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XCore target: Fix eliminateFrameIndex() to handle large frames

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Large frame offsets are loaded from the ConstantPool.
Where possible, offsets are encoded using the smaller MKMSK instruction.
Large frame offsets can only be used when there is a frame-pointer.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@196085 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Robert Lytton 2013-12-02 10:18:19 +00:00
parent 1326c6f14b
commit 25464b948f
2 changed files with 60 additions and 7 deletions
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25
lib/Target/XCore/XCoreRegisterInfo.cpp
View File

@ -16,16 +16,19 @@
#include "XCoreMachineFunctionInfo.h"
#include "llvm/ADT/BitVector.h"
#include "llvm/ADT/STLExtras.h"
#include "llvm/CodeGen/MachineConstantPool.h"
#include "llvm/CodeGen/MachineFrameInfo.h"
#include "llvm/CodeGen/MachineFunction.h"
#include "llvm/CodeGen/MachineInstrBuilder.h"
#include "llvm/CodeGen/MachineModuleInfo.h"
#include "llvm/CodeGen/MachineRegisterInfo.h"
#include "llvm/CodeGen/RegisterScavenging.h"
#include "llvm/IR/Constants.h"
#include "llvm/IR/Function.h"
#include "llvm/IR/Type.h"
#include "llvm/Support/Debug.h"
#include "llvm/Support/ErrorHandling.h"
#include "llvm/Support/MathExtras.h"
#include "llvm/Support/raw_ostream.h"
#include "llvm/Target/TargetFrameLowering.h"
#include "llvm/Target/TargetInstrInfo.h"
@ -244,14 +247,22 @@ XCoreRegisterInfo::eliminateFrameIndex(MachineBasicBlock::iterator II,
void XCoreRegisterInfo::
loadConstant(MachineBasicBlock &MBB, MachineBasicBlock::iterator I,
unsigned DstReg, int64_t Value, DebugLoc dl) const {
// TODO use mkmsk if possible.
if (!isImmU16(Value)) {
// TODO use constant pool.
report_fatal_error("loadConstant value too big " + Twine(Value));
}
int Opcode = isImmU6(Value) ? XCore::LDC_ru6 : XCore::LDC_lru6;
const TargetInstrInfo &TII = *MBB.getParent()->getTarget().getInstrInfo();
BuildMI(MBB, I, dl, TII.get(Opcode), DstReg).addImm(Value);
if (isMask_32(Value)) {
int N = Log2_32(Value) + 1;
BuildMI(MBB, I, dl, TII.get(XCore::MKMSK_rus), DstReg).addImm(N);
} else if (isImmU16(Value)) {
int Opcode = isImmU6(Value) ? XCore::LDC_ru6 : XCore::LDC_lru6;
BuildMI(MBB, I, dl, TII.get(Opcode), DstReg).addImm(Value);
return;
} else {
MachineConstantPool *ConstantPool = MBB.getParent()->getConstantPool();
const Constant *C = ConstantInt::get(
Type::getInt32Ty(MBB.getParent()->getFunction()->getContext()), Value);
unsigned Idx = ConstantPool->getConstantPoolIndex(C, 4);
BuildMI(MBB, I, dl, TII.get(XCore::LDWCP_lru6), DstReg)
.addConstantPoolIndex(Idx);
}
}
unsigned XCoreRegisterInfo::getFrameRegister(const MachineFunction &MF) const {

42
test/CodeGen/XCore/epilogue_prologue_fp.ll Normal file
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@ -0,0 +1,42 @@
; Functions with frames > 256K bytes require a frame pointer to access the stack.
; At present, functions must be compiled using '-fno-omit-frame-pointer'.
; RUN: llc < %s -march=xcore -disable-fp-elim | FileCheck %s
declare void @f0(i32*)
; CHECK: .section .cp.rodata.cst4,"aMc",@progbits,4
; CHECK: .LCPI[[NUM:[0-9_]+]]:
; CHECK: .long 99999
; CHECK: .text
; CHECK-LABEL:f1
; CHECK: entsp 65535
; CHECK-NEXT: extsp 34465
; CHECK-NEXT: stw r10, sp[1]
; CHECK-NEXT: ldaw r10, sp[0]
; CHECK-NEXT: ldw r1, cp[.LCPI[[NUM]]]
; CHECK-NEXT: ldaw r0, r10[r1]
; CHECK-NEXT: extsp 1
; CHECK-NEXT: bl f0
; CHECK-NEXT: ldaw sp, sp[1]
; CHECK-NEXT: set sp, r10
; CHECK-NEXT: ldw r10, sp[1]
; CHECK-NEXT: ldaw sp, sp[65535]
; CHECK-NEXT: retsp 34465
define void @f1() nounwind {
entry:
%0 = alloca [99998 x i32]
%1 = getelementptr inbounds [99998 x i32]* %0, i32 0, i32 99997
call void @f0(i32* %1)
ret void
}
; CHECK-LABEL:f2
; CHECK: mkmsk [[REG:r[0-9]+]], 15
; CHECK-NEXT: ldaw r0, r10{{\[}}[[REG]]{{\]}}
define void @f2() nounwind {
entry:
%0 = alloca [32768 x i32]
%1 = getelementptr inbounds [32768 x i32]* %0, i32 0, i32 32765
call void @f0(i32* %1)
ret void
}