[llvm] r242908 - [ARM] Make the frame lowering code ready for shrink-wrapping.
Quentin Colombet
qcolombet at apple.com
Wed Jul 22 09:34:38 PDT 2015
Author: qcolombet
Date: Wed Jul 22 11:34:37 2015
New Revision: 242908
URL: http://llvm.org/viewvc/llvm-project?rev=242908&view=rev
Log:
[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>
Added:
llvm/trunk/test/CodeGen/ARM/arm-shrink-wrapping.ll
llvm/trunk/test/CodeGen/Thumb/thumb-shrink-wrapping.ll
Modified:
llvm/trunk/lib/Target/ARM/ARMFrameLowering.cpp
llvm/trunk/lib/Target/ARM/Thumb1FrameLowering.cpp
llvm/trunk/lib/Target/ARM/Thumb1FrameLowering.h
Modified: llvm/trunk/lib/Target/ARM/ARMFrameLowering.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/ARM/ARMFrameLowering.cpp?rev=242908&r1=242907&r2=242908&view=diff
==============================================================================
--- llvm/trunk/lib/Target/ARM/ARMFrameLowering.cpp (original)
+++ llvm/trunk/lib/Target/ARM/ARMFrameLowering.cpp Wed Jul 22 11:34:37 2015
@@ -288,7 +288,6 @@ static void emitAligningInstructions(Mac
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::adjustForSegmente
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();
Modified: llvm/trunk/lib/Target/ARM/Thumb1FrameLowering.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/ARM/Thumb1FrameLowering.cpp?rev=242908&r1=242907&r2=242908&view=diff
==============================================================================
--- llvm/trunk/lib/Target/ARM/Thumb1FrameLowering.cpp (original)
+++ llvm/trunk/lib/Target/ARM/Thumb1FrameLowering.cpp Wed Jul 22 11:34:37 2015
@@ -85,7 +85,6 @@ eliminateCallFramePseudoInstr(MachineFun
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(M
}
}
+ 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();
-
- // 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;
- }
+ return IsV4PopReturn && STI.hasV4TOps() && !STI.hasV5TOps();
+}
- // 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]);
+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());
- 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);
- }
+ // 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;
+ }
- // 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;
+ // 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]);
+
+ 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;
}
+ // Otherwise, remember that the register will be available to
+ // save a pop-friendly register.
+ TemporaryReg = Register;
}
+ }
- 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));
- }
+ if (!DoIt && !PopReg && !TemporaryReg)
+ return false;
- 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;
- }
+ 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(ARM::LR, RegState::Define)
+ .addReg(TemporaryReg, 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));
- }
+ 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(MachineBasic
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);
Modified: llvm/trunk/lib/Target/ARM/Thumb1FrameLowering.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/ARM/Thumb1FrameLowering.h?rev=242908&r1=242907&r2=242908&view=diff
==============================================================================
--- llvm/trunk/lib/Target/ARM/Thumb1FrameLowering.h (original)
+++ llvm/trunk/lib/Target/ARM/Thumb1FrameLowering.h Wed Jul 22 11:34:37 2015
@@ -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
Added: llvm/trunk/test/CodeGen/ARM/arm-shrink-wrapping.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/CodeGen/ARM/arm-shrink-wrapping.ll?rev=242908&view=auto
==============================================================================
--- llvm/trunk/test/CodeGen/ARM/arm-shrink-wrapping.ll (added)
+++ llvm/trunk/test/CodeGen/ARM/arm-shrink-wrapping.ll Wed Jul 22 11:34:37 2015
@@ -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 }
Added: llvm/trunk/test/CodeGen/Thumb/thumb-shrink-wrapping.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/CodeGen/Thumb/thumb-shrink-wrapping.ll?rev=242908&view=auto
==============================================================================
--- llvm/trunk/test/CodeGen/Thumb/thumb-shrink-wrapping.ll (added)
+++ llvm/trunk/test/CodeGen/Thumb/thumb-shrink-wrapping.ll Wed Jul 22 11:34:37 2015
@@ -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 }
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