diff --git a/gcc/tree-ssa-phiopt.cc b/gcc/tree-ssa-phiopt.cc
index cffafe101a43b0f8b6afe585567d5c633cc4e439..be6128ed8dfecf4a2eaa9636c4fbfa3935738c4b 100644
--- a/gcc/tree-ssa-phiopt.cc
+++ b/gcc/tree-ssa-phiopt.cc
@@ -2690,7 +2690,7 @@ spaceship_replacement (basic_block cond_bb, basic_block middle_bb,
 	}
       else if (tree_to_shwi (arg1) != 2
 	       || absu_hwi (tree_to_shwi (arg0)) != 1
-	       || wi::to_widest (arg0) == wi::to_widest (arg1))
+	       || wi::to_widest (arg0) == wi::to_widest (arg2))
 	return false;
       switch (cmp2)
 	{