diff --git a/gcc/tree-ssa-phiopt.c b/gcc/tree-ssa-phiopt.c
index 0e339c46afa29fa97f90d9bc4394370cd9b4b396..65b25be3399b75d5e9cab0f78aa2340418571a33 100644
--- a/gcc/tree-ssa-phiopt.c
+++ b/gcc/tree-ssa-phiopt.c
@@ -2037,6 +2037,7 @@ spaceship_replacement (basic_block cond_bb, basic_block middle_bb,
   tree lhs, rhs;
   gimple *orig_use_stmt = use_stmt;
   tree orig_use_lhs = NULL_TREE;
+  bool is_canon = false;
   int prec = TYPE_PRECISION (TREE_TYPE (phires));
   if (is_gimple_assign (use_stmt)
       && gimple_assign_rhs_code (use_stmt) == BIT_AND_EXPR
@@ -2063,6 +2064,26 @@ spaceship_replacement (basic_block cond_bb, basic_block middle_bb,
     }
   else if (is_gimple_assign (use_stmt))
     {
+      /* Deal with if match.pd has rewritten the (res & ~1) == 0
+	 into res <= 1 and has left a type-cast for signed types.  */
+      if (gimple_assign_cast_p (use_stmt))
+	{
+	  orig_use_lhs = gimple_assign_lhs (use_stmt);
+	  if (SSA_NAME_OCCURS_IN_ABNORMAL_PHI (orig_use_lhs))
+	    return false;
+	  if (EDGE_COUNT (phi_bb->preds) != 4)
+	    return false;
+	  if (!TYPE_UNSIGNED (TREE_TYPE (orig_use_lhs)))
+	    return false;
+	  if (!single_imm_use (orig_use_lhs, &use_p, &use_stmt))
+	    return false;
+	  tree_code cmp;
+	  if (is_gimple_assign (use_stmt)
+	      && (cmp = gimple_assign_rhs_code (use_stmt))
+	      && (cmp == LE_EXPR || cmp == GT_EXPR)
+	      && wi::eq_p (wi::to_wide (gimple_assign_rhs2 (use_stmt)), 1))
+	    is_canon = true;
+	}
       if (gimple_assign_rhs_class (use_stmt) == GIMPLE_BINARY_RHS)
 	{
 	  cmp = gimple_assign_rhs_code (use_stmt);
@@ -2099,7 +2120,9 @@ spaceship_replacement (basic_block cond_bb, basic_block middle_bb,
       || !tree_fits_shwi_p (rhs)
       || !IN_RANGE (tree_to_shwi (rhs), -1, 1))
     return false;
-  if (orig_use_lhs)
+  /* If we're already in the canonical form we need to keep the original
+     comparison.  */
+  if (orig_use_lhs && !is_canon)
     {
       if ((cmp != EQ_EXPR && cmp != NE_EXPR) || !integer_zerop (rhs))
 	return false;
@@ -2310,6 +2333,7 @@ spaceship_replacement (basic_block cond_bb, basic_block middle_bb,
     one_cmp = GT_EXPR;
 
   enum tree_code res_cmp;
+
   switch (cmp)
     {
     case EQ_EXPR:
@@ -2345,6 +2369,8 @@ spaceship_replacement (basic_block cond_bb, basic_block middle_bb,
 	res_cmp = one_cmp == LT_EXPR ? GE_EXPR : LE_EXPR;
       else if (integer_minus_onep (rhs))
 	res_cmp = one_cmp == LT_EXPR ? GT_EXPR : LT_EXPR;
+      else if (integer_onep (rhs) && is_canon)
+	res_cmp = GE_EXPR;
       else
 	return false;
       break;
@@ -2353,6 +2379,8 @@ spaceship_replacement (basic_block cond_bb, basic_block middle_bb,
 	res_cmp = one_cmp == LT_EXPR ? LE_EXPR : GE_EXPR;
       else if (integer_zerop (rhs))
 	res_cmp = one_cmp;
+      else if (integer_onep (rhs) && is_canon)
+	res_cmp = LE_EXPR;
       else
 	return false;
       break;