Rename ExpandISelPseudo->FinalizeISel, delay register reservation
This allows targets to make more decisions about reserved registers
after isel. For example, now it should be certain there are calls or
stack objects in the frame or not, which could have been introduced by
legalization.
Patch by Matthias Braun
llvm-svn: 363757
diff --git a/llvm/lib/CodeGen/FinalizeISel.cpp b/llvm/lib/CodeGen/FinalizeISel.cpp
new file mode 100644
index 0000000..772d7f7
--- /dev/null
+++ b/llvm/lib/CodeGen/FinalizeISel.cpp
@@ -0,0 +1,76 @@
+//===-- llvm/CodeGen/FinalizeISel.cpp ---------------------------*- C++ -*-===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+//
+/// This pass expands Pseudo-instructions produced by ISel, fixes register
+/// reservations and may do machine frame information adjustments.
+/// The pseudo instructions are used to allow the expansion to contain control
+/// flow, such as a conditional move implemented with a conditional branch and a
+/// phi, or an atomic operation implemented with a loop.
+//
+//===----------------------------------------------------------------------===//
+
+#include "llvm/CodeGen/MachineFunction.h"
+#include "llvm/CodeGen/MachineFunctionPass.h"
+#include "llvm/CodeGen/Passes.h"
+#include "llvm/CodeGen/TargetLowering.h"
+#include "llvm/CodeGen/TargetSubtargetInfo.h"
+#include "llvm/Support/Debug.h"
+using namespace llvm;
+
+#define DEBUG_TYPE "finalize-isel"
+
+namespace {
+ class FinalizeISel : public MachineFunctionPass {
+ public:
+ static char ID; // Pass identification, replacement for typeid
+ FinalizeISel() : MachineFunctionPass(ID) {}
+
+ private:
+ bool runOnMachineFunction(MachineFunction &MF) override;
+
+ void getAnalysisUsage(AnalysisUsage &AU) const override {
+ MachineFunctionPass::getAnalysisUsage(AU);
+ }
+ };
+} // end anonymous namespace
+
+char FinalizeISel::ID = 0;
+char &llvm::FinalizeISelID = FinalizeISel::ID;
+INITIALIZE_PASS(FinalizeISel, DEBUG_TYPE,
+ "Finalize ISel and expand pseudo-instructions", false, false)
+
+bool FinalizeISel::runOnMachineFunction(MachineFunction &MF) {
+ bool Changed = false;
+ const TargetLowering *TLI = MF.getSubtarget().getTargetLowering();
+
+ // Iterate through each instruction in the function, looking for pseudos.
+ for (MachineFunction::iterator I = MF.begin(), E = MF.end(); I != E; ++I) {
+ MachineBasicBlock *MBB = &*I;
+ for (MachineBasicBlock::iterator MBBI = MBB->begin(), MBBE = MBB->end();
+ MBBI != MBBE; ) {
+ MachineInstr &MI = *MBBI++;
+
+ // If MI is a pseudo, expand it.
+ if (MI.usesCustomInsertionHook()) {
+ Changed = true;
+ MachineBasicBlock *NewMBB = TLI->EmitInstrWithCustomInserter(MI, MBB);
+ // The expansion may involve new basic blocks.
+ if (NewMBB != MBB) {
+ MBB = NewMBB;
+ I = NewMBB->getIterator();
+ MBBI = NewMBB->begin();
+ MBBE = NewMBB->end();
+ }
+ }
+ }
+ }
+
+ TLI->finalizeLowering(MF);
+
+ return Changed;
+}