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[ARM] Make the frame lowering code ready for shrink-wrapping. 

Shrink-wrapping can now be tested on ARM with -enable-shrink-wrap.

Related to <rdar://problem/20821730>

llvm-svn: 242908
This commit is contained in:
Quentin Colombet 2015-07-22 16:34:37 +00:00
parent 5b0688edfd
commit 48b772007f
5 changed files with 1230 additions and 123 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
llvm/lib/Target/ARM/ARMFrameLowering.cpp
View File

@ -288,7 +288,6 @@ static void emitAligningInstructions(MachineFunction &MF, ARMFunctionInfo *AFI,
void ARMFrameLowering::emitPrologue(MachineFunction &MF,
MachineBasicBlock &MBB) const {
assert(&MBB == &MF.front() && "Shrink-wrapping not yet implemented");
MachineBasicBlock::iterator MBBI = MBB.begin();
MachineFrameInfo *MFI = MF.getFrameInfo();
ARMFunctionInfo *AFI = MF.getInfo<ARMFunctionInfo>();
@ -1842,7 +1841,6 @@ void ARMFrameLowering::adjustForSegmentedStacks(
if (!ST->isTargetAndroid() && !ST->isTargetLinux())
report_fatal_error("Segmented stacks not supported on this platform.");
assert(&PrologueMBB == &MF.front() && "Shrink-wrapping not yet implemented");
MachineFrameInfo *MFI = MF.getFrameInfo();
MachineModuleInfo &MMI = MF.getMMI();
MCContext &Context = MMI.getContext();

262
llvm/lib/Target/ARM/Thumb1FrameLowering.cpp
View File

@ -85,7 +85,6 @@ eliminateCallFramePseudoInstr(MachineFunction &MF, MachineBasicBlock &MBB,
void Thumb1FrameLowering::emitPrologue(MachineFunction &MF,
MachineBasicBlock &MBB) const {
assert(&MBB == &MF.front() && "Shrink-wrapping not yet implemented");
MachineBasicBlock::iterator MBBI = MBB.begin();
MachineFrameInfo *MFI = MF.getFrameInfo();
ARMFunctionInfo *AFI = MF.getInfo<ARMFunctionInfo>();
@ -385,135 +384,156 @@ void Thumb1FrameLowering::emitEpilogue(MachineFunction &MF,
}
}
if (needPopSpecialFixUp(MF)) {
bool Done = emitPopSpecialFixUp(MBB, /* DoIt */ true);
(void)Done;
assert(Done && "Emission of the special fixup failed!?");
}
}
bool Thumb1FrameLowering::canUseAsEpilogue(const MachineBasicBlock &MBB) const {
if (!needPopSpecialFixUp(*MBB.getParent()))
return true;
MachineBasicBlock *TmpMBB = const_cast<MachineBasicBlock *>(&MBB);
return emitPopSpecialFixUp(*TmpMBB, /* DoIt */ false);
}
bool Thumb1FrameLowering::needPopSpecialFixUp(const MachineFunction &MF) const {
ARMFunctionInfo *AFI =
const_cast<MachineFunction *>(&MF)->getInfo<ARMFunctionInfo>();
if (AFI->getArgRegsSaveSize())
return true;
bool IsV4PopReturn = false;
for (const CalleeSavedInfo &CSI : MFI->getCalleeSavedInfo())
for (const CalleeSavedInfo &CSI : MF.getFrameInfo()->getCalleeSavedInfo())
if (CSI.getReg() == ARM::LR)
IsV4PopReturn = true;
IsV4PopReturn &= STI.hasV4TOps() && !STI.hasV5TOps();
return IsV4PopReturn && STI.hasV4TOps() && !STI.hasV5TOps();
}
// Unlike T2 and ARM mode, the T1 pop instruction cannot restore
// to LR, and we can't pop the value directly to the PC since
// we need to update the SP after popping the value. So instead
// we have to emit:
// POP {r3}
// ADD sp, #offset
// BX r3
// If this would clobber a return value, then generate this sequence instead:
// MOV ip, r3
// POP {r3}
// ADD sp, #offset
// MOV lr, r3
// MOV r3, ip
// BX lr
if (ArgRegsSaveSize || IsV4PopReturn) {
// If MBBI is a return instruction, we may be able to directly restore
// LR in the PC.
// This is possible if we do not need to emit any SP update.
// Otherwise, we need a temporary register to pop the value
// and copy that value into LR.
MBBI = MBB.getFirstTerminator();
if (!ArgRegsSaveSize && MBBI != MBB.end() &&
MBBI->getOpcode() == ARM::tBX_RET) {
MachineInstrBuilder MIB =
AddDefaultPred(
BuildMI(MBB, MBBI, MBBI->getDebugLoc(), TII.get(ARM::tPOP_RET)))
.addReg(ARM::PC, RegState::Define);
MIB.copyImplicitOps(&*MBBI);
// erase the old tBX_RET instruction
MBB.erase(MBBI);
return;
}
bool Thumb1FrameLowering::emitPopSpecialFixUp(MachineBasicBlock &MBB,
bool DoIt) const {
MachineFunction &MF = *MBB.getParent();
ARMFunctionInfo *AFI = MF.getInfo<ARMFunctionInfo>();
unsigned ArgRegsSaveSize = AFI->getArgRegsSaveSize();
const TargetInstrInfo &TII = *STI.getInstrInfo();
const ThumbRegisterInfo *RegInfo =
static_cast<const ThumbRegisterInfo *>(STI.getRegisterInfo());
// Look for a temporary register to use.
// First, compute the liveness information.
LivePhysRegs UsedRegs(STI.getRegisterInfo());
UsedRegs.addLiveOuts(&MBB, /*AddPristines*/ true);
// The semantic of pristines changed recently and now,
// the callee-saved registers that are touched in the function
// are not part of the pristines set anymore.
// Add those callee-saved now.
const TargetRegisterInfo *TRI = STI.getRegisterInfo();
const MCPhysReg *CSRegs = TRI->getCalleeSavedRegs(&MF);
for (unsigned i = 0; CSRegs[i]; ++i)
UsedRegs.addReg(CSRegs[i]);
// If MBBI is a return instruction, we may be able to directly restore
// LR in the PC.
// This is possible if we do not need to emit any SP update.
// Otherwise, we need a temporary register to pop the value
// and copy that value into LR.
auto MBBI = MBB.getFirstTerminator();
if (!ArgRegsSaveSize && MBBI != MBB.end() &&
MBBI->getOpcode() == ARM::tBX_RET) {
if (!DoIt)
return true;
MachineInstrBuilder MIB =
AddDefaultPred(
BuildMI(MBB, MBBI, MBBI->getDebugLoc(), TII.get(ARM::tPOP_RET)))
.addReg(ARM::PC, RegState::Define);
MIB.copyImplicitOps(&*MBBI);
// erase the old tBX_RET instruction
MBB.erase(MBBI);
return true;
}
DebugLoc dl = DebugLoc();
if (MBBI != MBB.end()) {
dl = MBBI->getDebugLoc();
auto InstUpToMBBI = MBB.end();
// The post-decrement is on purpose here.
// We want to have the liveness right before MBBI.
while (InstUpToMBBI-- != MBBI)
UsedRegs.stepBackward(*InstUpToMBBI);
}
// Look for a temporary register to use.
// First, compute the liveness information.
LivePhysRegs UsedRegs(STI.getRegisterInfo());
UsedRegs.addLiveOuts(&MBB, /*AddPristines*/ true);
// The semantic of pristines changed recently and now,
// the callee-saved registers that are touched in the function
// are not part of the pristines set anymore.
// Add those callee-saved now.
const TargetRegisterInfo *TRI = STI.getRegisterInfo();
const MCPhysReg *CSRegs = TRI->getCalleeSavedRegs(&MF);
for (unsigned i = 0; CSRegs[i]; ++i)
UsedRegs.addReg(CSRegs[i]);
// Look for a register that can be directly use in the POP.
unsigned PopReg = 0;
// And some temporary register, just in case.
unsigned TemporaryReg = 0;
BitVector PopFriendly =
TRI->getAllocatableSet(MF, TRI->getRegClass(ARM::tGPRRegClassID));
assert(PopFriendly.any() && "No allocatable pop-friendly register?!");
// Rebuild the GPRs from the high registers because they are removed
// form the GPR reg class for thumb1.
BitVector GPRsNoLRSP =
TRI->getAllocatableSet(MF, TRI->getRegClass(ARM::hGPRRegClassID));
GPRsNoLRSP |= PopFriendly;
GPRsNoLRSP.reset(ARM::LR);
GPRsNoLRSP.reset(ARM::SP);
GPRsNoLRSP.reset(ARM::PC);
for (int Register = GPRsNoLRSP.find_first(); Register != -1;
Register = GPRsNoLRSP.find_next(Register)) {
if (!UsedRegs.contains(Register)) {
// Remember the first pop-friendly register and exit.
if (PopFriendly.test(Register)) {
PopReg = Register;
TemporaryReg = 0;
break;
}
// Otherwise, remember that the register will be available to
// save a pop-friendly register.
TemporaryReg = Register;
DebugLoc dl = DebugLoc();
if (MBBI != MBB.end()) {
dl = MBBI->getDebugLoc();
auto InstUpToMBBI = MBB.end();
// The post-decrement is on purpose here.
// We want to have the liveness right before MBBI.
while (InstUpToMBBI-- != MBBI)
UsedRegs.stepBackward(*InstUpToMBBI);
}
// Look for a register that can be directly use in the POP.
unsigned PopReg = 0;
// And some temporary register, just in case.
unsigned TemporaryReg = 0;
BitVector PopFriendly =
TRI->getAllocatableSet(MF, TRI->getRegClass(ARM::tGPRRegClassID));
assert(PopFriendly.any() && "No allocatable pop-friendly register?!");
// Rebuild the GPRs from the high registers because they are removed
// form the GPR reg class for thumb1.
BitVector GPRsNoLRSP =
TRI->getAllocatableSet(MF, TRI->getRegClass(ARM::hGPRRegClassID));
GPRsNoLRSP |= PopFriendly;
GPRsNoLRSP.reset(ARM::LR);
GPRsNoLRSP.reset(ARM::SP);
GPRsNoLRSP.reset(ARM::PC);
for (int Register = GPRsNoLRSP.find_first(); Register != -1;
Register = GPRsNoLRSP.find_next(Register)) {
if (!UsedRegs.contains(Register)) {
// Remember the first pop-friendly register and exit.
if (PopFriendly.test(Register)) {
PopReg = Register;
TemporaryReg = 0;
break;
}
}
assert((PopReg || TemporaryReg) && "Cannot get LR");
if (TemporaryReg) {
assert(!PopReg && "Unnecessary MOV is about to be inserted");
PopReg = PopFriendly.find_first();
AddDefaultPred(BuildMI(MBB, MBBI, dl, TII.get(ARM::tMOVr))
.addReg(TemporaryReg, RegState::Define)
.addReg(PopReg, RegState::Kill));
}
assert(PopReg && "Do not know how to get LR");
AddDefaultPred(BuildMI(MBB, MBBI, dl, TII.get(ARM::tPOP)))
.addReg(PopReg, RegState::Define);
emitSPUpdate(MBB, MBBI, TII, dl, *RegInfo, ArgRegsSaveSize);
if (!TemporaryReg && MBBI != MBB.end() &&
MBBI->getOpcode() == ARM::tBX_RET) {
MachineInstrBuilder MIB = BuildMI(MBB, MBBI, dl, TII.get(ARM::tBX))
.addReg(PopReg, RegState::Kill);
AddDefaultPred(MIB);
MIB.copyImplicitOps(&*MBBI);
// erase the old tBX_RET instruction
MBB.erase(MBBI);
return;
}
AddDefaultPred(BuildMI(MBB, MBBI, dl, TII.get(ARM::tMOVr))
.addReg(ARM::LR, RegState::Define)
.addReg(PopReg, RegState::Kill));
if (TemporaryReg) {
AddDefaultPred(BuildMI(MBB, MBBI, dl, TII.get(ARM::tMOVr))
.addReg(PopReg, RegState::Define)
.addReg(TemporaryReg, RegState::Kill));
// Otherwise, remember that the register will be available to
// save a pop-friendly register.
TemporaryReg = Register;
}
}
if (!DoIt && !PopReg && !TemporaryReg)
return false;
assert((PopReg || TemporaryReg) && "Cannot get LR");
if (TemporaryReg) {
assert(!PopReg && "Unnecessary MOV is about to be inserted");
PopReg = PopFriendly.find_first();
AddDefaultPred(BuildMI(MBB, MBBI, dl, TII.get(ARM::tMOVr))
.addReg(TemporaryReg, RegState::Define)
.addReg(PopReg, RegState::Kill));
}
assert(PopReg && "Do not know how to get LR");
AddDefaultPred(BuildMI(MBB, MBBI, dl, TII.get(ARM::tPOP)))
.addReg(PopReg, RegState::Define);
emitSPUpdate(MBB, MBBI, TII, dl, *RegInfo, ArgRegsSaveSize);
if (!TemporaryReg && MBBI != MBB.end() && MBBI->getOpcode() == ARM::tBX_RET) {
MachineInstrBuilder MIB = BuildMI(MBB, MBBI, dl, TII.get(ARM::tBX))
.addReg(PopReg, RegState::Kill);
AddDefaultPred(MIB);
MIB.copyImplicitOps(&*MBBI);
// erase the old tBX_RET instruction
MBB.erase(MBBI);
return true;
}
AddDefaultPred(BuildMI(MBB, MBBI, dl, TII.get(ARM::tMOVr))
.addReg(ARM::LR, RegState::Define)
.addReg(PopReg, RegState::Kill));
if (TemporaryReg) {
AddDefaultPred(BuildMI(MBB, MBBI, dl, TII.get(ARM::tMOVr))
.addReg(PopReg, RegState::Define)
.addReg(TemporaryReg, RegState::Kill));
}
return true;
}
bool Thumb1FrameLowering::
@ -567,7 +587,7 @@ restoreCalleeSavedRegisters(MachineBasicBlock &MBB,
const TargetInstrInfo &TII = *STI.getInstrInfo();
bool isVarArg = AFI->getArgRegsSaveSize() > 0;
DebugLoc DL = MI->getDebugLoc();
DebugLoc DL = MI != MBB.end() ? MI->getDebugLoc() : DebugLoc();
MachineInstrBuilder MIB = BuildMI(MF, DL, TII.get(ARM::tPOP));
AddDefaultPred(MIB);

36
llvm/lib/Target/ARM/Thumb1FrameLowering.h
View File

@ -45,6 +45,42 @@ public:
eliminateCallFramePseudoInstr(MachineFunction &MF,
MachineBasicBlock &MBB,
MachineBasicBlock::iterator MI) const override;
/// Check whether or not the given \p MBB can be used as a epilogue
/// for the target.
