re PR target/29776 (result of ffs/clz/ctz/popcount/parity are already sign-extended)

	PR target/29776
	* fold-const.c (tree_call_nonnegative_warnv_p): Return true
	for BUILT_IN_C{LZ,LRSB}*.
	* tree.h (CASE_INT_FN): Add FN##IMAX case.
	* tree-vrp.c (extract_range_basic): Handle
	BUILT_IN_{FFS,PARITY,POPCOUNT,C{LZ,TZ,LRSB}}*.  For
	BUILT_IN_CONSTANT_P if argument isn't (D) of PARM_DECL,
	fall thru to code calling set_value*.
	* builtins.c (expand_builtin): Remove *IMAX cases.
	(fold_builtin_bitop): For BUILT_IN_CLRSB* return NULL_TREE
	if width is bigger than 2*HWI.

	* libgcc2.c (__floattisf): Avoid undefined signed overflow.

	* gcc.dg/tree-ssa/vrp89.c: New test.

From-SVN: r200731

1 files changed, 178 insertions, 14 deletions

diff --git a/gcc/tree-vrp.c b/gcc/tree-vrp.c
index ec7ef8f..ca9d8bd 100644
--- a/gcc/tree-vrp.c
+++ b/gcc/tree-vrp.c
@@ -3565,20 +3565,184 @@ extract_range_basic (value_range_t *vr, gimple stmt)
   bool sop = false;
   tree type = gimple_expr_type (stmt);
 
