Remove recursion in simplify_control_stmt_condition_1 [PR114855].

Remove some ad-hoc simplification code in the forward threader, as the
call into the ranger in m_simplifier->simplify() will handle anything we
can do manually in simplify_control_stmt_condition_1.

In PR114855, DOM time is reduced from 120s to 92s (-23%) and overall
compilation time from 235s to 205s (-12%).  The total thread count at -O1 is
unchanged for the testcase.

In our bootstrap .ii benchmark suite, I see we thread 3 threads less
over all files at -O1.  At -O2, the backward threader picks up one more,
for no difference over all.

	PR tree-optimization/114855

gcc/ChangeLog:

	* tree-ssa-threadedge.cc: Remove unneeded recursion.

1 files changed, 0 insertions, 118 deletions

diff --git a/gcc/tree-ssa-threadedge.cc b/gcc/tree-ssa-threadedge.cc
index 0aa2aa8..207ec34 100644
--- a/gcc/tree-ssa-threadedge.cc
+++ b/gcc/tree-ssa-threadedge.cc
@@ -496,124 +496,6 @@ jump_threader::simplify_control_stmt_condition_1
       std::swap (op0, op1);
     }
 
-  /* If the condition has the form (A & B) CMP 0 or (A | B) CMP 0 then
-     recurse into the LHS to see if there is a simplification that
-     makes this condition always true or always false along the edge
-     E.  */
-  if ((cond_code == EQ_EXPR || cond_code == NE_EXPR)
-      && TREE_CODE (op0) == SSA_NAME
-      && integer_zerop (op1))
-    {
-      gimple *def_stmt = SSA_NAME_DEF_STMT (op0);
-      if (gimple_code (def_stmt) != GIMPLE_ASSIGN)
-        ;
-      else if (gimple_assign_rhs_code (def_stmt) == BIT_AND_EXPR
-	       || gimple_assign_rhs_code (def_stmt) == BIT_IOR_EXPR)
-	{
-	  enum tree_code rhs_code = gimple_assign_rhs_code (def_stmt);
-	  const tree rhs1 = gimple_assign_rhs1 (def_stmt);
-	  const tree rhs2 = gimple_assign_rhs2 (def_stmt);
-
-	  /* Is A != 0 ?  */
-	  const tree res1
-	    = simplify_control_stmt_condition_1 (e, def_stmt,
-						 rhs1, NE_EXPR, op1,
-						 limit - 1);
-	  if (res1 == NULL_TREE)
-	    ;
-	  else if (rhs_code == BIT_AND_EXPR && integer_zerop (res1))
-	    {
-	      /* If A == 0 then (A & B) != 0 is always false.  */
-	      if (cond_code == NE_EXPR)
-	        return boolean_false_node;
-	      /* If A == 0 then (A & B) == 0 is always true.  */
-	      if (cond_code == EQ_EXPR)
-		return boolean_true_node;
-	    }
-	  else if (rhs_code == BIT_IOR_EXPR && integer_nonzerop (res1))
-	    {
-	      /* If A != 0 then (A | B) != 0 is always true.  */
-	      if (cond_code == NE_EXPR)
-		return boolean_true_node;
-	      /* If A != 0 then (A | B) == 0 is always false.  */
-	      if (cond_code == EQ_EXPR)
-		return boolean_false_node;
-	    }
-
-	  /* Is B != 0 ?  */
-	  const tree res2
-	    = simplify_control_stmt_condition_1 (e, def_stmt,
-						 rhs2, NE_EXPR, op1,
-						 limit - 1);
-	  if (res2 == NULL_TREE)
-	    ;
-	  else if (rhs_code == BIT_AND_EXPR && integer_zerop (res2))
-	    {
-	      /* If B == 0 then (A & B) != 0 is always false.  */
-	      if (cond_code == NE_EXPR)
-	        return boolean_false_node;
-	      /* If B == 0 then (A & B) == 0 is always true.  */
-	      if (cond_code == EQ_EXPR)
-		return boolean_true_node;
-	    }
-	  else if (rhs_code == BIT_IOR_EXPR && integer_nonzerop (res2))
-	    {
-	      /* If B != 0 then (A | B) != 0 is always true.  */
-	      if (cond_code == NE_EXPR)
-		return boolean_true_node;
-	      /* If B != 0 then (A | B) == 0 is always false.  */
-	      if (cond_code == EQ_EXPR)
-		return boolean_false_node;
-	    }
-
-	  if (res1 != NULL_TREE && res2 != NULL_TREE)
-	    {
-	      if (rhs_code == BIT_AND_EXPR
-		  && TYPE_PRECISION (TREE_TYPE (op0)) == 1
-		  && integer_nonzerop (res1)
-		  && integer_nonzerop (res2))
-		{
-		  /* If A != 0 and B != 0 then (bool)(A & B) != 0 is true.  */
-		  if (cond_code == NE_EXPR)
-		    return boolean_true_node;
-		  /* If A != 0 and B != 0 then (bool)(A & B) == 0 is false.  */
-		  if (cond_code == EQ_EXPR)
-		    return boolean_false_node;
-		}
-
-	      if (rhs_code == BIT_IOR_EXPR
-		  && integer_zerop (res1)
-		  && integer_zerop (res2))
-		{
-		  /* If A == 0 and B == 0 then (A | B) != 0 is false.  */
-		  if (cond_code == NE_EXPR)
-		    return boolean_false_node;
-		  /* If A == 0 and B == 0 then (A | B) == 0 is true.  */
-		  if (cond_code == EQ_EXPR)
-		    return boolean_true_node;
-		}
-	    }
-	}
-      /* Handle (A CMP B) CMP 0.  */
-      else if (TREE_CODE_CLASS (gimple_assign_rhs_code (def_stmt))
-	       == tcc_comparison)
-	{
-	  tree rhs1 = gimple_assign_rhs1 (def_stmt);
-	  tree rhs2 = gimple_assign_rhs2 (def_stmt);
-
-	  tree_code new_cond = gimple_assign_rhs_code (def_stmt);
-	  if (cond_code == EQ_EXPR)
-	    new_cond = invert_tree_comparison (new_cond, false);
-
-	  tree res
-	    = simplify_control_stmt_condition_1 (e, def_stmt,
-						 rhs1, new_cond, rhs2,
-						 limit - 1);
-	  if (res != NULL_TREE && is_gimple_min_invariant (res))
-	    return res;
-	}
-    }
-
   gimple_cond_set_code (dummy_cond, cond_code);
   gimple_cond_set_lhs (dummy_cond, op0);
   gimple_cond_set_rhs (dummy_cond, op1);