Delete "lvPromotedStruct" (dotnet#74702)

In all cases where it was used, "lvPromoted" is a better check.

src/coreclr/jit/assertionprop.cpp

@@ -3612,7 +3612,7 @@ GenTree* Compiler::optCopyAssertionProp(AssertionDsc*        curAssertion,
     //
     if (tree->OperIs(GT_LCL_FLD))
     {
-        if (copyVarDsc->IsEnregisterableLcl() || copyVarDsc->lvPromotedStruct())
+        if (copyVarDsc->IsEnregisterableLcl() || copyVarDsc->lvPromoted)
         {
             return nullptr;
         }

src/coreclr/jit/compiler.h

@@ -981,23 +981,7 @@ class LclVarDsc
         lvStkOffs = offset;
     }
 
-    unsigned lvExactSize; // (exact) size of the type in bytes
-
-    // Is this a promoted struct?
-    // This method returns true only for structs (including SIMD structs), not for
-    // locals that are split on a 32-bit target.
-    // It is only necessary to use this:
-    //   1) if only structs are wanted, and
-    //   2) if Lowering has already been done.
-    // Otherwise lvPromoted is valid.
-    bool lvPromotedStruct()
-    {
-#if !defined(TARGET_64BIT)
-        return (lvPromoted && !varTypeIsLong(lvType));
-#else  // defined(TARGET_64BIT)
-        return lvPromoted;
-#endif // defined(TARGET_64BIT)
-    }
+    unsigned lvExactSize; // (exact) size of a STRUCT/SIMD/BLK local in bytes.
 
     unsigned lvSize() const;
 

src/coreclr/jit/decomposelongs.cpp

@@ -2131,18 +2131,28 @@ void DecomposeLongs::PromoteLongVars()
                 m_compiler->lvaGrabTemp(false DEBUGARG(bufp)); // Lifetime of field locals might span multiple BBs, so
                                                                // they are long lifetime temps.
 
+            varDsc                       = m_compiler->lvaGetDesc(lclNum);
             LclVarDsc* fieldVarDsc       = m_compiler->lvaGetDesc(varNum);
             fieldVarDsc->lvType          = TYP_INT;
             fieldVarDsc->lvExactSize     = genTypeSize(TYP_INT);
             fieldVarDsc->lvIsStructField = true;
             fieldVarDsc->lvFldOffset     = (unsigned char)(index * genTypeSize(TYP_INT));
             fieldVarDsc->lvFldOrdinal    = (unsigned char)index;
             fieldVarDsc->lvParentLcl     = lclNum;
+
             // Currently we do not support enregistering incoming promoted aggregates with more than one field.
             if (isParam)
             {
                 fieldVarDsc->lvIsParam = true;
                 m_compiler->lvaSetVarDoNotEnregister(varNum DEBUGARG(DoNotEnregisterReason::LongParamField));
+
+#if FEATURE_MULTIREG_ARGS
+                if (varDsc->lvIsRegArg)
+                {
+                    fieldVarDsc->lvIsRegArg = 1; // Longs are never split.
+                    fieldVarDsc->SetArgReg((index == 0) ? varDsc->GetArgReg() : varDsc->GetOtherArgReg());
+                }
+#endif // FEATURE_MULTIREG_ARGS
             }
         }
     }

src/coreclr/jit/lclvars.cpp

@@ -4926,7 +4926,7 @@ void Compiler::lvaComputeRefCounts(bool isRecompute, bool setSlotNumbers)
             //
             // This was formerly done during RCS_EARLY counting,
             // and we did not used to reset counts like we do now.
-            if (varDsc->lvIsStructField)
+            if (varDsc->lvIsStructField && varTypeIsStruct(lvaGetDesc(varDsc->lvParentLcl)))
             {
                 varDsc->incRefCnts(BB_UNITY_WEIGHT, this);
             }
@@ -5740,7 +5740,7 @@ void Compiler::lvaUpdateArgsWithInitialReg()
     {
         LclVarDsc* varDsc = lvaGetDesc(lclNum);
 
-        if (varDsc->lvPromotedStruct())
+        if (varDsc->lvPromoted)
         {
             for (unsigned fieldVarNum = varDsc->lvFieldLclStart;
                  fieldVarNum < varDsc->lvFieldLclStart + varDsc->lvFieldCnt; ++fieldVarNum)
@@ -6041,7 +6041,7 @@ int Compiler::lvaAssignVirtualFrameOffsetToArg(unsigned lclNum,
     // For struct promoted parameters we need to set the offsets for the field lclVars.
     //
     // For a promoted struct we also assign the struct fields stack offset
-    if (varDsc->lvPromotedStruct())
+    if (varDsc->lvPromoted)
     {
         unsigned firstFieldNum = varDsc->lvFieldLclStart;
         int      offset        = varDsc->GetStackOffset();
@@ -6345,17 +6345,7 @@ int Compiler::lvaAssignVirtualFrameOffsetToArg(unsigned lclNum,
     // For a dependent promoted struct we also assign the struct fields stack offset
     CLANG_FORMAT_COMMENT_ANCHOR;
 
