno) = INSN_UID (insn);
+	if (regno >= min_regno)
+	  {
+	    if (!note_flag)
+	      REGNO_LAST_UID (regno) = INSN_UID (insn);
+	    if (REGNO_FIRST_UID (regno) == 0)
+	      REGNO_FIRST_UID (regno) = INSN_UID (insn);
+	    /* If we are called by reg_scan_update() (indicated by min_regno
+	       being set), we also need to update the reference count.  */
+	    if (min_regno)
+	      REG_N_REFS (regno)++;
+	  }
       }
       break;
 
     case EXPR_LIST:
       if (XEXP (x, 0))
-	reg_scan_mark_refs (XEXP (x, 0), insn, note_flag);
+	reg_scan_mark_refs (XEXP (x, 0), insn, note_flag, min_regno);
       if (XEXP (x, 1))
-	reg_scan_mark_refs (XEXP (x, 1), insn, note_flag);
+	reg_scan_mark_refs (XEXP (x, 1), insn, note_flag, min_regno);
       break;
 
     case INSN_LIST:
       if (XEXP (x, 1))
-	reg_scan_mark_refs (XEXP (x, 1), insn, note_flag);
+	reg_scan_mark_refs (XEXP (x, 1), insn, note_flag, min_regno);
       break;
 
     case CLOBBER:
       {
 	rtx reg = XEXP (x, 0);
-	if (REG_P (reg))
+	if (REG_P (reg)
+	    && REGNO (reg) >= min_regno)
 	  {
 	    REG_N_SETS (REGNO (reg))++;
 	    REG_N_REFS (REGNO (reg))++;
 	  }
 	else if (MEM_P (reg))
-	  reg_scan_mark_refs (XEXP (reg, 0), insn, note_flag);
+	  reg_scan_mark_refs (XEXP (reg, 0), insn, note_flag, min_regno);
       }
       break;
 
@@ -2420,7 +2464,8 @@ reg_scan_mark_refs (rtx x, rtx insn, int note_flag)
       if (GET_CODE (dest) == PARALLEL)
 	max_set_parallel = MAX (max_set_parallel, XVECLEN (dest, 0) - 1);
 
-      if (REG_P (dest))
+      if (REG_P (dest)
+	  && REGNO (dest) >= min_regno)
 	{
 	  REG_N_SETS (REGNO (dest))++;
 	  REG_N_REFS (REGNO (dest))++;
@@ -2440,6 +2485,7 @@ reg_scan_mark_refs (rtx x, rtx insn, int note_flag)
 
       if (REG_P (SET_DEST (x))
 	  && REGNO (SET_DEST (x)) >= FIRST_PSEUDO_REGISTER
+	  && REGNO (SET_DEST (x)) >= min_regno
 	  /* If the destination pseudo is set more than once, then other
 	     sets might not be to a pointer value (consider access to a
 	     union in two threads of control in the presence of global
@@ -2500,12 +2546,12 @@ reg_scan_mark_refs (rtx x, rtx insn, int note_flag)
 	for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--)
 	  {
 	    if (fmt[i] == 'e')
-	      reg_scan_mark_refs (XEXP (x, i), insn, note_flag);
+	      reg_scan_mark_refs (XEXP (x, i), insn, note_flag, min_regno);
 	    else if (fmt[i] == 'E' && XVEC (x, i) != 0)
 	      {
 		int j;
 		for (j = XVECLEN (x, i) - 1; j >= 0; j--)
-		  reg_scan_mark_refs (XVECEXP (x, i, j), insn, note_flag);
+		  reg_scan_mark_refs (XVECEXP (x, i, j), insn, note_flag, min_regno);
 	      }
 	  }
       }