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-rw-r--r--lib/Target/MSP430/MSP430ISelDAGToDAG.cpp168
-rw-r--r--test/CodeGen/MSP430/Inst16mm.ll1
-rw-r--r--test/CodeGen/MSP430/Inst8mm.ll1
3 files changed, 149 insertions, 21 deletions
diff --git a/lib/Target/MSP430/MSP430ISelDAGToDAG.cpp b/lib/Target/MSP430/MSP430ISelDAGToDAG.cpp
index 550c46897c4..4b6a83c7dda 100644
--- a/lib/Target/MSP430/MSP430ISelDAGToDAG.cpp
+++ b/lib/Target/MSP430/MSP430ISelDAGToDAG.cpp
@@ -65,6 +65,9 @@ namespace {
return "MSP430 DAG->DAG Pattern Instruction Selection";
}
+ bool IsLegalAndProfitableToFold(SDNode *N, SDNode *U,
+ SDNode *Root) const;
+
virtual bool
SelectInlineAsmMemoryOperand(const SDValue &Op, char ConstraintCode,
std::vector<SDValue> &OutOps);
@@ -73,6 +76,7 @@ namespace {
#include "MSP430GenDAGISel.inc"
private:
+ DenseMap<SDNode*, SDNode*> RMWStores;
void PreprocessForRMW();
SDNode *Select(SDValue Op);
bool SelectAddr(SDValue Op, SDValue Addr, SDValue &Base, SDValue &Disp);
@@ -139,7 +143,6 @@ bool MSP430DAGToDAGISel::SelectAddr(SDValue Op, SDValue Addr,
return true;
}
-
bool MSP430DAGToDAGISel::
SelectInlineAsmMemoryOperand(const SDValue &Op, char ConstraintCode,
std::vector<SDValue> &OutOps) {
@@ -157,6 +160,42 @@ SelectInlineAsmMemoryOperand(const SDValue &Op, char ConstraintCode,
return false;
}
+bool MSP430DAGToDAGISel::IsLegalAndProfitableToFold(SDNode *N, SDNode *U,
+ SDNode *Root) const {
+ if (OptLevel == CodeGenOpt::None) return false;
+
+ /// RMW preprocessing creates the following code:
+ /// [Load1]
+ /// ^ ^
+ /// | \
+ /// | \
+ /// [Load2] |
+ /// ^ ^ |
+ /// | | |
+ /// | \-|
+ /// | |
+ /// | [Op]
+ /// | ^
+ /// | |
+ /// \ /
+ /// \ /
+ /// [Store]
+ ///
+ /// The path Store => Load2 => Load1 is via chain. Note that in general it is
+ /// not allowed to fold Load1 into Op (and Store) since it will creates a
+ /// cycle. However, this is perfectly legal for the loads moved below the
+ /// TokenFactor by PreprocessForRMW. Query the map Store => Load1 (created
+ /// during preprocessing) to determine whether it's legal to introduce such
+ /// "cycle" for a moment.
+ DenseMap<SDNode*, SDNode*>::iterator I = RMWStores.find(Root);
+ if (I != RMWStores.end() && I->second == N)
+ return true;
+
+ // Proceed to 'generic' cycle finder code
+ return SelectionDAGISel::IsLegalAndProfitableToFold(N, U, Root);
+}
+
+
/// MoveBelowTokenFactor - Replace TokenFactor operand with load's chain operand
/// and move load below the TokenFactor. Replace store's chain operand with
/// load's chain result.
@@ -176,11 +215,43 @@ static void MoveBelowTokenFactor(SelectionDAG *CurDAG, SDValue Load,
Store.getOperand(2), Store.getOperand(3));
}
-/// isRMWLoad - Return true if N is a load that's part of RMW sub-DAG.
-/// The chain produced by the load must only be used by the store's chain
-/// operand, otherwise this may produce a cycle in the DAG.
