# RUN: llc -mtriple=thumbv8.1m.main %s -run-pass=arm-low-overhead-loops --verify-machineinstrs -o - | FileCheck %s
# CHECK: while.body:
# CHECK-NOT: t2DLS
# CHECK-NOT: t2LEUpdate
--- |
target datalayout = "e-m:e-p:32:32-Fi8-i64:64-v128:64:128-a:0:32-n32-S64"
target triple = "thumbv8.1m.main"
define i32 @skip_spill(i32 %n) #0 {
entry:
%cmp6 = icmp eq i32 %n, 0
br i1 %cmp6, label %while.end, label %while.body.preheader
while.body.preheader: ; preds = %entry
%start = call i32 @llvm.start.loop.iterations.i32(i32 %n)
br label %while.body
while.body: ; preds = %while.body, %while.body.preheader
%res.07 = phi i32 [ %add, %while.body ], [ 0, %while.body.preheader ]
%0 = phi i32 [ %start, %while.body.preheader ], [ %1, %while.body ]
%call = tail call i32 @bar()
%add = add nsw i32 %call, %res.07
%1 = call i32 @llvm.loop.decrement.reg.i32.i32.i32(i32 %0, i32 1)
%2 = icmp ne i32 %1, 0
br i1 %2, label %while.body, label %while.end
while.end: ; preds = %while.body, %entry
%res.0.lcssa = phi i32 [ 0, %entry ], [ %add, %while.body ]
ret i32 %res.0.lcssa
}
declare i32 @bar(...) local_unnamed_addr #0
declare i32 @llvm.start.loop.iterations.i32(i32) #1
declare i32 @llvm.loop.decrement.reg.i32.i32.i32(i32, i32) #1
attributes #0 = { "target-features"="+mve.fp" }
attributes #1 = { noduplicate nounwind }
attributes #2 = { nounwind }
...
---
name: skip_spill
alignment: 2
exposesReturnsTwice: false
legalized: false
regBankSelected: false
selected: false
failedISel: false
tracksRegLiveness: true
hasWinCFI: false
registers: []
liveins:
- { reg: '$r0', virtual-reg: '' }
frameInfo:
isFrameAddressTaken: false
isReturnAddressTaken: false
hasStackMap: false
hasPatchPoint: false
stackSize: 16
offsetAdjustment: 0
maxAlignment: 4
adjustsStack: true
hasCalls: true
stackProtector: ''
maxCallFrameSize: 0
cvBytesOfCalleeSavedRegisters: 0
hasOpaqueSPAdjustment: false
hasVAStart: false
hasMustTailInVarArgFunc: false
localFrameSize: 0
savePoint: ''
restorePoint: ''
fixedStack: []
stack:
- { id: 0, name: '', type: spill-slot, offset: -4, size: 4, alignment: 4,
stack-id: default, callee-saved-register: '$lr', callee-saved-restored: false,
debug-info-variable: '', debug-info-expression: '', debug-info-location: '' }
- { id: 1, name: '', type: spill-slot, offset: -8, size: 4, alignment: 4,
stack-id: default, callee-saved-register: '$r7', callee-saved-restored: true,
debug-info-variable: '', debug-info-expression: '', debug-info-location: '' }
- { id: 2, name: '', type: spill-slot, offset: -12, size: 4, alignment: 4,
stack-id: default, callee-saved-register: '$r5', callee-saved-restored: true,
debug-info-variable: '', debug-info-expression: '', debug-info-location: '' }
- { id: 3, name: '', type: spill-slot, offset: -16, size: 4, alignment: 4,
stack-id: default, callee-saved-register: '$r4', callee-saved-restored: true,
debug-info-variable: '', debug-info-expression: '', debug-info-location: '' }
callSites: []
constants: []
machineFunctionInfo: {}
body: |
bb.0.entry:
successors: %bb.4(0x30000000), %bb.1(0x50000000)
liveins: $r0, $r4, $r5, $r7, $lr
frame-setup tPUSH 14, $noreg, killed $r4, killed $r5, killed $r7, killed $lr, implicit-def $sp, implicit $sp
frame-setup CFI_INSTRUCTION def_cfa_offset 16
frame-setup CFI_INSTRUCTION offset $lr, -4
frame-setup CFI_INSTRUCTION offset $r7, -8
frame-setup CFI_INSTRUCTION offset $r5, -12
frame-setup CFI_INSTRUCTION offset $r4, -16
tCBZ $r0, %bb.4
bb.1.while.body.preheader:
successors: %bb.2(0x80000000)
liveins: $r0
$lr = tMOVr $r0, 14, $noreg
renamable $r4, dead $cpsr = tMOVi8 0, 14, $noreg
$lr = t2DoLoopStart killed $r0
bb.2.while.body:
successors: %bb.2(0x7c000000), %bb.3(0x04000000)
liveins: $lr, $r4
$r5 = tMOVr killed $lr, 14, $noreg
tBL 14, $noreg, @bar, csr_aapcs, implicit-def dead $lr, implicit $sp, implicit-def $sp, implicit-def $r0
$lr = tMOVr killed $r5, 14, $noreg
renamable $r4 = nsw tADDhirr killed renamable $r4, killed renamable $r0, 14, $noreg
renamable $lr = t2LoopDec killed renamable $lr, 1
t2LoopEnd renamable $lr, %bb.2, implicit-def dead $cpsr
tB %bb.3, 14, $noreg
bb.3.while.end:
liveins: $r4
$r0 = tMOVr killed $r4, 14, $noreg
tPOP_RET 14, $noreg, def $r4, def $r5, def $r7, def $pc, implicit killed $r0
bb.4:
renamable $r4, dead $cpsr = tMOVi8 0, 14, $noreg
$r0 = tMOVr killed $r4, 14, $noreg
tPOP_RET 14, $noreg, def $r4, def $r5, def $r7, def $pc, implicit killed $r0
...
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