NotAField printing improvements

Author: SingleAccretion

src/coreclr/jit/compiler.h

@@ -3625,6 +3625,7 @@ class Compiler
     void gtGetArgMsg(GenTreeCall* call, GenTree* arg, unsigned argNum, char* bufp, unsigned bufLength);
     void gtGetLateArgMsg(GenTreeCall* call, GenTree* arg, int argNum, char* bufp, unsigned bufLength);
     void gtDispArgList(GenTreeCall* call, GenTree* lastCallOperand, IndentStack* indentStack);
+    void gtDispAnyFieldSeq(FieldSeqNode* fieldSeq);
     void gtDispFieldSeq(FieldSeqNode* pfsn);
 
     void gtDispRange(LIR::ReadOnlyRange const& range);

src/coreclr/jit/gentree.cpp

@@ -9178,7 +9178,7 @@ void Compiler::gtDispZeroFieldSeq(GenTree* tree)
         if (map->Lookup(tree, &fldSeq))
         {
             printf(" Zero");
-            gtDispFieldSeq(fldSeq);
+            gtDispAnyFieldSeq(fldSeq);
         }
     }
 }
@@ -10295,9 +10295,28 @@ void Compiler::gtDispConst(GenTree* tree)
     }
 }
 
+//------------------------------------------------------------------------
+// gtDispFieldSeq: "gtDispFieldSeq" that also prints "<NotAField>".
+//
+// Useful for printing zero-offset field sequences.
+//
+void Compiler::gtDispAnyFieldSeq(FieldSeqNode* fieldSeq)
+{
+    if (fieldSeq == FieldSeqStore::NotAField())
+    {
+        printf(" Fseq<NotAField>");
+        return;
+    }
+
+    gtDispFieldSeq(fieldSeq);
+}
+
+//------------------------------------------------------------------------
+// gtDispFieldSeq: Print out the fields in this field sequence.
+//
 void Compiler::gtDispFieldSeq(FieldSeqNode* pfsn)
 {
-    if (pfsn == FieldSeqStore::NotAField() || (pfsn == nullptr))
+    if ((pfsn == nullptr) || (pfsn == FieldSeqStore::NotAField()))
     {
         return;
     }

src/coreclr/jit/morph.cpp

@@ -17844,7 +17844,7 @@ void Compiler::fgAddFieldSeqForZeroOffset(GenTree* addr, FieldSeqNode* fieldSeqZ
     if (verbose)
     {
         printf("\nfgAddFieldSeqForZeroOffset for");
-        gtDispFieldSeq(fieldSeqZero);
+        gtDispAnyFieldSeq(fieldSeqZero);
 
         printf("\naddr (Before)\n");
         gtDispNode(addr, nullptr, nullptr, false);

src/coreclr/jit/valuenum.cpp

@@ -4167,32 +4167,33 @@ ValueNum ValueNumStore::VNForFieldSeq(FieldSeqNode* fieldSeq)
     {
         return VNForNull();
     }
-    else if (fieldSeq == FieldSeqStore::NotAField())
+
+    ValueNum fieldSeqVN;
+    if (fieldSeq == FieldSeqStore::NotAField())
     {
         // We always allocate a new, unique VN in this call.
         Chunk*   c                 = GetAllocChunk(TYP_REF, CEA_NotAField);
         unsigned offsetWithinChunk = c->AllocVN();
-        ValueNum result            = c->m_baseVN + offsetWithinChunk;
-        return result;
+        fieldSeqVN                 = c->m_baseVN + offsetWithinChunk;
     }
     else
     {
         ssize_t  fieldHndVal = ssize_t(fieldSeq->m_fieldHnd);
         ValueNum fieldHndVN  = VNForHandle(fieldHndVal, GTF_ICON_FIELD_HDL);
         ValueNum seqNextVN   = VNForFieldSeq(fieldSeq->m_next);
-        ValueNum fieldSeqVN  = VNForFunc(TYP_REF, VNF_FieldSeq, fieldHndVN, seqNextVN);
+        fieldSeqVN           = VNForFunc(TYP_REF, VNF_FieldSeq, fieldHndVN, seqNextVN);
+    }
 
 #ifdef DEBUG
-        if (m_pComp->verbose)
-        {
-            printf("    FieldSeq");
-            vnDump(m_pComp, fieldSeqVN);
-            printf(" is " FMT_VN "\n", fieldSeqVN);
-        }
+    if (m_pComp->verbose)
+    {
+        printf("    FieldSeq");
+        vnDump(m_pComp, fieldSeqVN);
+        printf(" is " FMT_VN "\n", fieldSeqVN);
+    }
 #endif
 
-        return fieldSeqVN;
-    }
+    return fieldSeqVN;
 }
 
 FieldSeqNode* ValueNumStore::FieldSeqVNToFieldSeq(ValueNum vn)
@@ -5961,6 +5962,7 @@ void ValueNumStore::vnDump(Compiler* comp, ValueNum vn, bool isPtr)
         switch (funcApp.m_func)
         {
             case VNF_FieldSeq:
+            case VNF_NotAField:
                 vnDumpFieldSeq(comp, &funcApp, true);
                 break;
             case VNF_MapSelect:
@@ -6068,6 +6070,12 @@ void ValueNumStore::vnDumpExcSeq(Compiler* comp, VNFuncApp* excSeq, bool isHead)
 
 void ValueNumStore::vnDumpFieldSeq(Compiler* comp, VNFuncApp* fieldSeq, bool isHead)
 {
+    if (fieldSeq->m_func == VNF_NotAField)
+    {
+        printf("<NotAField>");
+        return;
+    }
+
     assert(fieldSeq->m_func == VNF_FieldSeq); // Precondition.
     // First arg is the field handle VN.
     assert(IsVNConstant(fieldSeq->m_args[0]) && TypeOfVN(fieldSeq->m_args[0]) == TYP_I_IMPL);