/// The epilogue will be inserted before the first terminator of that block.
/// This method is used by the shrink-wrapping pass to decide if
/// \p MBB will be correctly handled by the target.
bool canUseAsEpilogue(const MachineBasicBlock &MBB) const override;
private:
/// Check if the frame lowering of \p MF needs a special fixup
/// code sequence for the epilogue.
/// Unlike T2 and ARM mode, the T1 pop instruction cannot restore
/// to LR, and we can't pop the value directly to the PC when
/// we need to update the SP after popping the value. So instead
/// we have to emit:
/// POP {r3}
/// ADD sp, #offset
/// BX r3
/// If this would clobber a return value, then generate this sequence instead:
/// MOV ip, r3
/// POP {r3}
/// ADD sp, #offset
/// MOV lr, r3
/// MOV r3, ip
/// BX lr
bool needPopSpecialFixUp(const MachineFunction &MF) const;
/// Emit the special fixup code sequence for the epilogue.
/// \see needPopSpecialFixUp for more details.
/// \p DoIt, tells this method whether or not to actually insert
/// the code sequence in \p MBB. I.e., when \p DoIt is false,
/// \p MBB is left untouched.
/// \returns For \p DoIt == true: True when the emission succeeded
/// false otherwise. For \p DoIt == false: True when the emission
/// would have been possible, false otherwise.
bool emitPopSpecialFixUp(MachineBasicBlock &MBB, bool DoIt) const;
};
} // End llvm namespace

536
llvm/test/CodeGen/ARM/arm-shrink-wrapping.ll Normal file
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@ -0,0 +1,536 @@
; RUN: llc %s -o - -enable-shrink-wrap=true -ifcvt-fn-start=1 -ifcvt-fn-stop=0 -mtriple=armv7-apple-ios \
; RUN: | FileCheck %s --check-prefix=CHECK --check-prefix=ARM --check-prefix=ENABLE --check-prefix=ARM-ENABLE
; RUN: llc %s -o - -enable-shrink-wrap=false -ifcvt-fn-start=1 -ifcvt-fn-stop=0 -mtriple=armv7-apple-ios \
; RUN: | FileCheck %s --check-prefix=CHECK --check-prefix=ARM --check-prefix=DISABLE --check-prefix=ARM-DISABLE
; RUN: llc %s -o - -enable-shrink-wrap=true -ifcvt-fn-start=1 -ifcvt-fn-stop=0 -mtriple=thumbv7-apple-ios \
; RUN: | FileCheck %s --check-prefix=CHECK --check-prefix=THUMB --check-prefix=ENABLE --check-prefix=THUMB-ENABLE
; RUN: llc %s -o - -enable-shrink-wrap=false -ifcvt-fn-start=1 -ifcvt-fn-stop=0 -mtriple=thumbv7-apple-ios \
; RUN: | FileCheck %s --check-prefix=CHECK --check-prefix=THUMB --check-prefix=DISABLE --check-prefix=THUMB-DISABLE
;
; Note: Lots of tests use inline asm instead of regular calls.
; This allows to have a better control on what the allocation will do.
; Otherwise, we may have spill right in the entry block, defeating
; shrink-wrapping. Moreover, some of the inline asm statements (nop)
; are here to ensure that the related paths do not end up as critical
; edges.
; Also disable the late if-converter as it makes harder to reason on
; the diffs.
; Initial motivating example: Simple diamond with a call just on one side.
; CHECK-LABEL: foo:
;
; Compare the arguments and jump to exit.
; No prologue needed.
; ENABLE: cmp r0, r1
; ENABLE-NEXT: bge [[EXIT_LABEL:LBB[0-9_]+]]
;
; Prologue code.
; CHECK: push {r7, lr}
; CHECK-NEXT: mov r7, sp
;;
; Compare the arguments and jump to exit.
; After the prologue is set.
; DISABLE: sub sp
; DISABLE: cmp r0, r1
; DISABLE-NEXT: bge [[EXIT_LABEL:LBB[0-9_]+]]
;
; Store %a in the alloca.
; ARM-ENABLE: push {r0}
; THUMB-ENABLE: str r0, [sp, #-4]
; DISABLE: str r0, [sp]
; Set the alloca address in the second argument.
; CHECK-NEXT: mov r1, sp
; Set the first argument to zero.
; CHECK-NEXT: mov{{s?}} r0, #0
; CHECK-NEXT: bl{{x?}} _doSomething
;
; With shrink-wrapping, epilogue is just after the call.
; ARM-ENABLE-NEXT: mov sp, r7
; THUMB-ENABLE-NEXT: add sp, #4
; ENABLE-NEXT: pop{{(\.w)?}} {r7, lr}
;
; CHECK: [[EXIT_LABEL]]:
;
; Without shrink-wrapping, epilogue is in the exit block.
; Epilogue code. (What we pop does not matter.)
; ARM-DISABLE: mov sp, r7
; THUMB-DISABLE: add sp,
; DISABLE-NEXT: pop {r7, pc}
;
; ENABLE-NEXT: bx lr
define i32 @foo(i32 %a, i32 %b) {
%tmp = alloca i32, align 4
%tmp2 = icmp slt i32 %a, %b
br i1 %tmp2, label %true, label %false
true:
store i32 %a, i32* %tmp, align 4
%tmp4 = call i32 @doSomething(i32 0, i32* %tmp)
br label %false
false:
%tmp.0 = phi i32 [ %tmp4, %true ], [ %a, %0 ]
ret i32 %tmp.0
}
; Function Attrs: optsize
declare i32 @doSomething(i32, i32*)
; Check that we do not perform the restore inside the loop whereas the save
; is outside.
; CHECK-LABEL: freqSaveAndRestoreOutsideLoop:
;
; Shrink-wrapping allows to skip the prologue in the else case.
; ARM-ENABLE: cmp r0, #0
; ARM-ENABLE-NEXT: beq [[ELSE_LABEL:LBB[0-9_]+]]
; THUMB-ENABLE: cbz r0, [[ELSE_LABEL:LBB[0-9_]+]]
;
; Prologue code.
; Make sure we save the CSR used in the inline asm: r4.
; CHECK: push {r4, r7, lr}
; CHECK-NEXT: add r7, sp, #4
;
; ARM-DISABLE: cmp r0, #0
; ARM-DISABLE-NEXT: beq [[ELSE_LABEL:LBB[0-9_]+]]
; THUMB-DISABLE: cbz r0, [[ELSE_LABEL:LBB[0-9_]+]]
;
; SUM is in r0 because it is coalesced with the second
; argument on the else path.
; CHECK: mov{{s?}} [[SUM:r0]], #0
; CHECK-NEXT: mov{{s?}} [[IV:r[0-9]+]], #10
;
; Next BB.
; CHECK: [[LOOP:LBB[0-9_]+]]: @ %for.body
; CHECK: mov{{(\.w)?}} [[TMP:r[0-9]+]], #1
; ARM: subs [[IV]], [[IV]], #1
; THUMB: subs [[IV]], #1
; ARM-NEXT: add [[SUM]], [[TMP]], [[SUM]]
; THUMB-NEXT: add [[SUM]], [[TMP]]
; CHECK-NEXT: bne [[LOOP]]
;
; Next BB.
