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llvm-mirror/lib/Target/X86/X86MacroFusion.cpp
Amaury Sechet 33cce86cf0 [X86] Avoid using high register trick for test instruction
Summary:
It seems it's main effect is to create addition copies when values are inr register that do not support this trick, which increase register pressure and makes the code bigger.

Reviewers: craig.topper, niravd, spatel, hfinkel

Subscribers: llvm-commits

Differential Revision: https://reviews.llvm.org/D42646

llvm-svn: 323888
2018-01-31 16:48:54 +00:00

200 lines
4.7 KiB
C++

//===- X86MacroFusion.cpp - X86 Macro Fusion ------------------------------===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
/// \file This file contains the X86 implementation of the DAG scheduling
/// mutation to pair instructions back to back.
//
//===----------------------------------------------------------------------===//
#include "X86MacroFusion.h"
#include "X86Subtarget.h"
#include "llvm/CodeGen/MacroFusion.h"
#include "llvm/CodeGen/TargetInstrInfo.h"
using namespace llvm;
/// \brief Check if the instr pair, FirstMI and SecondMI, should be fused
/// together. Given SecondMI, when FirstMI is unspecified, then check if
/// SecondMI may be part of a fused pair at all.
static bool shouldScheduleAdjacent(const TargetInstrInfo &TII,
const TargetSubtargetInfo &TSI,
const MachineInstr *FirstMI,
const MachineInstr &SecondMI) {
const X86Subtarget &ST = static_cast<const X86Subtarget&>(TSI);
// Check if this processor supports macro-fusion.
if (!ST.hasMacroFusion())
return false;
enum {
FuseTest,
FuseCmp,
FuseInc
} FuseKind;
unsigned FirstOpcode = FirstMI
? FirstMI->getOpcode()
: static_cast<unsigned>(X86::INSTRUCTION_LIST_END);
unsigned SecondOpcode = SecondMI.getOpcode();
switch (SecondOpcode) {
default:
return false;
case X86::JE_1:
case X86::JNE_1:
case X86::JL_1:
case X86::JLE_1:
case X86::JG_1:
case X86::JGE_1:
FuseKind = FuseInc;
break;
case X86::JB_1:
case X86::JBE_1:
case X86::JA_1:
case X86::JAE_1:
FuseKind = FuseCmp;
break;
case X86::JS_1:
case X86::JNS_1:
case X86::JP_1:
case X86::JNP_1:
case X86::JO_1:
case X86::JNO_1:
FuseKind = FuseTest;
break;
}
switch (FirstOpcode) {
default:
return false;
case X86::TEST8rr:
case X86::TEST16rr:
case X86::TEST32rr:
case X86::TEST64rr:
case X86::TEST8ri:
case X86::TEST16ri:
case X86::TEST32ri:
case X86::TEST32i32:
case X86::TEST64i32:
case X86::TEST64ri32:
case X86::TEST8mr:
case X86::TEST16mr:
case X86::TEST32mr:
case X86::TEST64mr:
case X86::AND16i16:
case X86::AND16ri:
case X86::AND16ri8:
case X86::AND16rm:
case X86::AND16rr:
case X86::AND32i32:
case X86::AND32ri:
case X86::AND32ri8:
case X86::AND32rm:
case X86::AND32rr:
case X86::AND64i32:
case X86::AND64ri32:
case X86::AND64ri8:
case X86::AND64rm:
case X86::AND64rr:
case X86::AND8i8:
case X86::AND8ri:
case X86::AND8rm:
case X86::AND8rr:
return true;
case X86::CMP16i16:
case X86::CMP16ri:
case X86::CMP16ri8:
case X86::CMP16rm:
case X86::CMP16rr:
case X86::CMP32i32:
case X86::CMP32ri:
case X86::CMP32ri8:
case X86::CMP32rm:
case X86::CMP32rr:
case X86::CMP64i32:
case X86::CMP64ri32:
case X86::CMP64ri8:
case X86::CMP64rm:
case X86::CMP64rr:
case X86::CMP8i8:
case X86::CMP8ri:
case X86::CMP8rm:
case X86::CMP8rr:
case X86::ADD16i16:
case X86::ADD16ri:
case X86::ADD16ri8:
case X86::ADD16ri8_DB:
case X86::ADD16ri_DB:
case X86::ADD16rm:
case X86::ADD16rr:
case X86::ADD16rr_DB:
case X86::ADD32i32:
case X86::ADD32ri:
case X86::ADD32ri8:
case X86::ADD32ri8_DB:
case X86::ADD32ri_DB:
case X86::ADD32rm:
case X86::ADD32rr:
case X86::ADD32rr_DB:
case X86::ADD64i32:
case X86::ADD64ri32:
case X86::ADD64ri32_DB:
case X86::ADD64ri8:
case X86::ADD64ri8_DB:
case X86::ADD64rm:
case X86::ADD64rr:
case X86::ADD64rr_DB:
case X86::ADD8i8:
case X86::ADD8mi:
case X86::ADD8mr:
case X86::ADD8ri:
case X86::ADD8rm:
case X86::ADD8rr:
case X86::SUB16i16:
case X86::SUB16ri:
case X86::SUB16ri8:
case X86::SUB16rm:
case X86::SUB16rr:
case X86::SUB32i32:
case X86::SUB32ri:
case X86::SUB32ri8:
case X86::SUB32rm:
case X86::SUB32rr:
case X86::SUB64i32:
case X86::SUB64ri32:
case X86::SUB64ri8:
case X86::SUB64rm:
case X86::SUB64rr:
case X86::SUB8i8:
case X86::SUB8ri:
case X86::SUB8rm:
case X86::SUB8rr:
return FuseKind == FuseCmp || FuseKind == FuseInc;
case X86::INC16r:
case X86::INC32r:
case X86::INC64r:
case X86::INC8r:
case X86::DEC16r:
case X86::DEC32r:
case X86::DEC64r:
case X86::DEC8r:
return FuseKind == FuseInc;
case X86::INSTRUCTION_LIST_END:
return true;
}
}
namespace llvm {
std::unique_ptr<ScheduleDAGMutation>
createX86MacroFusionDAGMutation () {
return createBranchMacroFusionDAGMutation(shouldScheduleAdjacent);
}
} // end namespace llvm