Revert:

	2017-03-17  Bernd Schmidt  <bschmidt@redhat.com>

	* combine.c (record_used_regs): New static function.
	(try_combine): Handle situations where there is an additional
	instruction between I2 and I3 which needs to have a LOG_LINK
	updated.

	Revert:
	2017-03-17  Jim Wilson  <jim.wilson@linaro.org>

	* combine.c (try_combine): Delete redundant i1 test.  Call
	prev_nonnote_nondebug_insn instead of prev_nonnote_insn.

From-SVN: r246296

gcc/ChangeLog

+2017-03-20  Segher Boessenkool  <segher@kernel.crashing.org>
+
+	Revert:
+	2017-03-17  Bernd Schmidt  <bschmidt@redhat.com>
+
+	* combine.c (record_used_regs): New static function.
+	(try_combine): Handle situations where there is an additional
+	instruction between I2 and I3 which needs to have a LOG_LINK
+	updated.
+
+	Revert:
+	2017-03-17  Jim Wilson  <jim.wilson@linaro.org>
+
+	* combine.c (try_combine): Delete redundant i1 test.  Call
+	prev_nonnote_nondebug_insn instead of prev_nonnote_insn.
+
 2017-03-20  Aaron Sawdey  <acsawdey@linux.vnet.ibm.com>
 
 	PR target/80083

gcc/combine.c

@@ -2559,57 +2559,6 @@ can_split_parallel_of_n_reg_sets (rtx_insn *insn, int n)
   return true;
 }
 
-/* Set up a set of registers used in an insn.  Called through note_uses,
-   arguments as described for that function.  */
-
-static void
-record_used_regs (rtx *xptr, void *data)
-{
-  bitmap set = (bitmap)data;
-  int i, j;
-  enum rtx_code code;
-  const char *fmt;
-  rtx x = *xptr;
-
-  /* repeat is used to turn tail-recursion into iteration since GCC
-     can't do it when there's no return value.  */
- repeat:
-  if (x == 0)
-    return;
-
-  code = GET_CODE (x);
-  if (REG_P (x))
-    {
-      unsigned regno = REGNO (x);
-      unsigned end_regno = END_REGNO (x);
-      while (regno < end_regno)
-	bitmap_set_bit (set, regno++);
-      return;
-    }
-
-  /* Recursively scan the operands of this expression.  */
-
-  for (i = GET_RTX_LENGTH (code) - 1, fmt = GET_RTX_FORMAT (code); i >= 0; i--)
-    {
-      if (fmt[i] == 'e')
-	{
-	  /* If we are about to do the last recursive call
-	     needed at this level, change it into iteration.
-	     This function is called enough to be worth it.  */
-	  if (i == 0)
-	    {
-	      x = XEXP (x, 0);
-	      goto repeat;
-	    }
-
-	  record_used_regs (&XEXP (x, i), data);
-	}
-      else if (fmt[i] == 'E')
-	for (j = 0; j < XVECLEN (x, i); j++)
-	  record_used_regs (&XVECEXP (x, i, j), data);
-    }
-}
-
 /* Try to combine the insns I0, I1 and I2 into I3.
    Here I0, I1 and I2 appear earlier than I3.
    I0 and I1 can be zero; then we combine just I2 into I3, or I1 and I2 into
@@ -2793,26 +2742,6 @@ try_combine (rtx_insn *i3, rtx_insn *i2, rtx_insn *i1, rtx_insn *i0,
 
   added_links_insn = 0;
 
