diff --git a/gcc/match.pd b/gcc/match.pd
index 97db0eb5f25..39c9c81966a 100644
--- a/gcc/match.pd
+++ b/gcc/match.pd
@@ -2181,6 +2181,16 @@ DEFINE_INT_AND_FLOAT_ROUND_FN (RINT)
       && (TYPE_UNSIGNED (type)
 	  || TYPE_PRECISION (type) > 1))))
 
+/* (a&1) is always [0,1] too. This is useful again when
+   the range is not known. */
+(match zero_one_valued_p
+ (bit_and:c@0 @1 zero_one_valued_p))
+
+/* A conversion from an zero_one_valued_p is still a [0,1].
+   This is useful when the range of a variable is not known */
+(match zero_one_valued_p
+ (convert@0 zero_one_valued_p))
+
 /* Transform { 0 or 1 } * { 0 or 1 } into { 0 or 1 } & { 0 or 1 }.  */
 (simplify
  (mult zero_one_valued_p@0 zero_one_valued_p@1)
diff --git a/gcc/testsuite/gcc.dg/tree-ssa/bool-13.c b/gcc/testsuite/gcc.dg/tree-ssa/bool-13.c
index 438f15a484a..de8c99a7727 100644
--- a/gcc/testsuite/gcc.dg/tree-ssa/bool-13.c
+++ b/gcc/testsuite/gcc.dg/tree-ssa/bool-13.c
@@ -1,5 +1,5 @@
 /* { dg-do compile } */
-/* { dg-options "-O1 -fdump-tree-optimized -fdump-tree-original -fdump-tree-phiopt1 -fdump-tree-forwprop2" } */
+/* { dg-options "-O1 -fdump-tree-optimized -fdump-tree-original -fdump-tree-forwprop1 -fdump-tree-forwprop2" } */
 #define bool _Bool
 int maxbool(bool ab, bool bb)
 {
@@ -22,15 +22,10 @@ int minbool(bool ab, bool bb)
 /* { dg-final { scan-tree-dump-times "MIN_EXPR" 1 "original" } } */
 /* { dg-final { scan-tree-dump-times "if " 0 "original" } } */
 
-/* PHI-OPT1 should have kept it as min/max. */
-/* { dg-final { scan-tree-dump-times "MAX_EXPR" 1 "phiopt1" } } */
-/* { dg-final { scan-tree-dump-times "MIN_EXPR" 1 "phiopt1" } } */
-/* { dg-final { scan-tree-dump-times "if " 0 "phiopt1" } } */
-
-/* Forwprop2 (after ccp) will convert it into &\| */
-/* { dg-final { scan-tree-dump-times "MAX_EXPR" 0 "forwprop2" } } */
-/* { dg-final { scan-tree-dump-times "MIN_EXPR" 0 "forwprop2" } } */
-/* { dg-final { scan-tree-dump-times "if " 0 "forwprop2" } } */
+/* Forwprop1 will convert it into &\| as we can detect that the arguments are one_zero. */
+/* { dg-final { scan-tree-dump-times "MAX_EXPR" 0 "forwprop1" } } */
+/* { dg-final { scan-tree-dump-times "MIN_EXPR" 0 "forwprop1" } } */
+/* { dg-final { scan-tree-dump-times "if " 0 "forwprop1" } } */
 
 /* By optimize there should be no min/max nor if  */
 /* { dg-final { scan-tree-dump-times "MAX_EXPR" 0 "optimized" } } */