-  /* If the call is __builtin_constant_p and the argument is a
-     function parameter resolve it to false.  This avoids bogus
-     array bound warnings.
-     ???  We could do this as early as inlining is finished.  */
-  if (gimple_call_builtin_p (stmt, BUILT_IN_CONSTANT_P))
-    {
-      tree arg = gimple_call_arg (stmt, 0);
-      if (TREE_CODE (arg) == SSA_NAME
-	  && SSA_NAME_IS_DEFAULT_DEF (arg)
-	  && TREE_CODE (SSA_NAME_VAR (arg)) == PARM_DECL)
-	set_value_range_to_null (vr, type);
-    }
-  else if (INTEGRAL_TYPE_P (type)
-	   && gimple_stmt_nonnegative_warnv_p (stmt, &sop))
+  if (gimple_call_builtin_p (stmt, BUILT_IN_NORMAL))
+    {
+      tree fndecl = gimple_call_fndecl (stmt), arg;
+      int mini, maxi, zerov = 0, prec;
+
+      switch (DECL_FUNCTION_CODE (fndecl))
+	{
+	case BUILT_IN_CONSTANT_P:
+	  /* If the call is __builtin_constant_p and the argument is a
+	     function parameter resolve it to false.  This avoids bogus
+	     array bound warnings.
+	     ???  We could do this as early as inlining is finished.  */
+	  arg = gimple_call_arg (stmt, 0);
+	  if (TREE_CODE (arg) == SSA_NAME
+	      && SSA_NAME_IS_DEFAULT_DEF (arg)
+	      && TREE_CODE (SSA_NAME_VAR (arg)) == PARM_DECL)
+	    {
+	      set_value_range_to_null (vr, type);
+	      return;
+	    }
+	  break;
+	  /* Both __builtin_ffs* and __builtin_popcount return
+	     [0, prec].  */
+	CASE_INT_FN (BUILT_IN_FFS):
+	CASE_INT_FN (BUILT_IN_POPCOUNT):
+	  arg = gimple_call_arg (stmt, 0);
+	  prec = TYPE_PRECISION (TREE_TYPE (arg));
+	  mini = 0;
+	  maxi = prec;
+	  if (TREE_CODE (arg) == SSA_NAME)
+	    {
+	      value_range_t *vr0 = get_value_range (arg);
+	      /* If arg is non-zero, then ffs or popcount
+		 are non-zero.  */
+	      if (((vr0->type == VR_RANGE
+		    && integer_nonzerop (vr0->min))
+		   || (vr0->type == VR_ANTI_RANGE
+		       && integer_zerop (vr0->min)))
+		  && !TREE_OVERFLOW (vr0->min))
+		mini = 1;
+	      /* If some high bits are known to be zero,
+		 we can decrease the maximum.  */
+	      if (vr0->type == VR_RANGE
+		  && TREE_CODE (vr0->max) == INTEGER_CST
+		  && !TREE_OVERFLOW (vr0->max))
+		maxi = tree_floor_log2 (vr0->max) + 1;
+	    }
+	  goto bitop_builtin;
+	  /* __builtin_parity* returns [0, 1].  */
+	CASE_INT_FN (BUILT_IN_PARITY):
+	  mini = 0;
+	  maxi = 1;
+	  goto bitop_builtin;
+	  /* __builtin_c[lt]z* return [0, prec-1], except for
+	     when the argument is 0, but that is undefined behavior.
+	     On many targets where the CLZ RTL or optab value is defined
+	     for 0 the value is prec, so include that in the range
+	     by default.  */
+	CASE_INT_FN (BUILT_IN_CLZ):
+	  arg = gimple_call_arg (stmt, 0);
+	  prec = TYPE_PRECISION (TREE_TYPE (arg));
+	  mini = 0;
+	  maxi = prec;
+	  if (optab_handler (clz_optab, TYPE_MODE (TREE_TYPE (arg)))
+	      != CODE_FOR_nothing
+	      && CLZ_DEFINED_VALUE_AT_ZERO (TYPE_MODE (TREE_TYPE (arg)),
+					    zerov)
+	      /* Handle only the single common value.  */
+	      && zerov != prec)
+	    /* Magic value to give up, unless vr0 proves
+	       arg is non-zero.  */
+	    mini = -2;
+	  if (TREE_CODE (arg) == SSA_NAME)
+	    {
+	      value_range_t *vr0 = get_value_range (arg);
+	      /* From clz of VR_RANGE minimum we can compute
+		 result maximum.  */
+	      if (vr0->type == VR_RANGE
+		  && TREE_CODE (vr0->min) == INTEGER_CST
+		  && !TREE_OVERFLOW (vr0->min))
+		{
+		  maxi = prec - 1 - tree_floor_log2 (vr0->min);
+		  if (maxi != prec)
+		    mini = 0;
+		}
+	      else if (vr0->type == VR_ANTI_RANGE
+		       && integer_zerop (vr0->min)
+		       && !TREE_OVERFLOW (vr0->min))
+		{
+		  maxi = prec - 1;
+		  mini = 0;
+		}
+	      if (mini == -2)
+		break;
+	      /* From clz of VR_RANGE maximum we can compute
+		 result minimum.  */
+	      if (vr0->type == VR_RANGE
+		  && TREE_CODE (vr0->max) == INTEGER_CST
+		  && !TREE_OVERFLOW (vr0->max))
+		{
+		  mini = prec - 1 - tree_floor_log2 (vr0->max);
+		  if (mini == prec)
+		    break;
+		}
+	    }
+	  if (mini == -2)
+	    break;
+	  goto bitop_builtin;
+	  /* __builtin_ctz* return [0, prec-1], except for
+	     when the argument is 0, but that is undefined behavior.
+	     If there is a ctz optab for this mode and
+	     CTZ_DEFINED_VALUE_AT_ZERO, include that in the range,
+	     otherwise just assume 0 won't be seen.  */
+	CASE_INT_FN (BUILT_IN_CTZ):
+	  arg = gimple_call_arg (stmt, 0);
+	  prec = TYPE_PRECISION (TREE_TYPE (arg));
+	  mini = 0;
+	  maxi = prec - 1;
+	  if (optab_handler (ctz_optab, TYPE_MODE (TREE_TYPE (arg)))
+	      != CODE_FOR_nothing
+	      && CTZ_DEFINED_VALUE_AT_ZERO (TYPE_MODE (TREE_TYPE (arg)),
+					    zerov))
+	    {
+	      /* Handle only the two common values.  */
+	      if (zerov == -1)
+		mini = -1;
+	      else if (zerov == prec)
+		maxi = prec;
+	      else
+		/* Magic value to give up, unless vr0 proves
+		   arg is non-zero.  */
+		mini = -2;
+	    }
+	  if (TREE_CODE (arg) == SSA_NAME)
+	    {
+	      value_range_t *vr0 = get_value_range (arg);
+	      /* If arg is non-zero, then use [0, prec - 1].  */
+	      if (((vr0->type == VR_RANGE
+		    && integer_nonzerop (vr0->min))
+		   || (vr0->type == VR_ANTI_RANGE
+		       && integer_zerop (vr0->min)))
+		  && !TREE_OVERFLOW (vr0->min))
+		{
+		  mini = 0;
+		  maxi = prec - 1;
+		}
+	      /* If some high bits are known to be zero,
+		 we can decrease the result maximum.  */
+	      if (vr0->type == VR_RANGE
+		  && TREE_CODE (vr0->max) == INTEGER_CST
+		  && !TREE_OVERFLOW (vr0->max))
+		{
+		  maxi = tree_floor_log2 (vr0->max);
+		  /* For vr0 [0, 0] give up.  */
+		  if (maxi == -1)
+		    break;
+		}
+	    }
+	  if (mini == -2)
+	    break;
+	  goto bitop_builtin;
+	  /* __builtin_clrsb* returns [0, prec-1].  */
+	CASE_INT_FN (BUILT_IN_CLRSB):
+	  arg = gimple_call_arg (stmt, 0);
+	  prec = TYPE_PRECISION (TREE_TYPE (arg));
+	  mini = 0;
+	  maxi = prec - 1;
+	  goto bitop_builtin;
+	bitop_builtin:
+	  set_value_range (vr, VR_RANGE, build_int_cst (type, mini),
+			   build_int_cst (type, maxi), NULL);
+	  return;
+	default:
+	  break;
+	}
+    }
+  if (INTEGRAL_TYPE_P (type)
+      && gimple_stmt_nonnegative_warnv_p (stmt, &sop))
     set_value_range_to_nonnegative (vr, type,
 				    sop || stmt_overflow_infinity (stmt));
   else if (vrp_stmt_computes_nonzero (stmt, &sop)