Teach DAGCombine to fold constant offsets into GlobalAddress nodes,
and add a TargetLowering hook for it to use to determine when this
is legal (i.e. not in PIC mode, etc.)
This allows instruction selection to emit folded constant offsets
in more cases, such as the included testcase, eliminating the need
for explicit arithmetic instructions.
This eliminates the need for the C++ code in X86ISelDAGToDAG.cpp
that attempted to achieve the same effect, but wasn't as effective.
Also, fix handling of offsets in GlobalAddressSDNodes in several
places, including changing GlobalAddressSDNode's offset from
int to int64_t.
The Mips, Alpha, Sparc, and CellSPU targets appear to be
unaware of GlobalAddress offsets currently, so set the hook to
false on those targets.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@57748 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Target/X86/X86ISelDAGToDAG.cpp b/lib/Target/X86/X86ISelDAGToDAG.cpp
index cf83e68..6735f1d 100644
--- a/lib/Target/X86/X86ISelDAGToDAG.cpp
+++ b/lib/Target/X86/X86ISelDAGToDAG.cpp
@@ -759,6 +759,7 @@
/// addressing mode.
bool X86DAGToDAGISel::MatchAddress(SDValue N, X86ISelAddressMode &AM,
bool isRoot, unsigned Depth) {
+ bool is64Bit = Subtarget->is64Bit();
DOUT << "MatchAddress: "; DEBUG(AM.dump());
// Limit recursion.
if (Depth > 5)
@@ -768,7 +769,7 @@
if (AM.isRIPRel) {
if (!AM.ES && AM.JT != -1 && N.getOpcode() == ISD::Constant) {
int64_t Val = cast<ConstantSDNode>(N)->getSExtValue();
- if (isInt32(AM.Disp + Val)) {
+ if (!is64Bit || isInt32(AM.Disp + Val)) {
AM.Disp += Val;
return false;
}
@@ -783,7 +784,7 @@
default: break;
case ISD::Constant: {
int64_t Val = cast<ConstantSDNode>(N)->getSExtValue();
- if (isInt32(AM.Disp + Val)) {
+ if (!is64Bit || isInt32(AM.Disp + Val)) {
AM.Disp += Val;
return false;
}
@@ -791,10 +792,9 @@
}
case X86ISD::Wrapper: {
-DOUT << "Wrapper: 64bit " << Subtarget->is64Bit();
-DOUT << " AM "; DEBUG(AM.dump()); DOUT << "\n";
-DOUT << "AlreadySelected " << AlreadySelected << "\n";
- bool is64Bit = Subtarget->is64Bit();
+ DOUT << "Wrapper: 64bit " << is64Bit;
+ DOUT << " AM "; DEBUG(AM.dump()); DOUT << "\n";
+ DOUT << "AlreadySelected " << AlreadySelected << "\n";
// Under X86-64 non-small code model, GV (and friends) are 64-bits.
// Also, base and index reg must be 0 in order to use rip as base.