; SUM << 3.
; CHECK: lsl{{s?}} [[SUM]], [[SUM]], #3
; ENABLE-NEXT: pop {r4, r7, pc}
;
; Duplicated epilogue.
; DISABLE: pop {r4, r7, pc}
;
; CHECK: [[ELSE_LABEL]]: @ %if.else
; Shift second argument by one and store into returned register.
; CHECK: lsl{{s?}} r0, r1, #1
; DISABLE-NEXT: pop {r4, r7, pc}
;
; ENABLE-NEXT: bx lr
define i32 @freqSaveAndRestoreOutsideLoop(i32 %cond, i32 %N) {
entry:
%tobool = icmp eq i32 %cond, 0
br i1 %tobool, label %if.else, label %for.preheader
for.preheader:
tail call void asm "nop", ""()
br label %for.body
for.body: ; preds = %entry, %for.body
%i.05 = phi i32 [ %inc, %for.body ], [ 0, %for.preheader ]
%sum.04 = phi i32 [ %add, %for.body ], [ 0, %for.preheader ]
%call = tail call i32 asm sideeffect "mov $0, #1", "=r,~{r4}"()
%add = add nsw i32 %call, %sum.04
%inc = add nuw nsw i32 %i.05, 1
%exitcond = icmp eq i32 %inc, 10
br i1 %exitcond, label %for.end, label %for.body
for.end: ; preds = %for.body
%shl = shl i32 %add, 3
br label %if.end
if.else: ; preds = %entry
%mul = shl nsw i32 %N, 1
br label %if.end
if.end: ; preds = %if.else, %for.end
%sum.1 = phi i32 [ %shl, %for.end ], [ %mul, %if.else ]
ret i32 %sum.1
}
declare i32 @something(...)
; Check that we do not perform the shrink-wrapping inside the loop even
; though that would be legal. The cost model must prevent that.
; CHECK-LABEL: freqSaveAndRestoreOutsideLoop2:
; Prologue code.
; Make sure we save the CSR used in the inline asm: r4.
; CHECK: push {r4
; CHECK: mov{{s?}} [[SUM:r0]], #0
; CHECK-NEXT: mov{{s?}} [[IV:r[0-9]+]], #10
; CHECK: nop
; Next BB.
; CHECK: [[LOOP_LABEL:LBB[0-9_]+]]: @ %for.body
; CHECK: mov{{(\.w)?}} [[TMP:r[0-9]+]], #1
; ARM: subs [[IV]], [[IV]], #1
; THUMB: subs [[IV]], #1
; ARM: add [[SUM]], [[TMP]], [[SUM]]
; THUMB: add [[SUM]], [[TMP]]
; CHECK-NEXT: bne [[LOOP_LABEL]]
; Next BB.
; CHECK: @ %for.exit
; CHECK: nop
; CHECK: pop {r4
define i32 @freqSaveAndRestoreOutsideLoop2(i32 %cond) {
entry:
br label %for.preheader
for.preheader:
tail call void asm "nop", ""()
br label %for.body
for.body: ; preds = %for.body, %entry
%i.04 = phi i32 [ 0, %for.preheader ], [ %inc, %for.body ]
%sum.03 = phi i32 [ 0, %for.preheader ], [ %add, %for.body ]
%call = tail call i32 asm sideeffect "mov $0, #1", "=r,~{r4}"()
%add = add nsw i32 %call, %sum.03
%inc = add nuw nsw i32 %i.04, 1
%exitcond = icmp eq i32 %inc, 10
br i1 %exitcond, label %for.exit, label %for.body
for.exit:
tail call void asm "nop", ""()
br label %for.end
for.end: ; preds = %for.body
ret i32 %add
}
; Check with a more complex case that we do not have save within the loop and
; restore outside.
; CHECK-LABEL: loopInfoSaveOutsideLoop:
;
; ARM-ENABLE: cmp r0, #0
; ARM-ENABLE-NEXT: beq [[ELSE_LABEL:LBB[0-9_]+]]
; THUMB-ENABLE: cbz r0, [[ELSE_LABEL:LBB[0-9_]+]]
;
; Prologue code.
; Make sure we save the CSR used in the inline asm: r4.
; CHECK: push {r4, r7, lr}
; CHECK-NEXT: add r7, sp, #4
;
; ARM-DISABLE: cmp r0, #0
; ARM-DISABLE-NEXT: beq [[ELSE_LABEL:LBB[0-9_]+]]
; THUMB-DISABLE: cbz r0, [[ELSE_LABEL:LBB[0-9_]+]]
;
; SUM is in r0 because it is coalesced with the second
; argument on the else path.
; CHECK: mov{{s?}} [[SUM:r0]], #0
; CHECK-NEXT: mov{{s?}} [[IV:r[0-9]+]], #10
;
; Next BB.
; CHECK: [[LOOP:LBB[0-9_]+]]: @ %for.body
; CHECK: mov{{(\.w)?}} [[TMP:r[0-9]+]], #1
; ARM: subs [[IV]], [[IV]], #1
; THUMB: subs [[IV]], #1
; ARM-NEXT: add [[SUM]], [[TMP]], [[SUM]]
; THUMB-NEXT: add [[SUM]], [[TMP]]
; CHECK-NEXT: bne [[LOOP]]
;
; Next BB.
; SUM << 3.
; CHECK: lsl{{s?}} [[SUM]], [[SUM]], #3
; ENABLE: pop {r4, r7, pc}
;
; Duplicated epilogue.
; DISABLE: pop {r4, r7, pc}
;
; CHECK: [[ELSE_LABEL]]: @ %if.else
; Shift second argument by one and store into returned register.
; CHECK: lsl{{s?}} r0, r1, #1
; DISABLE-NEXT: pop {r4, r7, pc}
;
; ENABLE-NEXT: bx lr
define i32 @loopInfoSaveOutsideLoop(i32 %cond, i32 %N) {
entry:
%tobool = icmp eq i32 %cond, 0
br i1 %tobool, label %if.else, label %for.preheader
for.preheader:
tail call void asm "nop", ""()
br label %for.body
for.body: ; preds = %entry, %for.body
%i.05 = phi i32 [ %inc, %for.body ], [ 0, %for.preheader ]
%sum.04 = phi i32 [ %add, %for.body ], [ 0, %for.preheader ]
%call = tail call i32 asm sideeffect "mov $0, #1", "=r,~{r4}"()
%add = add nsw i32 %call, %sum.04
%inc = add nuw nsw i32 %i.05, 1
%exitcond = icmp eq i32 %inc, 10
br i1 %exitcond, label %for.end, label %for.body
for.end: ; preds = %for.body
tail call void asm "nop", "~{r4}"()
%shl = shl i32 %add, 3
br label %if.end
if.else: ; preds = %entry
%mul = shl nsw i32 %N, 1
br label %if.end
if.end: ; preds = %if.else, %for.end
%sum.1 = phi i32 [ %shl, %for.end ], [ %mul, %if.else ]
ret i32 %sum.1
}
declare void @somethingElse(...)
; Check with a more complex case that we do not have restore within the loop and
; save outside.
; CHECK-LABEL: loopInfoRestoreOutsideLoop:
;
; ARM-ENABLE: cmp r0, #0
; ARM-ENABLE-NEXT: beq [[ELSE_LABEL:LBB[0-9_]+]]
; THUMB-ENABLE: cbz r0, [[ELSE_LABEL:LBB[0-9_]+]]
;
; Prologue code.
