Don't use GT_ARR_ELEM as a location/value (#54780)

* Don't use GT_ARR_ELEM as a location

It represents an address.

No diffs.

* Clarify the purpose of GenTreeArrElem

4 files changed, 4 insertions, 13 deletions

diff --git a/src/coreclr/jit/assertionprop.cpp b/src/coreclr/jit/assertionprop.cpp
index fb869c89fee..ffad32a61b2 100644
--- a/src/coreclr/jit/assertionprop.cpp
+++ b/src/coreclr/jit/assertionprop.cpp
@@ -1248,13 +1248,6 @@ AssertionIndex Compiler::optCreateAssertion(GenTree*         op1,
                     toType = op2->gtType;
                     goto SUBRANGE_COMMON;
 
-                case GT_ARR_ELEM:
-
-                    /* Assigning the result of an indirection into a LCL_VAR, see if we can add a subrange assertion */
-
-                    toType = op2->gtType;
-                    goto SUBRANGE_COMMON;
-
                 case GT_LCL_FLD:
 
                     /* Assigning the result of an indirection into a LCL_VAR, see if we can add a subrange assertion */
diff --git a/src/coreclr/jit/gcinfo.cpp b/src/coreclr/jit/gcinfo.cpp
index 1b4d50fe875..cc8e1cd585f 100644
--- a/src/coreclr/jit/gcinfo.cpp
+++ b/src/coreclr/jit/gcinfo.cpp
@@ -272,7 +272,6 @@ GCInfo::WriteBarrierForm GCInfo::gcIsWriteBarrierCandidate(GenTree* tgt, GenTree
         case GT_LEA:
             return gcWriteBarrierFormFromTargetAddress(tgt->AsAddrMode()->Base());
 
-        case GT_ARR_ELEM: /* Definitely in the managed heap */
         case GT_CLS_VAR:
             return WBF_BarrierUnchecked;
 
diff --git a/src/coreclr/jit/gentree.h b/src/coreclr/jit/gentree.h
index b0439564688..c12e46f02bd 100644
--- a/src/coreclr/jit/gentree.h
+++ b/src/coreclr/jit/gentree.h
@@ -5366,9 +5366,9 @@ struct GenTreeBoundsChk : public GenTree
     }
 };
 
-// gtArrElem -- general array element (GT_ARR_ELEM), for non "SZ_ARRAYS"
-//              -- multidimensional arrays, or 1-d arrays with non-zero lower bounds.
-
+// GenTreeArrElem - bounds checked address (byref) of a general array element,
+//    for multidimensional arrays, or 1-d arrays with non-zero lower bounds.
+//
 struct GenTreeArrElem : public GenTree
 {
     GenTree* gtArrObj;
@@ -5384,7 +5384,7 @@ struct GenTreeArrElem : public GenTree
                                  // This has caused VSW 571394.
     var_types gtArrElemType;     // The array element type
 
-    // Requires that "inds" is a pointer to an array of "rank" GenTreePtrs for the indices.
+    // Requires that "inds" is a pointer to an array of "rank" nodes for the indices.
     GenTreeArrElem(
         var_types type, GenTree* arr, unsigned char rank, unsigned char elemSize, var_types elemType, GenTree** inds)
         : GenTree(GT_ARR_ELEM, type), gtArrObj(arr), gtArrRank(rank), gtArrElemSize(elemSize), gtArrElemType(elemType)
diff --git a/src/coreclr/jit/morph.cpp b/src/coreclr/jit/morph.cpp
index 2b40d8548c6..9f734adaa71 100644
--- a/src/coreclr/jit/morph.cpp
+++ b/src/coreclr/jit/morph.cpp
@@ -639,7 +639,6 @@ OPTIMIZECAST:
                             case GT_IND:
                             case GT_CLS_VAR:
                             case GT_LCL_FLD:
-                            case GT_ARR_ELEM:
                                 oper->gtType = dstType;
                                 // We're changing the type here so we need to update the VN;
                                 // in other cases we discard the cast without modifying oper