Lower dynamic stack allocation on mingw32 to separate instruction.
We cannot use a normal call here since it has extra unmodelled side
effects (it changes stack pointer). This should fix PR5292.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@97884 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Target/X86/X86ISelLowering.cpp b/lib/Target/X86/X86ISelLowering.cpp
index 8384ab7..802bedc 100644
--- a/lib/Target/X86/X86ISelLowering.cpp
+++ b/lib/Target/X86/X86ISelLowering.cpp
@@ -6418,24 +6418,13 @@
EVT IntPtr = getPointerTy();
EVT SPTy = Subtarget->is64Bit() ? MVT::i64 : MVT::i32;
- Chain = DAG.getCALLSEQ_START(Chain, DAG.getIntPtrConstant(0, true));
-
Chain = DAG.getCopyToReg(Chain, dl, X86::EAX, Size, Flag);
Flag = Chain.getValue(1);
- SDVTList NodeTys = DAG.getVTList(MVT::Other, MVT::Flag);
- SDValue Ops[] = { Chain,
- DAG.getTargetExternalSymbol("_alloca", IntPtr),
- DAG.getRegister(X86::EAX, IntPtr),
- DAG.getRegister(X86StackPtr, SPTy),
- Flag };
- Chain = DAG.getNode(X86ISD::CALL, dl, NodeTys, Ops, 5);
- Flag = Chain.getValue(1);
+ SDVTList NodeTys = DAG.getVTList(MVT::Other, MVT::Flag);
- Chain = DAG.getCALLSEQ_END(Chain,
- DAG.getIntPtrConstant(0, true),
- DAG.getIntPtrConstant(0, true),
- Flag);
+ Chain = DAG.getNode(X86ISD::MINGW_ALLOCA, dl, NodeTys, Chain, Flag);
+ Flag = Chain.getValue(1);
Chain = DAG.getCopyFromReg(Chain, dl, X86StackPtr, SPTy).getValue(1);
@@ -7741,6 +7730,7 @@
case X86ISD::MUL_IMM: return "X86ISD::MUL_IMM";
case X86ISD::PTEST: return "X86ISD::PTEST";
case X86ISD::VASTART_SAVE_XMM_REGS: return "X86ISD::VASTART_SAVE_XMM_REGS";
+ case X86ISD::MINGW_ALLOCA: return "X86ISD::MINGW_ALLOCA";
}
}
@@ -8410,6 +8400,29 @@
return BB;
}
+MachineBasicBlock *
+X86TargetLowering::EmitLoweredMingwAlloca(MachineInstr *MI,
+ MachineBasicBlock *BB,
+ DenseMap<MachineBasicBlock*, MachineBasicBlock*> *EM) const {
+ const TargetInstrInfo *TII = getTargetMachine().getInstrInfo();
+ DebugLoc DL = MI->getDebugLoc();
+ MachineFunction *F = BB->getParent();
+
+ // The lowering is pretty easy: we're just emitting the call to _alloca. The
+ // non-trivial part is impdef of ESP.
+ // FIXME: The code should be tweaked as soon as we'll try to do codegen for
+ // mingw-w64.
+
+ BuildMI(BB, DL, TII->get(X86::CALLpcrel32))
+ .addExternalSymbol("_alloca")
+ .addReg(X86::EAX, RegState::Implicit)
+ .addReg(X86::ESP, RegState::Implicit)
+ .addReg(X86::EAX, RegState::Define | RegState::Implicit)
+ .addReg(X86::ESP, RegState::Define | RegState::Implicit);
+
+ F->DeleteMachineInstr(MI); // The pseudo instruction is gone now.
+ return BB;
+}
MachineBasicBlock *
X86TargetLowering::EmitInstrWithCustomInserter(MachineInstr *MI,
@@ -8417,6 +8430,8 @@
DenseMap<MachineBasicBlock*, MachineBasicBlock*> *EM) const {
switch (MI->getOpcode()) {
default: assert(false && "Unexpected instr type to insert");
+ case X86::MINGW_ALLOCA:
+ return EmitLoweredMingwAlloca(MI, BB, EM);
case X86::CMOV_GR8:
case X86::CMOV_V1I64:
case X86::CMOV_FR32: