From 966fd37ba574930658c83710952df5d00a8fed92 Mon Sep 17 00:00:00 2001 From: Evan Cheng Date: Mon, 11 Sep 2006 02:24:43 +0000 Subject: [PATCH] 1) With X86 lowering change, the following can no longer happen since the branch's chain is also produced by cmp. [ch, r : ld] ^ ^ | | [XX]--/ \- [flag : cmp] ^ ^ | | \---[br flag]- Remove an isel check which prevents loads from being folded into cmp / test instructions. 2) Whenever possible, delete a selected node to allow more load folding opportunities. Note not all nodes can be deleted after it has been selected. Some may have simply morphed; some have not changed at all (e.g. EntryToken). git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@30242 91177308-0d34-0410-b5e6-96231b3b80d8 --- utils/TableGen/DAGISelEmitter.cpp | 35 ++++++++++++++----------------- 1 file changed, 16 insertions(+), 19 deletions(-) diff --git a/utils/TableGen/DAGISelEmitter.cpp b/utils/TableGen/DAGISelEmitter.cpp index 53934fa6021..c8dd50e9c44 100644 --- a/utils/TableGen/DAGISelEmitter.cpp +++ b/utils/TableGen/DAGISelEmitter.cpp @@ -2246,24 +2246,6 @@ public: emitCheck(RootName + ".hasOneUse()"); EmittedUseCheck = true; if (NodeHasChain) { - // FIXME: Don't fold if 1) the parent node writes a flag, 2) the node - // has a chain use. - // This a workaround for this problem: - // - // [ch, r : ld] - // ^ ^ - // | | - // [XX]--/ \- [flag : cmp] - // ^ ^ - // | | - // \---[br flag]- - // - // cmp + br should be considered as a single node as they are flagged - // together. So, if the ld is folded into the cmp, the XX node in the - // graph is now both an operand and a use of the ld/cmp/br node. - if (NodeHasProperty(P, SDNodeInfo::SDNPOutFlag, ISE)) - emitCheck(ParentName + ".Val->isOnlyUse(" + RootName + ".Val)"); - // If the immediate use can somehow reach this node through another // path, then can't fold it either or it will create a cycle. // e.g. In the following diagram, XX can reach ld through YY. If @@ -3629,6 +3611,16 @@ OS << " unsigned NumKilled = ISelKilled.size();\n"; OS << " RemoveKilled();\n"; OS << "}\n\n"; + OS << "void DeleteNode(SDNode *N) {\n"; + OS << " CurDAG->DeleteNode(N);\n"; + OS << " for (SDNode::op_iterator I = N->op_begin(), E = N->op_end(); " + << "I != E; ++I) {\n"; + OS << " SDNode *Operand = I->Val;\n"; + OS << " if (Operand->use_empty())\n"; + OS << " DeleteNode(Operand);\n"; + OS << " }\n"; + OS << "}\n"; + OS << "// SelectRoot - Top level entry to DAG isel.\n"; OS << "SDOperand SelectRoot(SDOperand Root) {\n"; OS << " SelectRootInit();\n"; @@ -3649,7 +3641,12 @@ OS << " unsigned NumKilled = ISelKilled.size();\n"; OS << " ISelQueue.pop_back();\n"; OS << " if (!isSelected(Node->getNodeId())) {\n"; OS << " SDNode *ResNode = Select(SDOperand(Node, 0));\n"; - OS << " if (ResNode && ResNode != Node) ReplaceUses(Node, ResNode);\n"; + OS << " if (ResNode != Node) {\n"; + OS << " if (ResNode)\n"; + OS << " ReplaceUses(Node, ResNode);\n"; + OS << " if (Node->use_empty()) // Don't delete EntryToken, etc.\n"; + OS << " DeleteNode(Node);\n"; + OS << " }\n"; OS << " }\n"; OS << " }\n"; OS << "\n"; -- 2.34.1