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Add workaround for Cortex-M3 errata 602117 by replacing ldrd x, y, [x] with ldm or ldr pairs. 

llvm-svn: 144123
This commit is contained in:
Evan Cheng 2011-11-08 21:21:09 +00:00
parent 0439cfc41f
commit c3770ac687
2 changed files with 21 additions and 14 deletions
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12
llvm/lib/Target/ARM/ARMLoadStoreOptimizer.cpp
View File

@ -62,6 +62,7 @@ namespace {
const TargetInstrInfo *TII;
const TargetRegisterInfo *TRI;
const ARMSubtarget *STI;
ARMFunctionInfo *AFI;
RegScavenger *RS;
bool isThumb2;
@ -1071,11 +1072,17 @@ bool ARMLoadStoreOpt::FixInvalidRegPairOp(MachineBasicBlock &MBB,
unsigned Opcode = MI->getOpcode();
if (Opcode == ARM::LDRD || Opcode == ARM::STRD ||
Opcode == ARM::t2LDRDi8 || Opcode == ARM::t2STRDi8) {
const MachineOperand &BaseOp = MI->getOperand(2);
unsigned BaseReg = BaseOp.getReg();
unsigned EvenReg = MI->getOperand(0).getReg();
unsigned OddReg = MI->getOperand(1).getReg();
unsigned EvenRegNum = TRI->getDwarfRegNum(EvenReg, false);
unsigned OddRegNum = TRI->getDwarfRegNum(OddReg, false);
if ((EvenRegNum & 1) == 0 && (EvenRegNum + 1) == OddRegNum)
// ARM errata 602117: LDRD with base in list may result in incorrect base
// register when interrupted or faulted.
bool Errata602117 = EvenReg == BaseReg && STI->getCPUString() == "cortex-m3";
if (!Errata602117 &&
((EvenRegNum & 1) == 0 && (EvenRegNum + 1) == OddRegNum))
return false;
MachineBasicBlock::iterator NewBBI = MBBI;
@ -1087,8 +1094,6 @@ bool ARMLoadStoreOpt::FixInvalidRegPairOp(MachineBasicBlock &MBB,
bool OddDeadKill = isLd ?
MI->getOperand(1).isDead() : MI->getOperand(1).isKill();
bool OddUndef = MI->getOperand(1).isUndef();
const MachineOperand &BaseOp = MI->getOperand(2);
unsigned BaseReg = BaseOp.getReg();
bool BaseKill = BaseOp.isKill();
bool BaseUndef = BaseOp.isUndef();
bool OffKill = isT2 ? false : MI->getOperand(3).isKill();
@ -1380,6 +1385,7 @@ bool ARMLoadStoreOpt::runOnMachineFunction(MachineFunction &Fn) {
AFI = Fn.getInfo<ARMFunctionInfo>();
TII = TM.getInstrInfo();
TRI = TM.getRegisterInfo();
STI = &TM.getSubtarget<ARMSubtarget>();
RS = new RegScavenger();
isThumb2 = AFI->isThumb2Function();

23
llvm/test/CodeGen/ARM/ldrd.ll
View File

@ -1,21 +1,22 @@
; RUN: llc < %s -mtriple=armv6-apple-darwin -regalloc=linearscan | FileCheck %s -check-prefix=V6
; RUN: llc < %s -mtriple=armv5-apple-darwin -regalloc=linearscan | FileCheck %s -check-prefix=V5
; RUN: llc < %s -mtriple=armv6-eabi -regalloc=linearscan | FileCheck %s -check-prefix=EABI
; rdar://r6949835
; RUN: llc < %s -mtriple=thumbv7-apple-ios -mcpu=cortex-a8 -regalloc=fast | FileCheck %s -check-prefix=A8
; RUN: llc < %s -mtriple=thumbv7-apple-ios -mcpu=cortex-m3 -regalloc=fast | FileCheck %s -check-prefix=M3
; rdar://6949835
; Magic ARM pair hints works best with linearscan.
; Magic ARM pair hints works best with linearscan / fast.
; Cortex-M3 errata 602117: LDRD with base in list may result in incorrect base
; register when interrupted or faulted.
@b = external global i64*
define i64 @t(i64 %a) nounwind readonly {
entry:
;V6: ldrd r2, r3, [r2]
; A8: t:
; A8: ldrd r2, r3, [r2]
;V5: ldr r{{[0-9]+}}, [r2]
;V5: ldr r{{[0-9]+}}, [r2, #4]
;EABI: ldr r{{[0-9]+}}, [r2]
;EABI: ldr r{{[0-9]+}}, [r2, #4]
; M3: t:
; M3-NOT: ldrd
; M3: ldm.w r2, {r2, r3}
%0 = load i64** @b, align 4
%1 = load i64* %0, align 4