From 38b3590e40b7267195c65168e6ff064775de4339 Mon Sep 17 00:00:00 2001
From: Andreas Rumpf <rumpf_a@web.de>
Date: Sun, 20 Oct 2019 22:37:31 +0200
Subject: fixes #12310 [backport] (#12470)

---
 compiler/vmgen.nim | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

(limited to 'compiler/vmgen.nim')

diff --git a/compiler/vmgen.nim b/compiler/vmgen.nim
index 09e02f818..b528ff7be 100644
--- a/compiler/vmgen.nim
+++ b/compiler/vmgen.nim
@@ -948,9 +948,13 @@ proc genMagic(c: PCtx; n: PNode; dest: var TDest; m: TMagic) =
     c.genAddSubInt(n, dest, opcAddInt)
   of mInc, mDec:
     unused(c, n, dest)
-    let opc = if m == mInc: opcAddInt else: opcSubInt
+    let isUnsigned = n.sons[1].typ.skipTypes(abstractVarRange).kind in {tyUInt..tyUInt64}
+    let opc = if not isUnsigned:
+                if m == mInc: opcAddInt else: opcSubInt
+              else:
+                if m == mInc: opcAddu else: opcSubu
     let d = c.genx(n.sons[1])
-    if n.sons[2].isInt8Lit:
+    if n.sons[2].isInt8Lit and not isUnsigned:
       c.gABI(n, succ(opc), d, d, n.sons[2].intVal)
     else:
       let tmp = c.genx(n.sons[2])
-- 
cgit 1.4.1-2-gfad0