Merge pull request dotnet#11 from pgavlin/LIRFixes

Fix a few bugs/diffs in the LIR backend.

Author: pgavlin

src/jit/lir.cpp

@@ -506,15 +506,26 @@ GenTree* LIR::Range::FirstNonPhiNode() const
 {
     assert(IsValid());
 
-    for (GenTree* node : *this)
+    GenTree* node, *end;
+    for (node = Begin(), end = End(); node != end; node = node->gtNext)
     {
-        if ((node->OperGet() != GT_PHI_ARG) && (node->OperGet() != GT_PHI) && !node->IsPhiDefn())
+        if (node->OperGet() == GT_PHI_ARG)
         {
-            return node;
+            continue;
         }
+        else if (node->OperGet() == GT_PHI)
+        {
+            continue;
+        }
+        else if (node->IsPhiDefn())
+        {
+            continue;
+        }
+
+        break;
     }
 
-    return End();
+    return node;
 }
 
 //------------------------------------------------------------------------
@@ -526,15 +537,22 @@ GenTree* LIR::Range::FirstNonPhiOrCatchArgNode() const
 {
     assert(IsValid());
 
-    for (GenTree* node = FirstNonPhiNode(), *end = End(); node != end; node = node->gtNext)
+    GenTree* node, *end;
+    for (node = FirstNonPhiNode(), end = End(); node != end; node = node->gtNext)
     {
-        if ((node->OperGet() == GT_STORE_LCL_VAR) && (node->gtOp.gtOp1->OperGet() == GT_CATCH_ARG))
+        if (node->OperGet() == GT_CATCH_ARG)
         {
-            return node->gtNext;
+            continue;
         }
+        else if ((node->OperGet() == GT_STORE_LCL_VAR) && (node->gtGetOp1()->OperGet() == GT_CATCH_ARG))
+        {
+            continue;
+        }
+
+        break;
     }
 
-    return End();
+    return node;
 }
 
 //------------------------------------------------------------------------
@@ -1091,6 +1109,8 @@ bool LIR::Range::CheckLIR(Compiler* compiler, bool checkUnusedValues) const
         // Verify that the node is allowed in LIR.
         assert(node->IsLIR());
 
+        // TODO: validate catch arg stores
+
         // Check that all phi nodes (if any) occur at the start of the range.
         if ((node->OperGet() == GT_PHI_ARG) || (node->OperGet() == GT_PHI) || node->IsPhiDefn())
         {

src/jit/lower.cpp

@@ -2330,8 +2330,7 @@ void Lowering::InsertPInvokeMethodProlog()
     }
 
     comp->fgMorphTree(store);
-    firstBlockRange.InsertAfter(LIR::SeqTree(comp, store), insertionPoint);
-    insertionPoint = store;
+    firstBlockRange.InsertBefore(LIR::SeqTree(comp, store), insertionPoint);
 
     DISPTREE(store);
 
@@ -2345,8 +2344,7 @@ void Lowering::InsertPInvokeMethodProlog()
                                                     callFrameInfo.offsetOfCallSiteSP);
     storeSP->gtOp1 = PhysReg(REG_SPBASE);
 
-    firstBlockRange.InsertAfter(LIR::SeqTree(comp, storeSP), insertionPoint);
-    insertionPoint = storeSP;
+    firstBlockRange.InsertBefore(LIR::SeqTree(comp, storeSP), insertionPoint);
 
     DISPTREE(storeSP);
 
@@ -2360,8 +2358,7 @@ void Lowering::InsertPInvokeMethodProlog()
                                                     callFrameInfo.offsetOfCalleeSavedFP);
     storeFP->gtOp1 = PhysReg(REG_FPBASE);
 
-    firstBlockRange.InsertAfter(LIR::SeqTree(comp, storeFP), insertionPoint);
-    insertionPoint = storeFP;
+    firstBlockRange.InsertBefore(LIR::SeqTree(comp, storeFP), insertionPoint);
 
     DISPTREE(storeFP);
 
@@ -2372,7 +2369,7 @@ void Lowering::InsertPInvokeMethodProlog()
         // Push a frame - if we are NOT in an IL stub, this is done right before the call
         // The init routine sets InlinedCallFrame's m_pNext, so we just set the thead's top-of-stack
         GenTree* frameUpd = CreateFrameLinkUpdate(PushFrame);
-        firstBlockRange.InsertAfter(LIR::SeqTree(comp, frameUpd), insertionPoint);
+        firstBlockRange.InsertBefore(LIR::SeqTree(comp, frameUpd), insertionPoint);
         DISPTREE(frameUpd);
     }
 }

src/jit/rationalize.cpp

@@ -1356,8 +1356,6 @@ Compiler::fgWalkResult Rationalizer::RewriteNode(GenTree** useEdge, ArrayStack<G
 #endif // FEATURE_SIMD
 
     default:
-        // Ensure that the LIR flags are clear.
-        node->gtLIRFlags = LIR::Flags::None;
         break;
     }
 
@@ -1392,6 +1390,9 @@ void Rationalizer::DoPhase()
         // This needs to be done before the transition to LIR because it relies on the use
         // of fgMorphArgs, which is designed to operate on HIR. Once this is done for a
         // particular statement, link that statement's nodes into the current basic block.
+        //
+        // This walk also clears the GTF_VAR_USEDEF bit on locals, which is not necessary
+        // in the backend.
         GenTree* lastNodeInPreviousStatement = nullptr;
         for (GenTreeStmt* statement = firstStatement; statement != nullptr; statement = statement->getNextStmt())
         {
@@ -1414,6 +1415,10 @@ void Rationalizer::DoPhase()
 
                         walkData->compiler->fgFixupIfCallArg(walkData->parentStack, node, *use);
                     }
+                    else if (node->OperIsLocal())
+                    {
+                        node->gtFlags &= ~GTF_VAR_USEDEF;
+                    }
 
                     return Compiler::WALK_CONTINUE;
                 },