diff --git a/Zend/Optimizer/zend_ssa.c b/Zend/Optimizer/zend_ssa.c
index 186af867458..590df8155e3 100644
--- a/Zend/Optimizer/zend_ssa.c
+++ b/Zend/Optimizer/zend_ssa.c
@@ -142,7 +142,7 @@ static void pi_range(
 	constraint->range.underflow = underflow;
 	constraint->range.overflow = overflow;
 	constraint->negative = negative ? NEG_INIT : NEG_NONE;
-	phi->has_range_constraint = 1;
+	phi->has_range_constraint = true;
 }
 /* }}} */
 
@@ -160,7 +160,7 @@ static inline void pi_range_max(zend_ssa_phi *phi, int var, zend_long val) {
 }
 
 static void pi_type_mask(zend_ssa_phi *phi, uint32_t type_mask) {
-	phi->has_range_constraint = 0;
+	phi->has_range_constraint = false;
 	phi->constraint.type.ce = NULL;
 	phi->constraint.type.type_mask = MAY_BE_REF|MAY_BE_RC1|MAY_BE_RCN;
 	phi->constraint.type.type_mask |= type_mask;
diff --git a/Zend/Optimizer/zend_ssa.h b/Zend/Optimizer/zend_ssa.h
index 5a6fce38d2f..b59c59a1b86 100644
--- a/Zend/Optimizer/zend_ssa.h
+++ b/Zend/Optimizer/zend_ssa.h
@@ -67,8 +67,7 @@ struct _zend_ssa_phi {
 	int                    var;           /* Original CV, VAR or TMP variable index */
 	int                    ssa_var;       /* SSA variable index */
 	int                    block;         /* current BB index */
-	int                    visited : 1;   /* flag to avoid recursive processing */
-	int                    has_range_constraint : 1;
+	bool                   has_range_constraint : 1;
 	zend_ssa_phi         **use_chains;
 	zend_ssa_phi          *sym_use_chain;
 	int                   *sources;       /* Array of SSA IDs that produce this var.