Keep precise argument sizes between import and morph.

Create `GT_PUTARG_TYPE` when signature type does not match node type.
Check in morph that this information has survived inlining and other phases between.

src/coreclr/src/jit/compiler.h

@@ -4356,11 +4356,10 @@ class Compiler
                            InlineCandidateInfo**  ppInlineCandidateInfo,
                            InlineResult*          inlineResult);
 
-    void impInlineRecordArgInfo(InlineInfo*      pInlineInfo,
-                                GenTree*         curArgVal,
-                                unsigned         argNum,
-                                unsigned __int64 bbFlags,
-                                InlineResult*    inlineResult);
+    void impInlineRecordArgInfo(InlineInfo*   pInlineInfo,
+                                GenTree*      curArgVal,
+                                unsigned      argNum,
+                                InlineResult* inlineResult);
 
     void impInlineInitVars(InlineInfo* pInlineInfo);
 
@@ -4665,6 +4664,8 @@ class Compiler
                                        BasicBlock* canonicalBlock,
                                        flowList*   predEdge);
 
+    GenTree* fgCheckCallArgUpdate(GenTree* parent, GenTree* child, var_types origType);
+
 #if defined(FEATURE_EH_FUNCLETS) && defined(TARGET_ARM)
     // Sometimes we need to defer updating the BBF_FINALLY_TARGET bit. fgNeedToAddFinallyTargetBits signals
     // when this is necessary.
@@ -10447,6 +10448,7 @@ class GenTreeVisitor
             case GT_NULLCHECK:
             case GT_PUTARG_REG:
             case GT_PUTARG_STK:
+            case GT_PUTARG_TYPE:
             case GT_RETURNTRAP:
             case GT_NOP:
             case GT_RETURN:

src/coreclr/src/jit/compiler.hpp

@@ -4387,6 +4387,7 @@ void GenTree::VisitOperands(TVisitor visitor)
         case GT_NULLCHECK:
         case GT_PUTARG_REG:
         case GT_PUTARG_STK:
+        case GT_PUTARG_TYPE:
 #if FEATURE_ARG_SPLIT
         case GT_PUTARG_SPLIT:
 #endif // FEATURE_ARG_SPLIT

src/coreclr/src/jit/ee_il_dll.cpp

@@ -360,7 +360,7 @@ unsigned Compiler::eeGetArgSize(CORINFO_ARG_LIST_HANDLE list, CORINFO_SIG_INFO*
     if (varTypeIsStruct(argType))
     {
         unsigned structSize = info.compCompHnd->getClassSize(argClass);
-        return structSize; // TODO: roundUp() needed here?
+        return roundUp(structSize, TARGET_POINTER_SIZE);
     }
 #endif // UNIX_AMD64_ABI
     return TARGET_POINTER_SIZE;

src/coreclr/src/jit/flowgraph.cpp

@@ -22743,7 +22743,11 @@ void Compiler::fgAttachStructInlineeToAsg(GenTree* tree, GenTree* child, CORINFO
 //    If the return type is a struct type and we're on a platform
 //    where structs can be returned in multiple registers, ensure the
 //    call has a suitable parent.
-
+//
+//    If the original call type and the substitution type are different
+//    the functions makes necessary updates. It could happen if there was
+//    an implicit conversion in the inlinee body.
+//
 Compiler::fgWalkResult Compiler::fgUpdateInlineReturnExpressionPlaceHolder(GenTree** pTree, fgWalkData* data)
 {
     // All the operations here and in the corresponding postorder
@@ -22798,6 +22802,29 @@ Compiler::fgWalkResult Compiler::fgUpdateInlineReturnExpressionPlaceHolder(GenTr
         }
 #endif // DEBUG
 
+        var_types newType = inlineCandidate->TypeGet();
+
+        // If we end up swapping type we may need to retype the tree:
+        if (retType != newType)
+        {
+            if ((retType == TYP_BYREF) && (tree->OperGet() == GT_IND))
+            {
+                // - in an RVA static if we've reinterpreted it as a byref;
+                assert(newType == TYP_I_IMPL);
+                JITDUMP("Updating type of the return GT_IND expression to TYP_BYREF\n");
+                inlineCandidate->gtType = TYP_BYREF;
+            }
+            else
+            {
+                // - under a call if we changed size of the argument.
+                GenTree* putArgType = comp->fgCheckCallArgUpdate(data->parent, inlineCandidate, retType);
+                if (putArgType != nullptr)
+                {
+                    inlineCandidate = putArgType;
+                }
+            }
+        }
+
         tree->ReplaceWith(inlineCandidate, comp);
         comp->compCurBB->bbFlags |= (bbFlags & BBF_SPLIT_GAINED);
 