if (is64Bit && (TM.getCodeModel() != CodeModel::Small ||
@@ -808,17 +808,21 @@
if (!AlreadySelected || (AM.Base.Reg.getNode() && AM.IndexReg.getNode())) {
SDValue N0 = N.getOperand(0);
if (GlobalAddressSDNode *G = dyn_cast<GlobalAddressSDNode>(N0)) {
- GlobalValue *GV = G->getGlobal();
- AM.GV = GV;
- AM.Disp += G->getOffset();
- AM.isRIPRel = TM.symbolicAddressesAreRIPRel();
- return false;
+ if (!is64Bit || isInt32(AM.Disp + G->getOffset())) {
+ GlobalValue *GV = G->getGlobal();
+ AM.GV = GV;
+ AM.Disp += G->getOffset();
+ AM.isRIPRel = TM.symbolicAddressesAreRIPRel();
+ return false;
+ }
} else if (ConstantPoolSDNode *CP = dyn_cast<ConstantPoolSDNode>(N0)) {
- AM.CP = CP->getConstVal();
- AM.Align = CP->getAlignment();
- AM.Disp += CP->getOffset();
- AM.isRIPRel = TM.symbolicAddressesAreRIPRel();
- return false;
+ if (!is64Bit || isInt32(AM.Disp + CP->getOffset())) {
+ AM.CP = CP->getConstVal();
+ AM.Align = CP->getAlignment();
+ AM.Disp += CP->getOffset();
+ AM.isRIPRel = TM.symbolicAddressesAreRIPRel();
+ return false;
+ }
} else if (ExternalSymbolSDNode *S =dyn_cast<ExternalSymbolSDNode>(N0)) {
AM.ES = S->getSymbol();
AM.isRIPRel = TM.symbolicAddressesAreRIPRel();
@@ -862,7 +866,7 @@
ConstantSDNode *AddVal =
cast<ConstantSDNode>(ShVal.getNode()->getOperand(1));
uint64_t Disp = AM.Disp + (AddVal->getZExtValue() << Val);
- if (isInt32(Disp))
+ if (!is64Bit || isInt32(Disp))
AM.Disp = Disp;
else
AM.IndexReg = ShVal;
@@ -905,7 +909,7 @@
cast<ConstantSDNode>(MulVal.getNode()->getOperand(1));
uint64_t Disp = AM.Disp + AddVal->getZExtValue() *
CN->getZExtValue();
- if (isInt32(Disp))
+ if (!is64Bit || isInt32(Disp))
AM.Disp = Disp;
else
Reg = N.getNode()->getOperand(0);
@@ -944,7 +948,7 @@
// Address could not have picked a GV address for the displacement.
AM.GV == NULL &&
// On x86-64, the resultant disp must fit in 32-bits.
- isInt32(AM.Disp + CN->getSExtValue()) &&
+ (!is64Bit || isInt32(AM.Disp + CN->getSExtValue())) &&
// Check to see if the LHS & C is zero.
CurDAG->MaskedValueIsZero(N.getOperand(0), CN->getAPIntValue())) {
AM.Disp += CN->getZExtValue();
@@ -1248,49 +1252,6 @@
case X86ISD::GlobalBaseReg:
return getGlobalBaseReg();
- case ISD::ADD: {
- // Turn ADD X, c to MOV32ri X+c. This cannot be done with tblgen'd
- // code and is matched first so to prevent it from being turned into
- // LEA32r X+c.
- // In 64-bit small code size mode, use LEA to take advantage of
- // RIP-relative addressing.
- if (TM.getCodeModel() != CodeModel::Small)
- break;
- MVT PtrVT = TLI.getPointerTy();
- SDValue N0 = N.getOperand(0);
- SDValue N1 = N.getOperand(1);
- if (N.getNode()->getValueType(0) == PtrVT &&
- N0.getOpcode() == X86ISD::Wrapper &&
- N1.getOpcode() == ISD::Constant) {
- unsigned Offset = (unsigned)cast<ConstantSDNode>(N1)->getZExtValue();
- SDValue C(0, 0);
- // TODO: handle ExternalSymbolSDNode.
- if (GlobalAddressSDNode *G =
- dyn_cast<GlobalAddressSDNode>(N0.getOperand(0))) {
- C = CurDAG->getTargetGlobalAddress(G->getGlobal(), PtrVT,
- G->getOffset() + Offset);
- } else if (ConstantPoolSDNode *CP =
- dyn_cast<ConstantPoolSDNode>(N0.getOperand(0))) {
- C = CurDAG->getTargetConstantPool(CP->getConstVal(), PtrVT,
- CP->getAlignment(),
- CP->getOffset()+Offset);
- }
-
- if (C.getNode()) {
- if (Subtarget->is64Bit()) {
- SDValue Ops[] = { CurDAG->getRegister(0, PtrVT), getI8Imm(1),
- CurDAG->getRegister(0, PtrVT), C };
- return CurDAG->SelectNodeTo(N.getNode(), X86::LEA64r,
- MVT::i64, Ops, 4);
- } else
- return CurDAG->SelectNodeTo(N.getNode(), X86::MOV32ri, PtrVT, C);
- }
- }
-
- // Other cases are handled by auto-generated code.
- break;
- }
-
case X86ISD::ATOMOR64_DAG:
return SelectAtomic64(Node, X86::ATOMOR6432);
case X86ISD::ATOMXOR64_DAG: