1 //===-- SystemZTargetMachine.cpp - Define TargetMachine for SystemZ -------===//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 #include "SystemZTargetMachine.h"
11 #include "llvm/CodeGen/Passes.h"
12 #include "llvm/Support/TargetRegistry.h"
16 extern "C" void LLVMInitializeSystemZTarget() {
17 // Register the target.
18 RegisterTargetMachine<SystemZTargetMachine> X(TheSystemZTarget);
21 SystemZTargetMachine::SystemZTargetMachine(const Target &T, StringRef TT,
22 StringRef CPU, StringRef FS,
23 const TargetOptions &Options,
27 : LLVMTargetMachine(T, TT, CPU, FS, Options, RM, CM, OL),
28 Subtarget(TT, CPU, FS),
29 // Make sure that global data has at least 16 bits of alignment by default,
30 // so that we can refer to it using LARL. We don't have any special
31 // requirements for stack variables though.
32 DL("E-p:64:64:64-i1:8:16-i8:8:16-i16:16-i32:32-i64:64"
33 "-f32:32-f64:64-f128:64-a0:8:16-n32:64"),
34 InstrInfo(*this), TLInfo(*this), TSInfo(*this),
35 FrameLowering(*this, Subtarget) {
40 /// SystemZ Code Generator Pass Configuration Options.
41 class SystemZPassConfig : public TargetPassConfig {
43 SystemZPassConfig(SystemZTargetMachine *TM, PassManagerBase &PM)
44 : TargetPassConfig(TM, PM) {}
46 SystemZTargetMachine &getSystemZTargetMachine() const {
47 return getTM<SystemZTargetMachine>();
50 virtual bool addInstSelector() LLVM_OVERRIDE;
51 virtual bool addPreSched2() LLVM_OVERRIDE;
52 virtual bool addPreEmitPass() LLVM_OVERRIDE;
54 } // end anonymous namespace
56 bool SystemZPassConfig::addInstSelector() {
57 addPass(createSystemZISelDag(getSystemZTargetMachine(), getOptLevel()));
61 bool SystemZPassConfig::addPreSched2() {
62 if (getSystemZTargetMachine().getSubtargetImpl()->hasLoadStoreOnCond())
63 addPass(&IfConverterID);
67 bool SystemZPassConfig::addPreEmitPass() {
68 // We eliminate comparisons here rather than earlier because some
69 // transformations can change the set of available CC values and we
70 // generally want those transformations to have priority. This is
71 // especially true in the commonest case where the result of the comparison
72 // is used by a single in-range branch instruction, since we will then
73 // be able to fuse the compare and the branch instead.
75 // For example, two-address NILF can sometimes be converted into
76 // three-address RISBLG. NILF produces a CC value that indicates whether
77 // the low word is zero, but RISBLG does not modify CC at all. On the
78 // other hand, 64-bit ANDs like NILL can sometimes be converted to RISBG.
79 // The CC value produced by NILL isn't useful for our purposes, but the
80 // value produced by RISBG can be used for any comparison with zero
81 // (not just equality). So there are some transformations that lose
82 // CC values (while still being worthwhile) and others that happen to make
83 // the CC result more useful than it was originally.
85 // Doing it so late makes it more likely that a register will be reused
86 // between the comparison and the branch, but it isn't clear whether
87 // preventing that would be a win or not.
88 if (getOptLevel() != CodeGenOpt::None)
89 addPass(createSystemZElimComparePass(getSystemZTargetMachine()));
90 addPass(createSystemZLongBranchPass(getSystemZTargetMachine()));
94 TargetPassConfig *SystemZTargetMachine::createPassConfig(PassManagerBase &PM) {
95 return new SystemZPassConfig(this, PM);