fixes #19198 [backport:1.6] (#19209)

* fixes #19198 [backport:1.6]

* added a test case

2 files changed, 20 insertions, 14 deletions

diff --git a/compiler/vm.nim b/compiler/vm.nim
index d58a49f9e..3343eb781 100644
--- a/compiler/vm.nim
+++ b/compiler/vm.nim
@@ -434,8 +434,10 @@ proc opConv(c: PCtx; dest: var TFullReg, src: TFullReg, desttyp, srctyp: PType):
       of tyFloat..tyFloat64:
         dest.intVal = int(src.floatVal)
       else:
-        let srcDist = (sizeof(src.intVal) - styp.size) * 8
-        let destDist = (sizeof(dest.intVal) - desttyp.size) * 8
+        let srcSize = getSize(c.config, styp)
+        let destSize = getSize(c.config, desttyp)
+        let srcDist = (sizeof(src.intVal) - srcSize) * 8
+        let destDist = (sizeof(dest.intVal) - destSize) * 8
         var value = cast[BiggestUInt](src.intVal)
         value = (value shl srcDist) shr srcDist
         value = (value shl destDist) shr destDist
diff --git a/compiler/vmgen.nim b/compiler/vmgen.nim
index 9a823dff4..c0c4bac19 100644
--- a/compiler/vmgen.nim
+++ b/compiler/vmgen.nim
@@ -749,18 +749,20 @@ proc genNarrow(c: PCtx; n: PNode; dest: TDest) =
   let t = skipTypes(n.typ, abstractVar-{tyTypeDesc})
   # uint is uint64 in the VM, we we only need to mask the result for
   # other unsigned types:
-  if t.kind in {tyUInt8..tyUInt32} or (t.kind == tyUInt and t.size < 8):
-    c.gABC(n, opcNarrowU, dest, TRegister(t.size*8))
-  elif t.kind in {tyInt8..tyInt32} or (t.kind == tyInt and t.size < 8):
-    c.gABC(n, opcNarrowS, dest, TRegister(t.size*8))
+  let size = getSize(c.config, t)
+  if t.kind in {tyUInt8..tyUInt32} or (t.kind == tyUInt and size < 8):
+    c.gABC(n, opcNarrowU, dest, TRegister(size*8))
+  elif t.kind in {tyInt8..tyInt32} or (t.kind == tyInt and size < 8):
+    c.gABC(n, opcNarrowS, dest, TRegister(size*8))
 
 proc genNarrowU(c: PCtx; n: PNode; dest: TDest) =
   let t = skipTypes(n.typ, abstractVar-{tyTypeDesc})
   # uint is uint64 in the VM, we we only need to mask the result for
   # other unsigned types:
+  let size = getSize(c.config, t)
   if t.kind in {tyUInt8..tyUInt32, tyInt8..tyInt32} or
-    (t.kind in {tyUInt, tyInt} and t.size < 8):
-    c.gABC(n, opcNarrowU, dest, TRegister(t.size*8))
+    (t.kind in {tyUInt, tyInt} and size < 8):
+    c.gABC(n, opcNarrowU, dest, TRegister(size*8))
 
 proc genBinaryABCnarrow(c: PCtx; n: PNode; dest: var TDest; opc: TOpcode) =
   genBinaryABC(c, n, dest, opc)
@@ -1088,10 +1090,11 @@ proc genMagic(c: PCtx; n: PNode; dest: var TDest; m: TMagic) =
     genBinaryABC(c, n, dest, opcShlInt)
     # genNarrowU modified
     let t = skipTypes(n.typ, abstractVar-{tyTypeDesc})
-    if t.kind in {tyUInt8..tyUInt32} or (t.kind == tyUInt and t.size < 8):
-      c.gABC(n, opcNarrowU, dest, TRegister(t.size*8))
-    elif t.kind in {tyInt8..tyInt32} or (t.kind == tyInt and t.size < 8):
-      c.gABC(n, opcSignExtend, dest, TRegister(t.size*8))
+    let size = getSize(c.config, t)
+    if t.kind in {tyUInt8..tyUInt32} or (t.kind == tyUInt and size < 8):
+      c.gABC(n, opcNarrowU, dest, TRegister(size*8))
+    elif t.kind in {tyInt8..tyInt32} or (t.kind == tyInt and size < 8):
+      c.gABC(n, opcSignExtend, dest, TRegister(size*8))
   of mAshrI: genBinaryABC(c, n, dest, opcAshrInt)
   of mBitandI: genBinaryABC(c, n, dest, opcBitandInt)
   of mBitorI: genBinaryABC(c, n, dest, opcBitorInt)
@@ -1125,8 +1128,9 @@ proc genMagic(c: PCtx; n: PNode; dest: var TDest; m: TMagic) =
     genUnaryABC(c, n, dest, opcBitnotInt)
     #genNarrowU modified, do not narrow signed types
     let t = skipTypes(n.typ, abstractVar-{tyTypeDesc})
-    if t.kind in {tyUInt8..tyUInt32} or (t.kind == tyUInt and t.size < 8):
-      c.gABC(n, opcNarrowU, dest, TRegister(t.size*8))
+    let size = getSize(c.config, t)
+    if t.kind in {tyUInt8..tyUInt32} or (t.kind == tyUInt and size < 8):
+      c.gABC(n, opcNarrowU, dest, TRegister(size*8))
   of mCharToStr, mBoolToStr, mIntToStr, mInt64ToStr, mFloatToStr, mCStrToStr, mStrToStr, mEnumToStr:
     genConv(c, n, n[1], dest)
   of mEqStr, mEqCString: genBinaryABC(c, n, dest, opcEqStr)