; Make sure we save the CSR used in the inline asm: r4.
; CHECK: push {r4, r7, lr}
; CHECK-NEXT: add r7, sp, #4
;
; ARM-DISABLE: cmp r0, #0
; ARM-DISABLE-NEXT: beq [[ELSE_LABEL:LBB[0-9_]+]]
; THUMB-DISABLE: cbz r0, [[ELSE_LABEL:LBB[0-9_]+]]
;
; SUM is in r0 because it is coalesced with the second
; argument on the else path.
; CHECK: mov{{s?}} [[SUM:r0]], #0
; CHECK-NEXT: mov{{s?}} [[IV:r[0-9]+]], #10
;
; Next BB.
; CHECK: [[LOOP:LBB[0-9_]+]]: @ %for.body
; CHECK: mov{{(\.w)?}} [[TMP:r[0-9]+]], #1
; ARM: subs [[IV]], [[IV]], #1
; THUMB: subs [[IV]], #1
; ARM-NEXT: add [[SUM]], [[TMP]], [[SUM]]
; THUMB-NEXT: add [[SUM]], [[TMP]]
; CHECK-NEXT: bne [[LOOP]]
;
; Next BB.
; SUM << 3.
; CHECK: lsl{{s?}} [[SUM]], [[SUM]], #3
; ENABLE-NEXT: pop {r4, r7, pc}
;
; Duplicated epilogue.
; DISABLE: pop {r4, r7, pc}
;
; CHECK: [[ELSE_LABEL]]: @ %if.else
; Shift second argument by one and store into returned register.
; CHECK: lsl{{s?}} r0, r1, #1
; DISABLE-NEXT: pop {r4, r7, pc}
;
; ENABLE-NEXT: bx lr
define i32 @loopInfoRestoreOutsideLoop(i32 %cond, i32 %N) #0 {
entry:
%tobool = icmp eq i32 %cond, 0
br i1 %tobool, label %if.else, label %if.then
if.then: ; preds = %entry
tail call void asm "nop", "~{r4}"()
br label %for.body
for.body: ; preds = %for.body, %if.then
%i.05 = phi i32 [ 0, %if.then ], [ %inc, %for.body ]
%sum.04 = phi i32 [ 0, %if.then ], [ %add, %for.body ]
%call = tail call i32 asm sideeffect "mov $0, #1", "=r,~{r4}"()
%add = add nsw i32 %call, %sum.04
%inc = add nuw nsw i32 %i.05, 1
%exitcond = icmp eq i32 %inc, 10
br i1 %exitcond, label %for.end, label %for.body
for.end: ; preds = %for.body
%shl = shl i32 %add, 3
br label %if.end
if.else: ; preds = %entry
%mul = shl nsw i32 %N, 1
br label %if.end
if.end: ; preds = %if.else, %for.end
%sum.1 = phi i32 [ %shl, %for.end ], [ %mul, %if.else ]
ret i32 %sum.1
}
; Check that we handle function with no frame information correctly.
; CHECK-LABEL: emptyFrame:
; CHECK: @ %entry
; CHECK-NEXT: mov{{s?}} r0, #0
; CHECK-NEXT: bx lr
define i32 @emptyFrame() {
entry:
ret i32 0
}
; Check that we handle inline asm correctly.
; CHECK-LABEL: inlineAsm:
;
; ARM-ENABLE: cmp r0, #0
; ARM-ENABLE-NEXT: beq [[ELSE_LABEL:LBB[0-9_]+]]
; THUMB-ENABLE: cbz r0, [[ELSE_LABEL:LBB[0-9_]+]]
;
; Prologue code.
; Make sure we save the CSR used in the inline asm: r4.
; CHECK: push {r4, r7, lr}
; CHECK-NEXT: add r7, sp, #4
;
; ARM-DISABLE: cmp r0, #0
; ARM-DISABLE-NEXT: beq [[ELSE_LABEL:LBB[0-9_]+]]
; THUMB-DISABLE: cbz r0, [[ELSE_LABEL:LBB[0-9_]+]]
;
; CHECK: mov{{s?}} [[IV:r[0-9]+]], #10
;
; Next BB.
; CHECK: [[LOOP:LBB[0-9_]+]]: @ %for.body
; ARM: subs [[IV]], [[IV]], #1
; THUMB: subs [[IV]], #1
; CHECK: add{{(\.w)?}} r4, r4, #1
; CHECK: bne [[LOOP]]
;
; Next BB.
; CHECK: mov{{s?}} r0, #0
;
; Duplicated epilogue.
; DISABLE: pop {r4, r7, pc}
;
; CHECK: [[ELSE_LABEL]]: @ %if.else
; Shift second argument by one and store into returned register.
; CHECK: lsl{{s?}} r0, r1, #1
; DISABLE-NEXT: pop {r4, r7, pc}
;
; ENABLE-NEXT: bx lr
define i32 @inlineAsm(i32 %cond, i32 %N) {
entry:
%tobool = icmp eq i32 %cond, 0
br i1 %tobool, label %if.else, label %for.preheader
for.preheader:
tail call void asm "nop", ""()
br label %for.body
for.body: ; preds = %entry, %for.body
%i.03 = phi i32 [ %inc, %for.body ], [ 0, %for.preheader ]
tail call void asm sideeffect "add r4, #1", "~{r4}"()
%inc = add nuw nsw i32 %i.03, 1
%exitcond = icmp eq i32 %inc, 10
br i1 %exitcond, label %for.exit, label %for.body
for.exit:
tail call void asm "nop", ""()
br label %if.end
if.else: ; preds = %entry
%mul = shl nsw i32 %N, 1
br label %if.end
if.end: ; preds = %for.body, %if.else
%sum.0 = phi i32 [ %mul, %if.else ], [ 0, %for.exit ]
ret i32 %sum.0
}
; Check that we handle calls to variadic functions correctly.
; CHECK-LABEL: callVariadicFunc:
;
; ARM-ENABLE: cmp r0, #0
; ARM-ENABLE-NEXT: beq [[ELSE_LABEL:LBB[0-9_]+]]
; THUMB-ENABLE: cbz r0, [[ELSE_LABEL:LBB[0-9_]+]]
;
; Prologue code.
; CHECK: push {r7, lr}
; CHECK-NEXT: mov r7, sp
; CHECK-NEXT: sub sp, {{(sp, )?}}#12
;
; ARM-DISABLE: cmp r0, #0
; ARM-DISABLE-NEXT: beq [[ELSE_LABEL:LBB[0-9_]+]]
; THUMB-DISABLE-NEXT: cbz r0, [[ELSE_LABEL:LBB[0-9_]+]]
;
; Setup of the varags.
; CHECK: mov r0, r1
; CHECK-NEXT: mov r2, r1
; CHECK-NEXT: mov r3, r1
; ARM-NEXT: str r1, [sp]
; ARM-NEXT: str r1, [sp, #4]
; THUMB-NEXT: strd r1, r1, [sp]
; CHECK-NEXT: str r1, [sp, #8]
; CHECK-NEXT: bl{{x?}} _someVariadicFunc
; CHECK-NEXT: lsl{{s?}} r0, r0, #3
; ARM-NEXT: mov sp, r7
; THUMB-NEXT: add sp, #12
; CHECK-NEXT: pop {r7, pc}
;
; CHECK: [[ELSE_LABEL]]: @ %if.else
; Shift second argument by one and store into returned register.
; CHECK: lsl{{s?}} r0, r1, #1
;
; Epilogue code.
; ENABLE-NEXT: bx lr
;
; ARM-DISABLE-NEXT: mov sp, r7
; THUMB-DISABLE-NEXT: add sp, #12
; DISABLE-NEXT: pop {r7, pc}
define i32 @callVariadicFunc(i32 %cond, i32 %N) {
entry:
%tobool = icmp eq i32 %cond, 0
br i1 %tobool, label %if.else, label %if.then
if.then: ; preds = %entry
%call = tail call i32 (i32, ...) @someVariadicFunc(i32 %N, i32 %N, i32 %N, i32 %N, i32 %N, i32 %N, i32 %N)
%shl = shl i32 %call, 3
br label %if.end
if.else: ; preds = %entry
%mul = shl nsw i32 %N, 1
br label %if.end
if.end: ; preds = %if.else, %if.then
%sum.0 = phi i32 [ %shl, %if.then ], [ %mul, %if.else ]
ret i32 %sum.0
}
declare i32 @someVariadicFunc(i32, ...)
; Make sure we do not insert unreachable code after noreturn function.
; Although this is not incorrect to insert such code, it is useless
; and it hurts the binary size.
;
; CHECK-LABEL: noreturn:
; DISABLE: push
;
; CHECK: tst{{(\.w)?}} r0, #255
; CHECK-NEXT: bne [[ABORT:LBB[0-9_]+]]
;
; CHECK: mov{{s?}} r0, #42
;
; ENABLE-NEXT: bx lr
;
; DISABLE-NEXT: pop
;;
; CHECK: [[ABORT]]: @ %if.abort
;
; ENABLE: push
;
; CHECK: bl{{x?}} _abort
; ENABLE-NOT: pop
define i32 @noreturn(i8 signext %bad_thing) {
entry:
%tobool = icmp eq i8 %bad_thing, 0
br i1 %tobool, label %if.end, label %if.abort
if.abort:
%call = tail call i32 asm sideeffect "mov $0, #1", "=r,~{r4}"()
tail call void @abort() #0
unreachable
if.end:
ret i32 42
}
declare void @abort() #0
attributes #0 = { noreturn nounwind }

517
llvm/test/CodeGen/Thumb/thumb-shrink-wrapping.ll Normal file
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@ -0,0 +1,517 @@
; RUN: llc %s -o - -enable-shrink-wrap=true -ifcvt-fn-start=1 -ifcvt-fn-stop=0 -mtriple=thumb-macho \
; RUN: | FileCheck %s --check-prefix=CHECK --check-prefix=ENABLE
; RUN: llc %s -o - -enable-shrink-wrap=false -ifcvt-fn-start=1 -ifcvt-fn-stop=0 -mtriple=thumb-macho \
; RUN: | FileCheck %s --check-prefix=CHECK --check-prefix=DISABLE
;
; Note: Lots of tests use inline asm instead of regular calls.
; This allows to have a better control on what the allocation will do.
; Otherwise, we may have spill right in the entry block, defeating
; shrink-wrapping. Moreover, some of the inline asm statements (nop)
; are here to ensure that the related paths do not end up as critical
; edges.
; Also disable the late if-converter as it makes harder to reason on
; the diffs.
; Initial motivating example: Simple diamond with a call just on one side.
; CHECK-LABEL: foo:
;
; Compare the arguments and jump to exit.
; No prologue needed.
; ENABLE: cmp r0, r1
; ENABLE-NEXT: bge [[EXIT_LABEL:LBB[0-9_]+]]
;
; Prologue code.
; CHECK: push {r7, lr}
; CHECK-NEXT: sub sp, #8
;
; Compare the arguments and jump to exit.
; After the prologue is set.
; DISABLE: cmp r0, r1
; DISABLE-NEXT: bge [[EXIT_LABEL:LBB[0-9_]+]]
;
; Store %a in the alloca.
; CHECK: str r0, [sp, #4]
; Set the alloca address in the second argument.
; Set the first argument to zero.
; CHECK: movs r0, #0
; CHECK-NEXT: add r1, sp, #4
; CHECK-NEXT: bl
;
; With shrink-wrapping, epilogue is just after the call.
; ENABLE-NEXT: add sp, #8
; ENABLE-NEXT: pop {r7, lr}
;
; CHECK: [[EXIT_LABEL]]:
;
; Without shrink-wrapping, epilogue is in the exit block.
; Epilogue code. (What we pop does not matter.)
; DISABLE: add sp, #8
; DISABLE-NEXT: pop {r7, pc}
;
; ENABLE-NEXT: bx lr
define i32 @foo(i32 %a, i32 %b) {
%tmp = alloca i32, align 4
%tmp2 = icmp slt i32 %a, %b
br i1 %tmp2, label %true, label %false
true:
store i32 %a, i32* %tmp, align 4
%tmp4 = call i32 @doSomething(i32 0, i32* %tmp)
br label %false
false:
%tmp.0 = phi i32 [ %tmp4, %true ], [ %a, %0 ]
ret i32 %tmp.0
}
; Function Attrs: optsize
declare i32 @doSomething(i32, i32*)
; Check that we do not perform the restore inside the loop whereas the save
; is outside.
; CHECK-LABEL: freqSaveAndRestoreOutsideLoop:
;
; Shrink-wrapping allows to skip the prologue in the else case.
; ENABLE: cmp r0, #0
; ENABLE-NEXT: beq [[ELSE_LABEL:LBB[0-9_]+]]
;
; Prologue code.
; Make sure we save the CSR used in the inline asm: r4.
; CHECK: push {r4, lr}
;
; DISABLE: cmp r0, #0
; DISABLE-NEXT: beq [[ELSE_LABEL:LBB[0-9_]+]]
;
; SUM is in r0 because it is coalesced with the second
; argument on the else path.
; CHECK: movs [[SUM:r0]], #0
; CHECK-NEXT: movs [[IV:r[0-9]+]], #10
;
; Next BB.
; CHECK: [[LOOP:LBB[0-9_]+]]: @ %for.body
; CHECK: movs [[TMP:r[0-9]+]], #1
; CHECK: adds [[SUM]], [[TMP]], [[SUM]]
; CHECK-NEXT: subs [[IV]], [[IV]], #1
; CHECK-NEXT: cmp [[IV]], #0
; CHECK-NEXT: bne [[LOOP]]
;
; Next BB.
; SUM << 3.
; CHECK: lsls [[SUM]], [[SUM]], #3
;
; Duplicated epilogue.
; DISABLE: pop {r4, pc}
;
; CHECK: [[ELSE_LABEL]]: @ %if.else
; Shift second argument by one and store into returned register.