@@ -22809,17 +22836,6 @@ Compiler::fgWalkResult Compiler::fgUpdateInlineReturnExpressionPlaceHolder(GenTr
             printf("\n");
         }
 #endif // DEBUG
-
-        var_types newType = tree->TypeGet();
-
-        // If we end up swapping in an RVA static we may need to retype it here,
-        // if we've reinterpreted it as a byref.
-        if ((retType != newType) && (retType == TYP_BYREF) && (tree->OperGet() == GT_IND))
-        {
-            assert(newType == TYP_I_IMPL);
-            JITDUMP("Updating type of the return GT_IND expression to TYP_BYREF\n");
-            tree->gtType = TYP_BYREF;
-        }
     }
 
     // If an inline was rejected and the call returns a struct, we may
@@ -23101,8 +23117,16 @@ Compiler::fgWalkResult Compiler::fgLateDevirtualization(GenTree** pTree, fgWalkD
     }
     else
     {
-        GenTree* foldedTree = comp->gtFoldExpr(tree);
-        *pTree              = foldedTree;
+        const var_types retType    = tree->TypeGet();
+        GenTree*        foldedTree = comp->gtFoldExpr(tree);
+        const var_types newType    = foldedTree->TypeGet();
+
+        GenTree* putArgType = comp->fgCheckCallArgUpdate(data->parent, foldedTree, retType);
+        if (putArgType != nullptr)
+        {
+            foldedTree = putArgType;
+        }
+        *pTree = foldedTree;
     }
 
     return WALK_CONTINUE;
@@ -23799,8 +23823,12 @@ Statement* Compiler::fgInlinePrependStatements(InlineInfo* inlineInfo)
         {
             const InlArgInfo& argInfo        = inlArgInfo[argNum];
             const bool        argIsSingleDef = !argInfo.argHasLdargaOp && !argInfo.argHasStargOp;
-            GenTree* const    argNode        = inlArgInfo[argNum].argNode;
-            unsigned __int64  bbFlags        = inlArgInfo[argNum].bbFlags;
+            GenTree*          argNode        = inlArgInfo[argNum].argNode;
+            const bool        argHasPutArg   = argNode->OperIs(GT_PUTARG_TYPE);
+
+            unsigned __int64 bbFlags = 0;
+            argNode                  = argNode->gtSkipPutArgType();
+            argNode                  = argNode->gtRetExprVal(&bbFlags);
 
             if (argInfo.argHasTmp)
             {
@@ -23820,7 +23848,11 @@ Statement* Compiler::fgInlinePrependStatements(InlineInfo* inlineInfo)
 
                 GenTree* argSingleUseNode = argInfo.argBashTmpNode;
 
-                if ((argSingleUseNode != nullptr) && !(argSingleUseNode->gtFlags & GTF_VAR_CLONED) && argIsSingleDef)
+                // argHasPutArg disqualifies the arg from a direct substitution because we don't have information about
+                // its user. For example: replace `LCL_VAR short` with `PUTARG_TYPE short->LCL_VAR int`,
+                // we should keep `PUTARG_TYPE` iff the user is a call that needs `short` and delete it otherwise.
+                if ((argSingleUseNode != nullptr) && !(argSingleUseNode->gtFlags & GTF_VAR_CLONED) && argIsSingleDef &&
+                    !argHasPutArg)
                 {
                     // Change the temp in-place to the actual argument.
                     // We currently do not support this for struct arguments, so it must not be a GT_OBJ.
@@ -26501,6 +26533,44 @@ void Compiler::fgTailMergeThrowsJumpToHelper(BasicBlock* predBlock,
     canonicalBlock->bbFlags |= (BBF_JMP_TARGET | BBF_HAS_LABEL);
 }
 
+//------------------------------------------------------------------------
+// fgCheckCallArgUpdate: check if we are replacing a call argument and add GT_PUTARG_TYPE if necessary.
+//
+// Arguments:
+//    parent   - the parent that could be a call;
+//    child    - the new child node;
+//    origType - the original child type;
+//
+// Returns:
+//   PUT_ARG_TYPE node if it is needed, nullptr otherwise.
+//
+GenTree* Compiler::fgCheckCallArgUpdate(GenTree* parent, GenTree* child, var_types origType)
+{
+    if ((parent == nullptr) || !parent->IsCall())
+    {
+        return nullptr;
+    }
+    const var_types newType = child->TypeGet();
+    if (newType == origType)
+    {
+        return nullptr;
+    }
+    if (varTypeIsStruct(origType) || (genTypeSize(origType) == genTypeSize(newType)))
+    {
+        assert(!varTypeIsStruct(newType));
+        return nullptr;
+    }
+    GenTree* putArgType = gtNewOperNode(GT_PUTARG_TYPE, origType, child);
+#if defined(DEBUG)
+    if (verbose)
+    {
+        printf("For call [%06d] the new argument's type [%06d]", dspTreeID(parent), dspTreeID(child));
+        printf(" does not match the original type size, add a GT_PUTARG_TYPE [%06d]\n", dspTreeID(parent));
+    }
+#endif
+    return putArgType;
+}
+
 #ifdef DEBUG
 
 //------------------------------------------------------------------------

src/coreclr/src/jit/gentree.cpp

@@ -5112,6 +5112,7 @@ bool GenTree::TryGetUse(GenTree* def, GenTree*** use)
         case GT_NULLCHECK:
         case GT_PUTARG_REG:
         case GT_PUTARG_STK:
+        case GT_PUTARG_TYPE:
         case GT_RETURNTRAP:
         case GT_NOP:
         case GT_RETURN:
@@ -9107,6 +9108,7 @@ GenTreeUseEdgeIterator::GenTreeUseEdgeIterator(GenTree* node)
         case GT_NULLCHECK:
         case GT_PUTARG_REG:
         case GT_PUTARG_STK:
+        case GT_PUTARG_TYPE:
         case GT_BSWAP:
         case GT_BSWAP16:
         case GT_KEEPALIVE:
@@ -12021,7 +12023,7 @@ void Compiler::gtGetArgMsg(GenTreeCall* call, GenTree* arg, unsigned argNum, cha
             }
 #endif // TARGET_ARM
 #if FEATURE_FIXED_OUT_ARGS
-            sprintf_s(bufp, bufLength, "arg%d out+%02x%c", argNum, curArgTabEntry->slotNum * TARGET_POINTER_SIZE, 0);
+            sprintf_s(bufp, bufLength, "arg%d out+%02x%c", argNum, curArgTabEntry->GetByteOffset(), 0);
 #else
             sprintf_s(bufp, bufLength, "arg%d on STK%c", argNum, 0);
 #endif
@@ -15517,7 +15519,7 @@ GenTree* Compiler::gtNewTempAssign(
         // There are 2 special cases:
         // 1. we have lost classHandle from a FIELD node  because the parent struct has overlapping fields,
         //     the field was transformed as IND opr GT_LCL_FLD;
-        // 2. we are propogating `ASG(struct V01, 0)` to `RETURN(struct V01)`, `CNT_INT` doesn't `structHnd`;
+        // 2. we are propagation `ASG(struct V01, 0)` to `RETURN(struct V01)`, `CNT_INT` doesn't `structHnd`;
         // in these cases, we can use the type of the merge return for the assignment.
         assert(val->OperIs(GT_IND, GT_LCL_FLD, GT_CNS_INT));
         assert(!compDoOldStructRetyping());

src/coreclr/src/jit/gentree.h

@@ -1736,7 +1736,9 @@ struct GenTree
     inline GenTree* gtEffectiveVal(bool commaOnly = false);
 
     // Tunnel through any GT_RET_EXPRs
-    inline GenTree* gtRetExprVal(unsigned __int64* pbbFlags);
+    inline GenTree* gtRetExprVal(unsigned __int64* pbbFlags = nullptr);
+
+    inline GenTree* gtSkipPutArgType();
 
