From 29ee636e56f22ed6e60f359d0dbd1f801f3eaca6 Mon Sep 17 00:00:00 2001
From: Martin Holst Swende <martin@swende.se>
Date: Thu, 8 Mar 2018 12:38:31 +0100
Subject: [PATCH] core/vm: make slt/sgt cleaner

---
 core/vm/instructions.go | 58 ++++++++++++-----------------------------
 1 file changed, 16 insertions(+), 42 deletions(-)

diff --git a/core/vm/instructions.go b/core/vm/instructions.go
index 15ed643ce1..66e804fb7e 100644
--- a/core/vm/instructions.go
+++ b/core/vm/instructions.go
@@ -198,32 +198,19 @@ func opSlt(pc *uint64, evm *EVM, contract *Contract, memory *Memory, stack *Stac
 	xSign := x.Cmp(tt255)
 	ySign := y.Cmp(tt255)
 
-	if xSign >= 0 {
-		//x negative
-		if ySign < 0 {
-			// y positive
-			y.SetUint64(1)
-			return nil, nil
-		}
-		// Both negative
+	switch {
+	case xSign >= 0 && ySign < 0:
+		y.SetUint64(1)
+
+	case xSign < 0 && ySign >= 0:
+		y.SetUint64(0)
+
+	default:
 		if x.Cmp(y) < 0 {
 			y.SetUint64(1)
 		} else {
 			y.SetUint64(0)
 		}
-	} else {
-		// x positive
-		if ySign >= 0 {
-			// y negative
-			y.SetUint64(0)
-			return nil, nil
-		}
-		// Both positive
-		if x.Cmp(y) >= 0 {
-			y.SetUint64(0)
-		} else {
-			y.SetUint64(1)
-		}
 	}
 	evm.interpreter.intPool.put(x)
 	return nil, nil
@@ -235,27 +222,14 @@ func opSgt(pc *uint64, evm *EVM, contract *Contract, memory *Memory, stack *Stac
 	xSign := x.Cmp(tt255)
 	ySign := y.Cmp(tt255)
 
-	if xSign >= 0 {
-		//x negative
-		if ySign < 0 {
-			// y positive
-			y.SetUint64(0)
-			return nil, nil
-		}
-		// Both negative (note: equality -> 0)
-		if x.Cmp(y) <= 0 {
-			y.SetUint64(0)
-		} else {
-			y.SetUint64(1)
-		}
-	} else {
-		// x positive
-		if ySign >= 0 {
-			// y negative
-			y.SetUint64(1)
-			return nil, nil
-		}
-		// Both positive
+	switch {
+	case xSign >= 0 && ySign < 0:
+		y.SetUint64(0)
+
+	case xSign < 0 && ySign >= 0:
+		y.SetUint64(1)
+
+	default:
 		if x.Cmp(y) > 0 {
 			y.SetUint64(1)
 		} else {