; CHECK: lsls r0, r1, #1
; DISABLE-NEXT: pop {r4, pc}
;
; ENABLE-NEXT: bx lr
define i32 @freqSaveAndRestoreOutsideLoop(i32 %cond, i32 %N) {
entry:
%tobool = icmp eq i32 %cond, 0
br i1 %tobool, label %if.else, label %for.preheader
for.preheader:
tail call void asm "nop", ""()
br label %for.body
for.body: ; preds = %entry, %for.body
%i.05 = phi i32 [ %inc, %for.body ], [ 0, %for.preheader ]
%sum.04 = phi i32 [ %add, %for.body ], [ 0, %for.preheader ]
%call = tail call i32 asm sideeffect "movs $0, #1", "=r,~{r4}"()
%add = add nsw i32 %call, %sum.04
%inc = add nuw nsw i32 %i.05, 1
%exitcond = icmp eq i32 %inc, 10
br i1 %exitcond, label %for.end, label %for.body
for.end: ; preds = %for.body
%shl = shl i32 %add, 3
br label %if.end
if.else: ; preds = %entry
%mul = shl nsw i32 %N, 1
br label %if.end
if.end: ; preds = %if.else, %for.end
%sum.1 = phi i32 [ %shl, %for.end ], [ %mul, %if.else ]
ret i32 %sum.1
}
declare i32 @something(...)
; Check that we do not perform the shrink-wrapping inside the loop even
; though that would be legal. The cost model must prevent that.
; CHECK-LABEL: freqSaveAndRestoreOutsideLoop2:
; Prologue code.
; Make sure we save the CSR used in the inline asm: r4.
; CHECK: push {r4
; This is the nop.
; CHECK: mov r8, r8
; CHECK: movs [[SUM:r0]], #0
; CHECK-NEXT: movs [[IV:r[0-9]+]], #10
; Next BB.
; CHECK: [[LOOP_LABEL:LBB[0-9_]+]]: @ %for.body
; CHECK: movs [[TMP:r[0-9]+]], #1
; CHECK: adds [[SUM]], [[TMP]], [[SUM]]
; CHECK-NEXT: subs [[IV]], [[IV]], #1
; CHECK-NEXT: cmp [[IV]], #0
; CHECK-NEXT: bne [[LOOP_LABEL]]
; Next BB.
; CHECK: @ %for.exit
; This is the nop.
; CHECK: mov r8, r8
; CHECK: pop {r4
define i32 @freqSaveAndRestoreOutsideLoop2(i32 %cond) {
entry:
br label %for.preheader
for.preheader:
tail call void asm "nop", ""()
br label %for.body
for.body: ; preds = %for.body, %entry
%i.04 = phi i32 [ 0, %for.preheader ], [ %inc, %for.body ]
%sum.03 = phi i32 [ 0, %for.preheader ], [ %add, %for.body ]
%call = tail call i32 asm sideeffect "movs $0, #1", "=r,~{r4}"()
%add = add nsw i32 %call, %sum.03
%inc = add nuw nsw i32 %i.04, 1
%exitcond = icmp eq i32 %inc, 10
br i1 %exitcond, label %for.exit, label %for.body
for.exit:
tail call void asm "nop", ""()
br label %for.end
for.end: ; preds = %for.body
ret i32 %add
}
; Check with a more complex case that we do not have save within the loop and
; restore outside.
; CHECK-LABEL: loopInfoSaveOutsideLoop:
;
; ENABLE: cmp r0, #0
; ENABLE-NEXT: beq [[ELSE_LABEL:LBB[0-9_]+]]
;
; Prologue code.
; Make sure we save the CSR used in the inline asm: r4.
; CHECK: push {r4, lr}
;
; DISABLE: cmp r0, #0
; DISABLE-NEXT: beq [[ELSE_LABEL:LBB[0-9_]+]]
;
; SUM is in r0 because it is coalesced with the second
; argument on the else path.
; CHECK: movs [[SUM:r0]], #0
; CHECK-NEXT: movs [[IV:r[0-9]+]], #10
;
; Next BB.
; CHECK: [[LOOP:LBB[0-9_]+]]: @ %for.body
; CHECK: movs [[TMP:r[0-9]+]], #1
; CHECK: adds [[SUM]], [[TMP]], [[SUM]]
; CHECK-NEXT: subs [[IV]], [[IV]], #1
; CHECK-NEXT: cmp [[IV]], #0
; CHECK-NEXT: bne [[LOOP]]
;
; Next BB.
; SUM << 3.
; CHECK: lsls [[SUM]], [[SUM]], #3
; ENABLE-NEXT: pop {r4, lr}
;
; Duplicated epilogue.
; DISABLE: pop {r4, pc}
;
; CHECK: [[ELSE_LABEL]]: @ %if.else
; Shift second argument by one and store into returned register.
; CHECK: lsls r0, r1, #1
; DISABLE-NEXT: pop {r4, pc}
;
; ENABLE-NEXT: bx lr
define i32 @loopInfoSaveOutsideLoop(i32 %cond, i32 %N) {
entry:
%tobool = icmp eq i32 %cond, 0
br i1 %tobool, label %if.else, label %for.preheader
for.preheader:
tail call void asm "nop", ""()
br label %for.body
for.body: ; preds = %entry, %for.body
%i.05 = phi i32 [ %inc, %for.body ], [ 0, %for.preheader ]
%sum.04 = phi i32 [ %add, %for.body ], [ 0, %for.preheader ]
%call = tail call i32 asm sideeffect "movs $0, #1", "=r,~{r4}"()
%add = add nsw i32 %call, %sum.04
%inc = add nuw nsw i32 %i.05, 1
%exitcond = icmp eq i32 %inc, 10
br i1 %exitcond, label %for.end, label %for.body
for.end: ; preds = %for.body
tail call void asm "nop", "~{r4}"()
%shl = shl i32 %add, 3
br label %if.end
if.else: ; preds = %entry
%mul = shl nsw i32 %N, 1
br label %if.end
if.end: ; preds = %if.else, %for.end
%sum.1 = phi i32 [ %shl, %for.end ], [ %mul, %if.else ]
ret i32 %sum.1
}
declare void @somethingElse(...)
; Check with a more complex case that we do not have restore within the loop and
; save outside.
; CHECK-LABEL: loopInfoRestoreOutsideLoop:
;
; ENABLE: cmp r0, #0
; ENABLE-NEXT: beq [[ELSE_LABEL:LBB[0-9_]+]]
;
; Prologue code.
; Make sure we save the CSR used in the inline asm: r4.
; CHECK: push {r4, lr}
;
; DISABLE-NEXT: cmp r0, #0
; DISABLE-NEXT: beq [[ELSE_LABEL:LBB[0-9_]+]]
;
; SUM is in r0 because it is coalesced with the second
; argument on the else path.
; CHECK: movs [[SUM:r0]], #0
; CHECK-NEXT: movs [[IV:r[0-9]+]], #10
;
; Next BB.
; CHECK: [[LOOP:LBB[0-9_]+]]: @ %for.body
; CHECK: movs [[TMP:r[0-9]+]], #1
; CHECK: adds [[SUM]], [[TMP]], [[SUM]]
; CHECK-NEXT: subs [[IV]], [[IV]], #1
; CHECK-NEXT: cmp [[IV]], #0
; CHECK-NEXT: bne [[LOOP]]
;
; Next BB.
; SUM << 3.
; CHECK: lsls [[SUM]], [[SUM]], #3
; ENABLE: pop {r4, lr}
;
; Duplicated epilogue.
; DISABLE: pop {r4, pc}
;
; CHECK: [[ELSE_LABEL]]: @ %if.else
; Shift second argument by one and store into returned register.
