Improve liveness for 'STORE_BLK(lcl_var)'. (#48797)

* improve liveness for STORE_BLK

* Improve code for `RehomeArgForFastTailCall`.

* Delete an unnecessary change

While reviewing this change again I found that `fgMarkUseDef` should be called when we visit the local itself, the diffs that I saw from this change were because the LCL_VAR was not marked as `GTF_VAR_DEF`. Now the lclVar is marked as `GTF_VAR_DEF` so we don't need this extra logic.

diff --git a/src/coreclr/jit/compiler.h b/src/coreclr/jit/compiler.h
index e6d386e..64635e1 100644 (file)
--- a/src/coreclr/jit/compiler.h
+++ b/src/coreclr/jit/compiler.h
@@ -2694,6 +2694,8 @@ public:
 
     GenTree* gtNewOneConNode(var_types type);
 
+    GenTreeLclVar* gtNewStoreLclVar(unsigned dstLclNum, GenTree* src);
+
 #ifdef FEATURE_SIMD
     GenTree* gtNewSIMDVectorZero(var_types simdType, var_types baseType, unsigned size);
 #endif

diff --git a/src/coreclr/jit/gentree.cpp b/src/coreclr/jit/gentree.cpp
index efc59f9..86303b7 100644 (file)
--- a/src/coreclr/jit/gentree.cpp
+++ b/src/coreclr/jit/gentree.cpp
@@ -6264,6 +6264,15 @@ GenTree* Compiler::gtNewOneConNode(var_types type)
     return one;
 }
 
+GenTreeLclVar* Compiler::gtNewStoreLclVar(unsigned dstLclNum, GenTree* src)
+{
+    GenTreeLclVar* store = new (this, GT_STORE_LCL_VAR) GenTreeLclVar(GT_STORE_LCL_VAR, src->TypeGet(), dstLclNum);
+    store->gtOp1         = src;
+    store->gtFlags       = (src->gtFlags & GTF_COMMON_MASK);
+    store->gtFlags |= GTF_VAR_DEF | GTF_ASG;
+    return store;
+}
+
 #ifdef FEATURE_SIMD
 //---------------------------------------------------------------------
 // gtNewSIMDVectorZero: create a GT_SIMD node for Vector<T>.Zero

diff --git a/src/coreclr/jit/lower.cpp b/src/coreclr/jit/lower.cpp
index 97ea41c..6641f41 100644 (file)
--- a/src/coreclr/jit/lower.cpp
+++ b/src/coreclr/jit/lower.cpp
@@ -490,10 +490,7 @@ GenTree* Lowering::LowerSwitch(GenTree* node)
         unsigned lclNum               = comp->lvaGrabTemp(true DEBUGARG("Lowering is creating a new local variable"));
         comp->lvaTable[lclNum].lvType = rhs->TypeGet();
 
-        GenTreeLclVar* store = new (comp, GT_STORE_LCL_VAR) GenTreeLclVar(GT_STORE_LCL_VAR, rhs->TypeGet(), lclNum);
-        store->gtOp1         = rhs;
-        store->gtFlags       = (rhs->gtFlags & GTF_COMMON_MASK);
-        store->gtFlags |= GTF_VAR_DEF;
+        GenTreeLclVar* store = comp->gtNewStoreLclVar(lclNum, rhs);
 
         switchBBRange.InsertAfter(node, store);
         switchBBRange.Remove(node);
@@ -2067,24 +2064,14 @@ void Lowering::RehomeArgForFastTailCall(unsigned int lclNum,
             comp->lvaTable[tmpLclNum].lvDoNotEnregister = comp->lvaTable[lcl->GetLclNum()].lvDoNotEnregister;
             GenTree* value                              = comp->gtNewLclvNode(lclNum, tmpTyp);
 
-            // TODO-1stClassStructs: This can be simplified with 1st class structs work.
             if (tmpTyp == TYP_STRUCT)
             {
                 comp->lvaSetStruct(tmpLclNum, comp->lvaGetStruct(lclNum), false);
-                GenTree* loc = new (comp, GT_LCL_VAR_ADDR) GenTreeLclVar(GT_LCL_VAR_ADDR, TYP_STRUCT, tmpLclNum);
-                loc->gtType  = TYP_BYREF;
-                GenTreeBlk* storeBlk = new (comp, GT_STORE_BLK)
-                    GenTreeBlk(GT_STORE_BLK, TYP_STRUCT, loc, value, comp->typGetBlkLayout(callerArgDsc->lvExactSize));
-                storeBlk->gtFlags |= GTF_ASG;
-                BlockRange().InsertBefore(insertTempBefore, LIR::SeqTree(comp, storeBlk));
-                LowerNode(storeBlk);
-            }
-            else
-            {
-                GenTree* assignExpr = comp->gtNewTempAssign(tmpLclNum, value);
-                ContainCheckRange(value, assignExpr);
-                BlockRange().InsertBefore(insertTempBefore, LIR::SeqTree(comp, assignExpr));
             }
+            GenTreeLclVar* storeLclVar = comp->gtNewStoreLclVar(tmpLclNum, value);
+            ContainCheckRange(value, storeLclVar);
+            BlockRange().InsertBefore(insertTempBefore, LIR::SeqTree(comp, storeLclVar));
+            LowerNode(storeLclVar);
         }
 
         lcl->SetLclNum(tmpLclNum);