* cselib.c (promote_debug_loc): Allow l->next non-NULL for

	cselib_preserve_constants.
	(cselib_lookup_1): If cselib_preserve_constants,
	a new VALUE is being created for REG and there is a VALUE for the
	same register in wider mode, add another loc with lowpart SUBREG of
	the wider VALUE.
	(cselib_subst_to_values): Handle ENTRY_VALUE.
	* var-tracking.c  (replace_expr_with_values): Return NULL for
	ENTRY_VALUE too.
	* dwarf2out.c (convert_descriptor_to_signed): New function.
	(mem_loc_descriptor) <case ZERO_EXTEND>: Optimize using DW_OP_and
	instead of two shifts.
	(mem_loc_descriptor) <do_shift>: ZERO_EXTEND second argument to
	the right mode if needed.
	(mem_loc_descriptor) <case MOD>: For typed ops just use DW_OP_mod.
	(mem_loc_descriptor) <case UNSIGNED_FIX>: Use
	convert_descriptor_to_signed.
	(mem_loc_descriptor) <case UDIV, CLZ, CTZ, FFS, POPCOUNT, PARITY,
	BSWAP, ROTATE, ROTATERT>: Handle these rtls.

	* gcc.dg/guality/bswaptest.c: New test.
	* gcc.dg/guality/clztest.c: New test.
	* gcc.dg/guality/ctztest.c: New test.
	* gcc.dg/guality/rotatetest.c: New test.


git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@174508 138bc75d-0d04-0410-961f-82ee72b054a4

1 files changed, 44 insertions, 1 deletions

diff --git a/gcc/cselib.c b/gcc/cselib.c
index 56e6d178576..e0697ecfca8 100644
--- a/gcc/cselib.c
+++ b/gcc/cselib.c
@@ -257,7 +257,7 @@ promote_debug_loc (struct elt_loc_list *l)
     {
       n_debug_values--;
       l->setting_insn = cselib_current_insn;
-      gcc_assert (!l->next);
+      gcc_assert (!l->next || cselib_preserve_constants);
     }
 }
 
@@ -1719,6 +1719,12 @@ cselib_subst_to_values (rtx x, enum machine_mode memmode)
 	}
       return e->val_rtx;
 
+    case ENTRY_VALUE:
+      e = cselib_lookup (x, GET_MODE (x), 0, memmode);
+      if (! e)
+	break;
+      return e->val_rtx;
+
     case CONST_DOUBLE:
     case CONST_VECTOR:
     case CONST_INT:
@@ -1843,6 +1849,43 @@ cselib_lookup_1 (rtx x, enum machine_mode mode,
 	  used_regs[n_used_regs++] = i;
 	  REG_VALUES (i) = new_elt_list (REG_VALUES (i), NULL);
 	}
+      else if (cselib_preserve_constants
+	       && GET_MODE_CLASS (mode) == MODE_INT)
+	{
+	  /* During var-tracking, try harder to find equivalences
+	     for SUBREGs.  If a setter sets say a DImode register
+	     and user uses that register only in SImode, add a lowpart
+	     subreg location.  */
+	  struct elt_list *lwider = NULL;
+	  l = REG_VALUES (i);
+	  if (l && l->elt == NULL)
+	    l = l->next;
+	  for (; l; l = l->next)
+	    if (GET_MODE_CLASS (GET_MODE (l->elt->val_rtx)) == MODE_INT
+		&& GET_MODE_SIZE (GET_MODE (l->elt->val_rtx))
+		   > GET_MODE_SIZE (mode)
+		&& (lwider == NULL
+		    || GET_MODE_SIZE (GET_MODE (l->elt->val_rtx))
+		       < GET_MODE_SIZE (GET_MODE (lwider->elt->val_rtx))))
+	      {
+		struct elt_loc_list *el;
+		if (i < FIRST_PSEUDO_REGISTER
+		    && hard_regno_nregs[i][GET_MODE (l->elt->val_rtx)] != 1)
+		  continue;
+		for (el = l->elt->locs; el; el = el->next)
+		  if (!REG_P (el->loc))
+		    break;
+		if (el)
+		  lwider = l;
+	      }
+	  if (lwider)
+	    {
+	      rtx sub = lowpart_subreg (mode, lwider->elt->val_rtx,
+					GET_MODE (lwider->elt->val_rtx));
+	      if (sub)
+		e->locs->next = new_elt_loc_list (e->locs->next, sub);
+	    }
+	}
       REG_VALUES (i)->next = new_elt_list (REG_VALUES (i)->next, e);
       slot = cselib_find_slot (x, e->hash, INSERT, memmode);
       *slot = e;