re PR middle-end/49489 (gcc.c-torture/execute/builtin-bitops-1.c fails on x86_64-linux)

	PR middle-end/49489
	* builtins.c (expand_builtin_unop): Call expand_unop with 0 as
	unsignedp argument instead of 1 for clrsb_optab.
	(fold_builtin_bitop): Fix masking for width > HOST_BITS_PER_WIDE_INT
	and < 2 * HOST_BITS_PER_WIDE_INT.  Optimize BUILT_IN_CLRSB*.
	(fold_builtin_1): Call fold_builtin_binop for BUILT_IN_CLRSB*.
	* optabs.c (widen_leading): Call widen_operand and expand_unop
	with 0 as unsignedp argument instead of 1 for clrsb_optab.
	(expand_unop): Subtract difference of mode sizes also for
	clrsb_optab.

From-SVN: r175265

gcc/ChangeLog

+2011-06-21  Jakub Jelinek  <jakub@redhat.com>
+
+	PR middle-end/49489
+	* builtins.c (expand_builtin_unop): Call expand_unop with 0 as
+	unsignedp argument instead of 1 for clrsb_optab.
+	(fold_builtin_bitop): Fix masking for width > HOST_BITS_PER_WIDE_INT
+	and < 2 * HOST_BITS_PER_WIDE_INT.  Optimize BUILT_IN_CLRSB*.
+	(fold_builtin_1): Call fold_builtin_binop for BUILT_IN_CLRSB*.
+	* optabs.c (widen_leading): Call widen_operand and expand_unop
+	with 0 as unsignedp argument instead of 1 for clrsb_optab.
+	(expand_unop): Subtract difference of mode sizes also for
+	clrsb_optab.
+
 2011-06-21  Georg-Johann Lay  <avr@gjlay.de>
 
 	* config/avr/avr.md (*jcindirect_jump): Fix build warning.

gcc/builtins.c

@@ -4578,7 +4578,7 @@ expand_builtin_unop (enum machine_mode target_mode, tree exp, rtx target,
   /* Compute op, into TARGET if possible.
      Set TARGET to wherever the result comes back.  */
   target = expand_unop (TYPE_MODE (TREE_TYPE (CALL_EXPR_ARG (exp, 0))),
-			op_optab, op0, target, 1);
+			op_optab, op0, target, op_optab != clrsb_optab);
   gcc_assert (target);
 
   return convert_to_mode (target_mode, target, 0);
@@ -7265,7 +7265,8 @@ fold_builtin_bitop (tree fndecl, tree arg)
 	{
 	  hi = TREE_INT_CST_HIGH (arg);
 	  if (width < 2 * HOST_BITS_PER_WIDE_INT)
-	    hi &= ~((HOST_WIDE_INT) (-1) >> (width - HOST_BITS_PER_WIDE_INT));
+	    hi &= ~((unsigned HOST_WIDE_INT) (-1)
+		    << (width - HOST_BITS_PER_WIDE_INT));
 	}
       else
 	{
@@ -7303,6 +7304,26 @@ fold_builtin_bitop (tree fndecl, tree arg)
 	    result = width;
 	  break;
 
+	CASE_INT_FN (BUILT_IN_CLRSB):
+	  if (width > HOST_BITS_PER_WIDE_INT
+	      && (hi & ((unsigned HOST_WIDE_INT) 1
+			<< (width - HOST_BITS_PER_WIDE_INT - 1))) != 0)
+	    {
+	      hi = ~hi & ~((unsigned HOST_WIDE_INT) (-1)
+			   << (width - HOST_BITS_PER_WIDE_INT - 1));
+	      lo = ~lo;
+	    }
+	  else if (width <= HOST_BITS_PER_WIDE_INT
+		   && (lo & ((unsigned HOST_WIDE_INT) 1 << (width - 1))) != 0)
+	    lo = ~lo & ~((unsigned HOST_WIDE_INT) (-1) << (width - 1));
+	  if (hi != 0)
+	    result = width - floor_log2 (hi) - 2 - HOST_BITS_PER_WIDE_INT;
+	  else if (lo != 0)
+	    result = width - floor_log2 (lo) - 2;
+	  else
+	    result = width - 1;
+	  break;
+
 	CASE_INT_FN (BUILT_IN_POPCOUNT):
 	  result = 0;
 	  while (lo)
@@ -9737,6 +9758,7 @@ fold_builtin_1 (location_t loc, tree fndecl, tree arg0, bool ignore)
     CASE_INT_FN (BUILT_IN_FFS):
     CASE_INT_FN (BUILT_IN_CLZ):
     CASE_INT_FN (BUILT_IN_CTZ):
+    CASE_INT_FN (BUILT_IN_CLRSB):
     CASE_INT_FN (BUILT_IN_POPCOUNT):
     CASE_INT_FN (BUILT_IN_PARITY):
       return fold_builtin_bitop (fndecl, arg0);

gcc/optabs.c

 /* Expand the basic unary and binary arithmetic operations, for GNU compiler.
    Copyright (C) 1987, 1988, 1992, 1993, 1994, 1995, 1996, 1997, 1998,
-   1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010
-   Free Software Foundation, Inc.
+   1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010,
+   2011  Free Software Foundation, Inc.
 
 This file is part of GCC.
 
@@ -2350,8 +2350,10 @@ widen_leading (enum machine_mode mode, rtx op0, rtx target, optab unoptab)
 
 	      if (target == 0)
 		target = gen_reg_rtx (mode);
-	      xop0 = widen_operand (op0, wider_mode, mode, true, false);
-	      temp = expand_unop (wider_mode, unoptab, xop0, NULL_RTX, true);
+	      xop0 = widen_operand (op0, wider_mode, mode,
+				    unoptab != clrsb_optab, false);
+	      temp = expand_unop (wider_mode, unoptab, xop0, NULL_RTX,
+				  unoptab != clrsb_optab);
 	      if (temp != 0)
 		temp = expand_binop (wider_mode, sub_optab, temp,
 				     GEN_INT (GET_MODE_BITSIZE (wider_mode)
@@ -3075,8 +3077,9 @@ expand_unop (enum machine_mode mode, optab unoptab, rtx op0, rtx target,
 				  unsignedp);
 
 	      /* If we are generating clz using wider mode, adjust the
-		 result.  */
-	      if (unoptab == clz_optab && temp != 0)
+		 result.  Similarly for clrsb.  */
+	      if ((unoptab == clz_optab || unoptab == clrsb_optab)
+		  && temp != 0)
 		temp = expand_binop (wider_mode, sub_optab, temp,
 				     GEN_INT (GET_MODE_BITSIZE (wider_mode)
 					      - GET_MODE_BITSIZE (mode)),