; CHECK: lsls r0, r1, #1
; DISABLE-NEXT: pop {r4, pc}
;
; ENABLE-NEXT: bx lr
define i32 @loopInfoRestoreOutsideLoop(i32 %cond, i32 %N) #0 {
entry:
%tobool = icmp eq i32 %cond, 0
br i1 %tobool, label %if.else, label %if.then
if.then: ; preds = %entry
tail call void asm "nop", "~{r4}"()
br label %for.body
for.body: ; preds = %for.body, %if.then
%i.05 = phi i32 [ 0, %if.then ], [ %inc, %for.body ]
%sum.04 = phi i32 [ 0, %if.then ], [ %add, %for.body ]
%call = tail call i32 asm sideeffect "movs $0, #1", "=r,~{r4}"()
%add = add nsw i32 %call, %sum.04
%inc = add nuw nsw i32 %i.05, 1
%exitcond = icmp eq i32 %inc, 10
br i1 %exitcond, label %for.end, label %for.body
for.end: ; preds = %for.body
%shl = shl i32 %add, 3
br label %if.end
if.else: ; preds = %entry
%mul = shl nsw i32 %N, 1
br label %if.end
if.end: ; preds = %if.else, %for.end
%sum.1 = phi i32 [ %shl, %for.end ], [ %mul, %if.else ]
ret i32 %sum.1
}
; Check that we handle function with no frame information correctly.
; CHECK-LABEL: emptyFrame:
; CHECK: @ %entry
; CHECK-NEXT: movs r0, #0
; CHECK-NEXT: bx lr
define i32 @emptyFrame() {
entry:
ret i32 0
}
; Check that we handle inline asm correctly.
; CHECK-LABEL: inlineAsm:
;
; ENABLE: cmp r0, #0
; ENABLE-NEXT: beq [[ELSE_LABEL:LBB[0-9_]+]]
;
; Prologue code.
; Make sure we save the CSR used in the inline asm: r4.
; CHECK: push {r4, lr}
;
; DISABLE: cmp r0, #0
; DISABLE-NEXT: beq [[ELSE_LABEL:LBB[0-9_]+]]
;
; CHECK: movs [[IV:r[0-9]+]], #10
;
; Next BB.
; CHECK: [[LOOP:LBB[0-9_]+]]: @ %for.body
; CHECK: movs r4, #1
; CHECK: subs [[IV]], [[IV]], #1
; CHECK-NEXT: cmp [[IV]], #0
; CHECK-NEXT: bne [[LOOP]]
;
; Next BB.
; CHECK: movs r0, #0
; ENABLE-NEXT: pop {r4, lr}
;
; Duplicated epilogue.
; DISABLE-NEXT: pop {r4, pc}
;
; CHECK: [[ELSE_LABEL]]: @ %if.else
; Shift second argument by one and store into returned register.
; CHECK: lsls r0, r1, #1
; DISABLE-NEXT: pop {r4, pc}
;
; ENABLE-NEXT: bx lr
define i32 @inlineAsm(i32 %cond, i32 %N) {
entry:
%tobool = icmp eq i32 %cond, 0
br i1 %tobool, label %if.else, label %for.preheader
for.preheader:
tail call void asm "nop", ""()
br label %for.body
for.body: ; preds = %entry, %for.body
%i.03 = phi i32 [ %inc, %for.body ], [ 0, %for.preheader ]
tail call void asm sideeffect "movs r4, #1", "~{r4}"()
%inc = add nuw nsw i32 %i.03, 1
%exitcond = icmp eq i32 %inc, 10
br i1 %exitcond, label %for.exit, label %for.body
for.exit:
tail call void asm "nop", ""()
br label %if.end
if.else: ; preds = %entry
%mul = shl nsw i32 %N, 1
br label %if.end
if.end: ; preds = %for.body, %if.else
%sum.0 = phi i32 [ %mul, %if.else ], [ 0, %for.exit ]
ret i32 %sum.0
}
; Check that we handle calls to variadic functions correctly.
; CHECK-LABEL: callVariadicFunc:
;
; ENABLE: cmp r0, #0
; ENABLE-NEXT: beq [[ELSE_LABEL:LBB[0-9_]+]]
;
; Prologue code.
; CHECK: push {[[TMP:r[0-9]+]], lr}
; CHECK-NEXT: sub sp, #16
;
; DISABLE: cmp r0, #0
; DISABLE-NEXT: beq [[ELSE_LABEL:LBB[0-9_]+]]
;
; Setup of the varags.
; CHECK: mov [[TMP_SP:r[0-9]+]], sp
; CHECK-NEXT: str r1, {{\[}}[[TMP_SP]]]
; CHECK-NEXT: str r1, {{\[}}[[TMP_SP]], #4]
; CHECK-NEXT: str r1, {{\[}}[[TMP_SP]], #8]
; Thumb has quite a strange way for moving stuff
; in around. Oh well, match the current sequence.
; CHECK: push {r1}
; CHECK-NEXT: pop {r0}
; CHECK: push {r1}
; CHECK-NEXT: pop {r2}
; CHECK: push {r1}
; CHECK-NEXT: pop {r3}
; CHECK-NEXT: bl
; CHECK-NEXT: lsls r0, r0, #3
; CHECK-NEXT: add sp, #16
;
; ENABLE-NEXT: pop {[[TMP]], lr}
;
; Duplicated epilogue.
; DISABLE-NEXT: pop {[[TMP]], pc}
;
; CHECK: [[ELSE_LABEL]]: @ %if.else
; Shift second argument by one and store into returned register.
; CHECK: lsls r0, r1, #1
;
; Epilogue code.
; ENABLE-NEXT: bx lr
;
; DISABLE-NEXT: add sp, #16
; DISABLE-NEXT: pop {[[TMP]], pc}
define i32 @callVariadicFunc(i32 %cond, i32 %N) {
entry:
%tobool = icmp eq i32 %cond, 0
br i1 %tobool, label %if.else, label %if.then
if.then: ; preds = %entry
%call = tail call i32 (i32, ...) @someVariadicFunc(i32 %N, i32 %N, i32 %N, i32 %N, i32 %N, i32 %N, i32 %N)
%shl = shl i32 %call, 3
br label %if.end
if.else: ; preds = %entry
%mul = shl nsw i32 %N, 1
br label %if.end
if.end: ; preds = %if.else, %if.then
%sum.0 = phi i32 [ %shl, %if.then ], [ %mul, %if.else ]
ret i32 %sum.0
}
declare i32 @someVariadicFunc(i32, ...)
; Make sure we do not insert unreachable code after noreturn function.
; Although this is not incorrect to insert such code, it is useless
; and it hurts the binary size.
;
; CHECK-LABEL: noreturn:
; DISABLE: push
;
; CHECK: movs [[TMP:r[0-9]+]], #255
; CHECK-NEXT: tst r0, [[TMP]]
; CHECK-NEXT: bne [[ABORT:LBB[0-9_]+]]
;
; CHECK: movs r0, #42
;
; ENABLE-NEXT: bx lr
;
; DISABLE-NEXT: pop
;;
; CHECK: [[ABORT]]: @ %if.abort
;
; ENABLE: push
;
; CHECK: bl
; ENABLE-NOT: pop
define i32 @noreturn(i8 signext %bad_thing) {
entry:
%tobool = icmp eq i8 %bad_thing, 0
br i1 %tobool, label %if.end, label %if.abort
if.abort:
%call = tail call i32 asm sideeffect "movs $0, #1", "=r,~{r4}"()
tail call void @abort() #0
unreachable
if.end:
ret i32 42
}
declare void @abort() #0
attributes #0 = { noreturn nounwind }