prog: reduce len mutation priority

Mutating LenType only produces "incorrect" results according to descriptions,
we generally try to do it less often (there is infinite space of incorrect inputs).

2 files changed, 3 insertions, 2 deletions

diff --git a/prog/mutation.go b/prog/mutation.go
index 7868c6445..f70a62cbe 100644
--- a/prog/mutation.go
+++ b/prog/mutation.go
@@ -629,7 +629,8 @@ func (t *VmaType) getMutationPrio(target *Target, arg Arg, ignoreSpecial bool) (
 }
 
 func (t *LenType) getMutationPrio(target *Target, arg Arg, ignoreSpecial bool) (prio float64, stopRecursion bool) {
-	return 0.6 * maxPriority, false
+	// Mutating LenType only produces "incorrect" results according to descriptions.
+	return 0.1 * maxPriority, false
 }
 
 func (t *BufferType) getMutationPrio(target *Target, arg Arg, ignoreSpecial bool) (prio float64, stopRecursion bool) {
diff --git a/prog/size.go b/prog/size.go
index 8f7f15d4e..b621cb6bc 100644
--- a/prog/size.go
+++ b/prog/size.go
@@ -175,7 +175,7 @@ func (r *randGen) mutateSize(arg *ConstArg, parent []Arg) bool {
 		if arg.Val != 0 && r.bin() {
 			arg.Val = r.randRangeInt(0, arg.Val-1, arg.Type().TypeBitSize(), 0)
 		} else {
-			arg.Val = r.randRangeInt(arg.Val+1, arg.Val+1000, arg.Type().TypeBitSize(), 0)
+			arg.Val = r.randRangeInt(arg.Val+1, arg.Val+100, arg.Type().TypeBitSize(), 0)
 		}
 		return true
 	}