llvm-65816/lib/Target/SystemZ/SystemZTargetMachine.cpp

109 lines
4.3 KiB
C++

//===-- SystemZTargetMachine.cpp - Define TargetMachine for SystemZ -------===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
#include "SystemZTargetMachine.h"
#include "llvm/CodeGen/Passes.h"
#include "llvm/Support/TargetRegistry.h"
#include "llvm/Transforms/Scalar.h"
using namespace llvm;
extern "C" void LLVMInitializeSystemZTarget() {
// Register the target.
RegisterTargetMachine<SystemZTargetMachine> X(TheSystemZTarget);
}
SystemZTargetMachine::SystemZTargetMachine(const Target &T, StringRef TT,
StringRef CPU, StringRef FS,
const TargetOptions &Options,
Reloc::Model RM,
CodeModel::Model CM,
CodeGenOpt::Level OL)
: LLVMTargetMachine(T, TT, CPU, FS, Options, RM, CM, OL),
Subtarget(TT, CPU, FS),
// Make sure that global data has at least 16 bits of alignment by default,
// so that we can refer to it using LARL. We don't have any special
// requirements for stack variables though.
DL("E-p:64:64:64-i1:8:16-i8:8:16-i16:16-i32:32-i64:64"
"-f32:32-f64:64-f128:64-a0:8:16-n32:64"),
InstrInfo(*this), TLInfo(*this), TSInfo(*this),
FrameLowering(*this, Subtarget) {
initAsmInfo();
}
namespace {
/// SystemZ Code Generator Pass Configuration Options.
class SystemZPassConfig : public TargetPassConfig {
public:
SystemZPassConfig(SystemZTargetMachine *TM, PassManagerBase &PM)
: TargetPassConfig(TM, PM) {}
SystemZTargetMachine &getSystemZTargetMachine() const {
return getTM<SystemZTargetMachine>();
}
virtual void addIRPasses() LLVM_OVERRIDE;
virtual bool addInstSelector() LLVM_OVERRIDE;
virtual bool addPreSched2() LLVM_OVERRIDE;
virtual bool addPreEmitPass() LLVM_OVERRIDE;
};
} // end anonymous namespace
void SystemZPassConfig::addIRPasses() {
TargetPassConfig::addIRPasses();
addPass(createPartiallyInlineLibCallsPass());
}
bool SystemZPassConfig::addInstSelector() {
addPass(createSystemZISelDag(getSystemZTargetMachine(), getOptLevel()));
return false;
}
bool SystemZPassConfig::addPreSched2() {
if (getSystemZTargetMachine().getSubtargetImpl()->hasLoadStoreOnCond())
addPass(&IfConverterID);
return true;
}
bool SystemZPassConfig::addPreEmitPass() {
// We eliminate comparisons here rather than earlier because some
// transformations can change the set of available CC values and we
// generally want those transformations to have priority. This is
// especially true in the commonest case where the result of the comparison
// is used by a single in-range branch instruction, since we will then
// be able to fuse the compare and the branch instead.
//
// For example, two-address NILF can sometimes be converted into
// three-address RISBLG. NILF produces a CC value that indicates whether
// the low word is zero, but RISBLG does not modify CC at all. On the
// other hand, 64-bit ANDs like NILL can sometimes be converted to RISBG.
// The CC value produced by NILL isn't useful for our purposes, but the
// value produced by RISBG can be used for any comparison with zero
// (not just equality). So there are some transformations that lose
// CC values (while still being worthwhile) and others that happen to make
// the CC result more useful than it was originally.
//
// Another reason is that we only want to use BRANCH ON COUNT in cases
// where we know that the count register is not going to be spilled.
//
// Doing it so late makes it more likely that a register will be reused
// between the comparison and the branch, but it isn't clear whether
// preventing that would be a win or not.
if (getOptLevel() != CodeGenOpt::None)
addPass(createSystemZElimComparePass(getSystemZTargetMachine()));
if (getOptLevel() != CodeGenOpt::None)
addPass(createSystemZShortenInstPass(getSystemZTargetMachine()));
addPass(createSystemZLongBranchPass(getSystemZTargetMachine()));
return true;
}
TargetPassConfig *SystemZTargetMachine::createPassConfig(PassManagerBase &PM) {
return new SystemZPassConfig(this, PM);
}