diff --git a/core/vm/analysis.go b/core/vm/analysis.go
index 9a678627aee8d..bf05963385330 100644
--- a/core/vm/analysis.go
+++ b/core/vm/analysis.go
@@ -85,7 +85,7 @@ func codeBitmapInternal(code, bits bitvec) bitvec {
 		if int8(op) < int8(PUSH1) { // If not PUSH (the int8(op) > int(PUSH32) is always false).
 			continue
 		}
-		numbits := op - PUSH1 + 1
+		numbits := uint64(op - PUSH1 + 1)
 		if numbits >= 8 {
 			if numbits >= 16 {
 				bits.set16(pc)
@@ -119,7 +119,7 @@ func codeBitmapInternal(code, bits bitvec) bitvec {
 		case 7:
 			bits.setN(set7BitsMask, pc)
 		}
-		pc += uint64(numbits)
+		pc += numbits
 	}
 	return bits
 }