-#if !defined(TARGET_64BIT)
-    if ((varDsc->TypeGet() == TYP_LONG) && varDsc->lvPromoted)
-    {
-        noway_assert(varDsc->lvFieldCnt == 2);
-        fieldVarNum = varDsc->lvFieldLclStart;
-        lvaTable[fieldVarNum].SetStackOffset(varDsc->GetStackOffset());
-        lvaTable[fieldVarNum + 1].SetStackOffset(varDsc->GetStackOffset() + genTypeSize(TYP_INT));
-    }
-    else
-#endif // !defined(TARGET_64BIT)
-        if (varDsc->lvPromotedStruct())
+    if (varDsc->lvPromoted)
     {
         unsigned firstFieldNum = varDsc->lvFieldLclStart;
         for (unsigned i = 0; i < varDsc->lvFieldCnt; i++)
@@ -7105,10 +7095,10 @@ void Compiler::lvaAssignVirtualFrameOffsetsToLocals()
             // Reserve the stack space for this variable
             stkOffs = lvaAllocLocalAndSetVirtualOffset(lclNum, lvaLclSize(lclNum), stkOffs);
 #if defined(TARGET_ARMARCH) || defined(TARGET_LOONGARCH64)
-            // If we have an incoming register argument that has a struct promoted field
-            // then we need to copy the lvStkOff (the stack home) from the reg arg to the field lclvar
+            // If we have an incoming register argument that has a promoted field then we
+            // need to copy the lvStkOff (the stack home) from the reg arg to the field lclvar
             //
-            if (varDsc->lvIsRegArg && varDsc->lvPromotedStruct())
+            if (varDsc->lvIsRegArg && varDsc->lvPromoted)
             {
                 unsigned firstFieldNum = varDsc->lvFieldLclStart;
                 for (unsigned i = 0; i < varDsc->lvFieldCnt; i++)
@@ -7117,20 +7107,7 @@ void Compiler::lvaAssignVirtualFrameOffsetsToLocals()
                     fieldVarDsc->SetStackOffset(varDsc->GetStackOffset() + fieldVarDsc->lvFldOffset);
                 }
             }
-#ifdef TARGET_ARM
-            // If we have an incoming register argument that has a promoted long
-            // then we need to copy the lvStkOff (the stack home) from the reg arg to the field lclvar
-            //
-            else if (varDsc->lvIsRegArg && varDsc->lvPromoted)
-            {
-                assert(varTypeIsLong(varDsc) && (varDsc->lvFieldCnt == 2));
-
-                unsigned fieldVarNum = varDsc->lvFieldLclStart;
-                lvaTable[fieldVarNum].SetStackOffset(varDsc->GetStackOffset());
-                lvaTable[fieldVarNum + 1].SetStackOffset(varDsc->GetStackOffset() + 4);
-            }
-#endif // TARGET_ARM
-#endif // TARGET_ARM64 || TARGET_LOONGARCH64
+#endif // defined(TARGET_ARMARCH) || defined(TARGET_LOONGARCH64)
         }
     }
 

src/coreclr/jit/lsrabuild.cpp

@@ -2044,11 +2044,6 @@ void LinearScan::UpdateRegStateForStructArg(LclVarDsc* argDsc)
 //    The argument is live on entry to the function
 //    (or is untracked and therefore assumed live)
 //
-// Notes:
-//    This relies on a method in regAlloc.cpp that is shared between LSRA
-//    and regAlloc.  It is further abstracted here because regState is updated
-//    separately for tracked and untracked variables in LSRA.
-//
 void LinearScan::updateRegStateForArg(LclVarDsc* argDsc)
 {
 #if defined(UNIX_AMD64_ABI) || defined(TARGET_LOONGARCH64)
@@ -2204,7 +2199,7 @@ void LinearScan::buildIntervals()
             RefPosition* pos = newRefPosition(interval, MinLocation, RefTypeParamDef, nullptr, mask);
             pos->setRegOptional(true);
         }
-        else if (varTypeIsStruct(argDsc->lvType))
+        else if (argDsc->lvPromoted)
         {
             for (unsigned fieldVarNum = argDsc->lvFieldLclStart;
                  fieldVarNum < argDsc->lvFieldLclStart + argDsc->lvFieldCnt; ++fieldVarNum)
@@ -2236,7 +2231,7 @@ void LinearScan::buildIntervals()
     {
         LclVarDsc* argDsc = compiler->lvaGetDesc(argNum);
 
-        if (argDsc->lvPromotedStruct())
+        if (argDsc->lvPromoted)
         {
             for (unsigned fieldVarNum = argDsc->lvFieldLclStart;
                  fieldVarNum < argDsc->lvFieldLclStart + argDsc->lvFieldCnt; ++fieldVarNum)

src/coreclr/jit/rationalize.cpp

@@ -126,7 +126,7 @@ void Rationalizer::RewriteSIMDIndir(LIR::Use& use)
 
             comp->lvaSetVarDoNotEnregister(lclNum DEBUGARG(DoNotEnregisterReason::LocalField));
         }
-        if (varDsc->lvPromotedStruct())
+        if (varDsc->lvPromoted)
         {
             comp->lvaSetVarDoNotEnregister(lclNum DEBUGARG(DoNotEnregisterReason::BlockOp));
         }