     // Return the child of this node if it is a GT_RELOAD or GT_COPY; otherwise simply return the node itself
     inline GenTree* gtSkipReloadOrCopy();
@@ -7111,14 +7113,15 @@ inline GenTree* GenTree::gtGetOp2IfPresent() const
     return op2;
 }
 
-inline GenTree* GenTree::gtEffectiveVal(bool commaOnly)
+inline GenTree* GenTree::gtEffectiveVal(bool commaOnly /* = false */)
 {
     GenTree* effectiveVal = this;
     for (;;)
     {
+        assert(!effectiveVal->OperIs(GT_PUTARG_TYPE));
         if (effectiveVal->gtOper == GT_COMMA)
         {
-            effectiveVal = effectiveVal->AsOp()->gtOp2;
+            effectiveVal = effectiveVal->AsOp()->gtGetOp2();
         }
         else if (!commaOnly && (effectiveVal->gtOper == GT_NOP) && (effectiveVal->AsOp()->gtOp1 != nullptr))
         {
@@ -7147,23 +7150,49 @@ inline GenTree* GenTree::gtEffectiveVal(bool commaOnly)
 //    Multi-level inlines can form chains of GT_RET_EXPRs.
 //    This method walks back to the root of the chain.
 
-inline GenTree* GenTree::gtRetExprVal(unsigned __int64* pbbFlags)
+inline GenTree* GenTree::gtRetExprVal(unsigned __int64* pbbFlags /* = nullptr */)
 {
     GenTree*         retExprVal = this;
     unsigned __int64 bbFlags    = 0;
 
-    assert(pbbFlags != nullptr);
+    assert(!retExprVal->OperIs(GT_PUTARG_TYPE));
 
-    for (; retExprVal->gtOper == GT_RET_EXPR; retExprVal = retExprVal->AsRetExpr()->gtInlineCandidate)
+    while (retExprVal->OperIs(GT_RET_EXPR))
     {
-        bbFlags = retExprVal->AsRetExpr()->bbFlags;
+        const GenTreeRetExpr* retExpr = retExprVal->AsRetExpr();
+        bbFlags                       = retExpr->bbFlags;
+        retExprVal                    = retExpr->gtInlineCandidate;
     }
 
-    *pbbFlags = bbFlags;
+    if (pbbFlags != nullptr)
+    {
+        *pbbFlags = bbFlags;
+    }
 
     return retExprVal;
 }
 
+//-------------------------------------------------------------------------
+// gtSkipPutArgType - skip PUTARG_TYPE if it is presented.
+//
+// Returns:
+//    the original tree or its child if it was a PUTARG_TYPE.
+//
+// Notes:
+//   PUTARG_TYPE should be skipped when we are doing transformations
+//   that are not affected by ABI, for example: inlining, implicit byref morphing.
+//
+inline GenTree* GenTree::gtSkipPutArgType()
+{
+    if (OperIs(GT_PUTARG_TYPE))
+    {
+        GenTree* res = AsUnOp()->gtGetOp1();
+        assert(!res->OperIs(GT_PUTARG_TYPE));
+        return res;
+    }
+    return this;
+}
+
 inline GenTree* GenTree::gtSkipReloadOrCopy()
 {
     // There can be only one reload or copy (we can't have a reload/copy of a reload/copy)

src/coreclr/src/jit/gtlist.h

@@ -292,6 +292,7 @@ GTNODE(PUTARG_REG       , GenTreeMultiRegOp  ,0,GTK_UNOP)
 #else
 GTNODE(PUTARG_REG       , GenTreeOp          ,0,GTK_UNOP)                        // operator that places outgoing arg in register
 #endif
+GTNODE(PUTARG_TYPE      , GenTreeOp          ,0,GTK_UNOP|GTK_NOTLIR)             // operator that places saves argument type between importation and morph
 GTNODE(PUTARG_STK       , GenTreePutArgStk   ,0,GTK_UNOP|GTK_NOVALUE)            // operator that places outgoing arg in stack
 #if FEATURE_ARG_SPLIT
 GTNODE(PUTARG_SPLIT     , GenTreePutArgSplit ,0,GTK_UNOP)                        // operator that places outgoing arg in registers with stack (split struct in ARM32)