-  /* For combinations that may result in two insns, we have to gather
-     some extra information about registers used, so that we can
-     update all relevant LOG_LINKS later.  */
-  auto_bitmap i2_regset, i3_regset, links_regset;
-  if (i1)
-    {
-      note_uses (&PATTERN (i2), record_used_regs, (bitmap)i2_regset);
-      note_uses (&PATTERN (i3), record_used_regs, (bitmap)i3_regset);
-      insn_link *ll;
-      FOR_EACH_LOG_LINK (ll, i3)
-	bitmap_set_bit (links_regset, ll->regno);
-      FOR_EACH_LOG_LINK (ll, i2)
-	bitmap_set_bit (links_regset, ll->regno);
-      FOR_EACH_LOG_LINK (ll, i1)
-	bitmap_set_bit (links_regset, ll->regno);
-      if (i0)
-	FOR_EACH_LOG_LINK (ll, i0)
-	  bitmap_set_bit (links_regset, ll->regno);
-    }
-
   /* First check for one important special case that the code below will
      not handle.  Namely, the case where I1 is zero, I2 is a PARALLEL
      and I3 is a SET whose SET_SRC is a SET_DEST in I2.  In that case,
@@ -4122,33 +4051,6 @@ try_combine (rtx_insn *i3, rtx_insn *i2, rtx_insn *i1, rtx_insn *i0,
       return 0;
     }
 
-  auto_bitmap new_regs_in_i2;
-  if (newi2pat)
-    {
-      /* We need to discover situations where we introduce a use of a
-	 register into I2, where none of the existing LOG_LINKS contain
-	 a reference to it.  This can happen if previously I3 referenced
-	 the reg, and there is an additional use between I2 and I3.  We
-	 must remove the LOG_LINKS entry from that additional use and
-	 distribute it along with our own ones.  */
-	note_uses (&newi2pat, record_used_regs, (bitmap)new_regs_in_i2);
-	bitmap_and_compl_into (new_regs_in_i2, i2_regset);
-	bitmap_and_compl_into (new_regs_in_i2, links_regset);
-
-	/* Here, we first look for situations where a hard register use
-	   moved, and just give up.  This should happen approximately
-	   never, and it's not worth it to deal with possibilities like
-	   multi-word registers.  Later, when fixing up LOG_LINKS, we
-	   deal with the case where a pseudo use moved.  */
-	if (!bitmap_empty_p (new_regs_in_i2)
-	    && prev_nonnote_nondebug_insn (i3) != i2
-	    && bitmap_first_set_bit (new_regs_in_i2) < FIRST_PSEUDO_REGISTER)
-	  {
-	    undo_all ();
-	    return 0;
-	  }
-    }
-
   if (MAY_HAVE_DEBUG_INSNS)
     {
       struct undo *undo;
@@ -4591,45 +4493,6 @@ try_combine (rtx_insn *i3, rtx_insn *i2, rtx_insn *i1, rtx_insn *i0,
 			    NULL_RTX, NULL_RTX, NULL_RTX);
       }
 
-    if (newi2pat)
-      {
-	bitmap_iterator iter;
-	unsigned int i;
-
-	/* See comments above where we calculate the bitmap.  */
-	EXECUTE_IF_SET_IN_BITMAP ((bitmap)new_regs_in_i2,
-				  LAST_VIRTUAL_REGISTER, i, iter)
-	  {
-	    rtx reg = regno_reg_rtx[i];
-	    rtx_insn *other;
-	    for (other = NEXT_INSN (i2); other != i3; other = NEXT_INSN (other))
-	      if (NONDEBUG_INSN_P (other)
-		  && (reg_overlap_mentioned_p (reg, PATTERN (other))
-		      || (CALL_P (other) && find_reg_fusage (other, USE, reg))))
-		{
-		  if (dump_file)
-		    fprintf (dump_file,
-			     "found extra use of reg %d at insn %d\n", i,
-			     INSN_UID (other));
-		  insn_link **plink;
-		  for (plink = &LOG_LINKS (other);
-		       *plink;
-		       plink = &(*plink)->next)
-		    {
-		      insn_link *link = *plink;
-		      if (link->regno == i)
-			{
-			  *plink = link->next;
-			  link->next = i3links;
-			  i3links = link;
-			  break;
-			}
-		    }
-		  break;
-		}
-	  }
-      }
-
     distribute_links (i3links);
     distribute_links (i2links);
     distribute_links (i1links);