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44b486ed78
Before this change, the SystemZ backend would use BRCL for all branches
and only consider shortening them to BRC when generating an object file.
E.g. a branch on equal would use the JGE alias of BRCL in assembly output,
but might be shortened to the JE alias of BRC in ELF output. This was
a useful first step, but it had two problems:
(1) The z assembler isn't traditionally supposed to perform branch shortening
or branch relaxation. We followed this rule by not relaxing branches
in assembler input, but that meant that generating assembly code and
then assembling it would not produce the same result as going directly
to object code; the former would give long branches everywhere, whereas
the latter would use short branches where possible.
(2) Other useful branches, like COMPARE AND BRANCH, do not have long forms.
We would need to do something else before supporting them.
(Although COMPARE AND BRANCH does not change the condition codes,
the plan is to model COMPARE AND BRANCH as a CC-clobbering instruction
during codegen, so that we can safely lower it to a separate compare
and long branch where necessary. This is not a valid transformation
for the assembler proper to make.)
This patch therefore moves branch relaxation to a pre-emit pass.
For now, calls are still shortened from BRASL to BRAS by the assembler,
although this too is not really the traditional behaviour.
The first test takes about 1.5s to run, and there are likely to be
more tests in this vein once further branch types are added. The feeling
on IRC was that 1.5s is a bit much for a single test, so I've restricted
it to SystemZ hosts for now.
The patch exposes (and fixes) some typos in the main CodeGen/SystemZ tests.
A later patch will remove the {{g}}s from that directory.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@182274 91177308-0d34-0410-b5e6-96231b3b80d8
127 lines
5.0 KiB
C++
127 lines
5.0 KiB
C++
//===-- SystemZInstrInfo.h - SystemZ instruction information ----*- C++ -*-===//
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//
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// The LLVM Compiler Infrastructure
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//
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// This file is distributed under the University of Illinois Open Source
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// License. See LICENSE.TXT for details.
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//
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//===----------------------------------------------------------------------===//
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//
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// This file contains the SystemZ implementation of the TargetInstrInfo class.
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//
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//===----------------------------------------------------------------------===//
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#ifndef LLVM_TARGET_SYSTEMZINSTRINFO_H
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#define LLVM_TARGET_SYSTEMZINSTRINFO_H
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#include "SystemZ.h"
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#include "SystemZRegisterInfo.h"
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#include "llvm/Target/TargetInstrInfo.h"
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#define GET_INSTRINFO_HEADER
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#include "SystemZGenInstrInfo.inc"
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namespace llvm {
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class SystemZTargetMachine;
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namespace SystemZII {
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enum {
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// See comments in SystemZInstrFormats.td.
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SimpleBDXLoad = (1 << 0),
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SimpleBDXStore = (1 << 1),
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Has20BitOffset = (1 << 2),
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HasIndex = (1 << 3),
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Is128Bit = (1 << 4)
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};
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// SystemZ MachineOperand target flags.
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enum {
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// Masks out the bits for the access model.
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MO_SYMBOL_MODIFIER = (1 << 0),
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// @GOT (aka @GOTENT)
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MO_GOT = (1 << 0)
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};
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}
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class SystemZInstrInfo : public SystemZGenInstrInfo {
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const SystemZRegisterInfo RI;
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void splitMove(MachineBasicBlock::iterator MI, unsigned NewOpcode) const;
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void splitAdjDynAlloc(MachineBasicBlock::iterator MI) const;
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public:
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explicit SystemZInstrInfo(SystemZTargetMachine &TM);
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// Override TargetInstrInfo.
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virtual unsigned isLoadFromStackSlot(const MachineInstr *MI,
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int &FrameIndex) const LLVM_OVERRIDE;
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virtual unsigned isStoreToStackSlot(const MachineInstr *MI,
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int &FrameIndex) const LLVM_OVERRIDE;
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virtual bool AnalyzeBranch(MachineBasicBlock &MBB,
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MachineBasicBlock *&TBB,
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MachineBasicBlock *&FBB,
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SmallVectorImpl<MachineOperand> &Cond,
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bool AllowModify) const LLVM_OVERRIDE;
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virtual unsigned RemoveBranch(MachineBasicBlock &MBB) const LLVM_OVERRIDE;
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virtual unsigned InsertBranch(MachineBasicBlock &MBB, MachineBasicBlock *TBB,
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MachineBasicBlock *FBB,
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const SmallVectorImpl<MachineOperand> &Cond,
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DebugLoc DL) const LLVM_OVERRIDE;
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virtual void copyPhysReg(MachineBasicBlock &MBB,
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MachineBasicBlock::iterator MBBI, DebugLoc DL,
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unsigned DestReg, unsigned SrcReg,
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bool KillSrc) const LLVM_OVERRIDE;
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virtual void
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storeRegToStackSlot(MachineBasicBlock &MBB,
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MachineBasicBlock::iterator MBBI,
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unsigned SrcReg, bool isKill, int FrameIndex,
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const TargetRegisterClass *RC,
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const TargetRegisterInfo *TRI) const LLVM_OVERRIDE;
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virtual void
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loadRegFromStackSlot(MachineBasicBlock &MBB,
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MachineBasicBlock::iterator MBBI,
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unsigned DestReg, int FrameIdx,
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const TargetRegisterClass *RC,
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const TargetRegisterInfo *TRI) const LLVM_OVERRIDE;
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virtual bool
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expandPostRAPseudo(MachineBasicBlock::iterator MBBI) const LLVM_OVERRIDE;
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virtual bool
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ReverseBranchCondition(SmallVectorImpl<MachineOperand> &Cond) const
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LLVM_OVERRIDE;
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// Return the SystemZRegisterInfo, which this class owns.
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const SystemZRegisterInfo &getRegisterInfo() const { return RI; }
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// Return the size in bytes of MI.
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uint64_t getInstSizeInBytes(const MachineInstr *MI) const;
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// Return true if MI is a conditional or unconditional branch.
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// When returning true, set Cond to the mask of condition-code
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// values on which the instruction will branch, and set Target
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// to the operand that contains the branch target. This target
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// can be a register or a basic block.
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bool isBranch(const MachineInstr *MI, unsigned &Cond,
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const MachineOperand *&Target) const;
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// Get the load and store opcodes for a given register class.
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void getLoadStoreOpcodes(const TargetRegisterClass *RC,
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unsigned &LoadOpcode, unsigned &StoreOpcode) const;
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// Opcode is the opcode of an instruction that has an address operand,
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// and the caller wants to perform that instruction's operation on an
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// address that has displacement Offset. Return the opcode of a suitable
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// instruction (which might be Opcode itself) or 0 if no such instruction
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// exists.
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unsigned getOpcodeForOffset(unsigned Opcode, int64_t Offset) const;
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// Emit code before MBBI in MI to move immediate value Value into
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// physical register Reg.
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void loadImmediate(MachineBasicBlock &MBB,
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MachineBasicBlock::iterator MBBI,
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unsigned Reg, uint64_t Value) const;
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};
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} // end namespace llvm
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#endif
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