-static bool isRMWLoad(SDValue N, SDValue Chain, SDValue Address,
- SDValue &Load) {
+/// MoveBelowTokenFactor2 - Replace TokenFactor operand with load's chain operand
+/// and move load below the TokenFactor. Replace store's chain operand with
+/// load's chain result. This a version which sinks two loads below token factor.
+/// Look into PreprocessForRMW comments for explanation of transform.
+static void MoveBelowTokenFactor2(SelectionDAG *CurDAG,
+ SDValue Load1, SDValue Load2,
+ SDValue Store, SDValue TF) {
+ SmallVector<SDValue, 4> Ops;
+ for (unsigned i = 0, e = TF.getNode()->getNumOperands(); i != e; ++i) {
+ SDNode* N = TF.getOperand(i).getNode();
+ if (Load2.getNode() == N)
+ Ops.push_back(Load2.getOperand(0));
+ else if (Load1.getNode() != N)
+ Ops.push_back(TF.getOperand(i));
+ }
+
+ SDValue NewTF = SDValue(CurDAG->MorphNodeTo(TF.getNode(),
+ TF.getOpcode(),
+ TF.getNode()->getVTList(),
+ &Ops[0], Ops.size()), TF.getResNo());
+ SDValue NewLoad2 = CurDAG->UpdateNodeOperands(Load2, NewTF,
+ Load2.getOperand(1),
+ Load2.getOperand(2));
+
+ SDValue NewLoad1 = CurDAG->UpdateNodeOperands(Load1, NewLoad2.getValue(1),
+ Load1.getOperand(1),
+ Load1.getOperand(2));
+
+ CurDAG->UpdateNodeOperands(Store,
+ NewLoad1.getValue(1),
+ Store.getOperand(1),
+ Store.getOperand(2), Store.getOperand(3));
+}
+
+/// isAllowedToSink - return true if N a load which can be moved below token
+/// factor. Basically, the load should be non-volatile and has single use.
+static bool isLoadAllowedToSink(SDValue N, SDValue Chain) {
if (N.getOpcode() == ISD::BIT_CONVERT)
N = N.getOperand(0);
@@ -194,10 +265,19 @@ static bool isRMWLoad(SDValue N, SDValue Chain, SDValue Address,
if (ExtType != ISD::NON_EXTLOAD && ExtType != ISD::EXTLOAD)
return false;
- if (N.hasOneUse() &&
- LD->hasNUsesOfValue(1, 1) &&
- N.getOperand(1) == Address &&
- LD->isOperandOf(Chain.getNode())) {
+ return (N.hasOneUse() &&
+ LD->hasNUsesOfValue(1, 1) &&
+ LD->isOperandOf(Chain.getNode()));
+}
+
+
+/// isRMWLoad - Return true if N is a load that's part of RMW sub-DAG.
+/// The chain produced by the load must only be used by the store's chain
+/// operand, otherwise this may produce a cycle in the DAG.
+static bool isRMWLoad(SDValue N, SDValue Chain, SDValue Address,
+ SDValue &Load) {
+ if (isLoadAllowedToSink(N, Chain) &&
+ N.getOperand(1) == Address) {
Load = N;
return true;
}
@@ -244,6 +324,34 @@ static bool isRMWLoad(SDValue N, SDValue Chain, SDValue Address,
/// \ /
/// \ /
/// [Store]
+///
+/// We also recognize the case where second operand of Op is load as well and
+/// move it below token factor as well creating DAG as follows:
+///
+/// [Load chain]
+/// ^
+/// |
+/// [TokenFactor]
+/// ^
+/// |
+/// [Load1]
+/// ^ ^
+/// | \
+/// | \
+/// [Load2] |
+/// ^ ^ |
+/// | | |
+/// | \-|
+/// | |
+/// | [Op]
+/// | ^
+/// | |
+/// \ /
+/// \ /
+/// [Store]
+///
+/// This allows selection of mem-mem instructions. Yay!
