Fix for casting byref to double in morph

This fixes https://github.com/dotnet/coreclr/issues/3517.
JIT didn't cast byref to double in morph, which caused
this assertion later.
The fix is to handle such case as well.

1 files changed, 12 insertions, 24 deletions

diff --git a/src/jit/morph.cpp b/src/jit/morph.cpp
index 16ece5f76f..3858a20d25 100644
--- a/src/jit/morph.cpp
+++ b/src/jit/morph.cpp
@@ -502,34 +502,22 @@ GenTreePtr          Compiler::fgMorphCast(GenTreePtr tree)
         // it believes the variable is a GC variable at the begining of the
         // instruction group, but is not turned non-gc by the code generator
         // we fix this by copying the GC pointer to a non-gc pointer temp.
-        if (varTypeIsFloating(srcType) == varTypeIsFloating(dstType))
-        {
-            noway_assert(!varTypeIsGC(dstType) && "How can we have a cast to a GCRef here?");
-
-            // We generate an assignment to an int and then do the cast from an int. With this we avoid
-            // the gc problem and we allow casts to bytes, longs,  etc...
-            var_types typInter;
-            typInter = TYP_I_IMPL;
+        noway_assert(!varTypeIsGC(dstType) && "How can we have a cast to a GCRef here?");
 
-            unsigned lclNum = lvaGrabTemp(true DEBUGARG("Cast away GC"));
-            oper->gtType = typInter;
-            GenTreePtr asg  = gtNewTempAssign(lclNum, oper);
-            oper->gtType = srcType;
+        // We generate an assignment to an int and then do the cast from an int. With this we avoid
+        // the gc problem and we allow casts to bytes, longs,  etc...
+        unsigned lclNum = lvaGrabTemp(true DEBUGARG("Cast away GC"));
+        oper->gtType = TYP_I_IMPL;
+        GenTreePtr asg = gtNewTempAssign(lclNum, oper);
+        oper->gtType = srcType;
 
-            // do the real cast
-            GenTreePtr cast = gtNewCastNode(tree->TypeGet(), gtNewLclvNode(lclNum, typInter), dstType);
+        // do the real cast
+        GenTreePtr cast = gtNewCastNode(tree->TypeGet(), gtNewLclvNode(lclNum, TYP_I_IMPL), dstType);
 
-            // Generate the comma tree
-            oper   = gtNewOperNode(GT_COMMA, tree->TypeGet(), asg, cast);
+        // Generate the comma tree
+        oper = gtNewOperNode(GT_COMMA, tree->TypeGet(), asg, cast);
 
-            return fgMorphTree(oper);
-        }
-        else
-        {
-            tree->gtCast.CastOp() = fgMorphTree(oper);
-            tree->gtFlags |= (tree->gtCast.CastOp()->gtFlags & GTF_ALL_EFFECT);
-            return tree;
-        }
+        return fgMorphTree(oper);
     }
 
     // Look for narrowing casts ([u]long -> [u]int) and try to push them