+
void MSP430DAGToDAGISel::PreprocessForRMW() {
for (SelectionDAG::allnodes_iterator I = CurDAG->allnodes_begin(),
E = CurDAG->allnodes_end(); I != E; ++I) {
@@ -261,8 +369,8 @@ void MSP430DAGToDAGISel::PreprocessForRMW() {
!N1.hasOneUse())
continue;
- bool RModW = false;
- SDValue Load;
+ unsigned RModW = 0;
+ SDValue Load1, Load2;
unsigned Opcode = N1.getNode()->getOpcode();
switch (Opcode) {
case ISD::ADD:
@@ -273,23 +381,44 @@ void MSP430DAGToDAGISel::PreprocessForRMW() {
case ISD::ADDE: {
SDValue N10 = N1.getOperand(0);
SDValue N11 = N1.getOperand(1);
- RModW = isRMWLoad(N10, Chain, N2, Load);
- if (!RModW)
- RModW = isRMWLoad(N11, Chain, N2, Load);
+ if (isRMWLoad(N10, Chain, N2, Load1)) {
+ if (isLoadAllowedToSink(N11, Chain)) {
+ Load2 = N11;
+ RModW = 2;
+ } else
+ RModW = 1;
+ } else if (isRMWLoad(N11, Chain, N2, Load1)) {
+ if (isLoadAllowedToSink(N10, Chain)) {
+ Load2 = N10;
+ RModW = 2;
+ } else
+ RModW = 1;
+ }
break;
}
case ISD::SUB:
case ISD::SUBC:
case ISD::SUBE: {
SDValue N10 = N1.getOperand(0);
- RModW = isRMWLoad(N10, Chain, N2, Load);
+ SDValue N11 = N1.getOperand(1);
+ if (isRMWLoad(N10, Chain, N2, Load1)) {
+ if (isLoadAllowedToSink(N11, Chain)) {
+ Load2 = N11;
+ RModW = 2;
+ } else
+ RModW = 1;
+ }
break;
}
}
- if (RModW) {
- MoveBelowTokenFactor(CurDAG, Load, SDValue(I, 0), Chain);
- ++NumLoadMoved;
+ NumLoadMoved += RModW;
+ if (RModW == 1)
+ MoveBelowTokenFactor(CurDAG, Load1, SDValue(I, 0), Chain);
+ else if (RModW == 2) {
+ MoveBelowTokenFactor2(CurDAG, Load1, Load2, SDValue(I, 0), Chain);
+ SDNode* Store = I;
+ RMWStores[Store] = Load2.getNode();
}
}
}
@@ -318,6 +447,7 @@ void MSP430DAGToDAGISel::InstructionSelect() {
DEBUG(errs() << "===== Instruction selection ends:\n");
CurDAG->RemoveDeadNodes();
+ RMWStores.clear();
}
SDNode *MSP430DAGToDAGISel::Select(SDValue Op) {
diff --git a/test/CodeGen/MSP430/Inst16mm.ll b/test/CodeGen/MSP430/Inst16mm.ll
index 5fefead14bd..510afe37349 100644
--- a/test/CodeGen/MSP430/Inst16mm.ll
+++ b/test/CodeGen/MSP430/Inst16mm.ll
@@ -1,5 +1,4 @@
; RUN: llc -march=msp430 < %s | FileCheck %s
-; XFAIL: *
target datalayout = "e-p:16:8:8-i8:8:8-i16:8:8-i32:8:8"
target triple = "msp430-generic-generic"
@foo = common global i16 0, align 2
diff --git a/test/CodeGen/MSP430/Inst8mm.ll b/test/CodeGen/MSP430/Inst8mm.ll
index 4b0607e670d..a2987ac9b46 100644
--- a/test/CodeGen/MSP430/Inst8mm.ll
+++ b/test/CodeGen/MSP430/Inst8mm.ll
@@ -1,5 +1,4 @@
; RUN: llc -march=msp430 < %s | FileCheck %s
-; XFAIL: *
target datalayout = "e-p:16:8:8-i8:8:8-i16:8:8-i32:8:8"
target triple = "msp430-generic-generic"
generated by cgit v1.2.3 (git 2.25.1) at 2024-06-12 18:54:01 +0000