# RUN: llc -mtriple=thumbv8.1m.main %s -run-pass=arm-low-overhead-loops --verify-machineinstrs -o -
# CHECK: bb.1.for.body.preheader:
# CHECK: $lr = t2DLS
# CHECK-NOT: t2LoopDec
# CHECK: bb.6.for.inc:
# CHECK: $lr = t2LEUpdate renamable $lr, %bb.2
--- |
; ModuleID = 'switch.ll'
source_filename = "switch.ll"
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 dso_local arm_aapcscc i32 @search(i8* nocapture readonly %c, i32 %N) {
entry:
%cmp11 = icmp eq i32 %N, 0
br i1 %cmp11, label %for.cond.cleanup, label %for.body.preheader
for.body.preheader: ; preds = %entry
%start = call i32 @llvm.start.loop.iterations.i32(i32 %N)
br label %for.body
for.cond.cleanup: ; preds = %for.inc, %entry
%found.0.lcssa = phi i32 [ 0, %entry ], [ %found.1, %for.inc ]
%spaces.0.lcssa = phi i32 [ 0, %entry ], [ %spaces.1, %for.inc ]
%sub = sub nsw i32 %found.0.lcssa, %spaces.0.lcssa
ret i32 %sub
for.body: ; preds = %for.inc, %for.body.preheader
%lsr.iv1 = phi i8* [ %c, %for.body.preheader ], [ %scevgep, %for.inc ]
%spaces.013 = phi i32 [ %spaces.1, %for.inc ], [ 0, %for.body.preheader ]
%found.012 = phi i32 [ %found.1, %for.inc ], [ 0, %for.body.preheader ]
%0 = phi i32 [ %start, %for.body.preheader ], [ %3, %for.inc ]
%1 = load i8, i8* %lsr.iv1, align 1
%2 = zext i8 %1 to i32
switch i32 %2, label %for.inc [
i32 108, label %sw.bb
i32 111, label %sw.bb
i32 112, label %sw.bb
i32 32, label %sw.bb1
]
sw.bb: ; preds = %for.body, %for.body, %for.body
%inc = add nsw i32 %found.012, 1
br label %for.inc
sw.bb1: ; preds = %for.body
%inc2 = add nsw i32 %spaces.013, 1
br label %for.inc
for.inc: ; preds = %sw.bb1, %sw.bb, %for.body
%found.1 = phi i32 [ %found.012, %for.body ], [ %found.012, %sw.bb1 ], [ %inc, %sw.bb ]
%spaces.1 = phi i32 [ %spaces.013, %for.body ], [ %inc2, %sw.bb1 ], [ %spaces.013, %sw.bb ]
%scevgep = getelementptr i8, i8* %lsr.iv1, i32 1
%3 = call i32 @llvm.loop.decrement.reg.i32.i32.i32(i32 %0, i32 1)
%4 = icmp ne i32 %3, 0
br i1 %4, label %for.body, label %for.cond.cleanup
}
; Function Attrs: noduplicate nounwind
declare i32 @llvm.start.loop.iterations.i32(i32) #0
; Function Attrs: noduplicate nounwind
declare i32 @llvm.loop.decrement.reg.i32.i32.i32(i32, i32) #0
; Function Attrs: nounwind
declare void @llvm.stackprotector(i8*, i8**) #1
attributes #0 = { noduplicate nounwind }
attributes #1 = { nounwind }
...
---
name: search
alignment: 2
exposesReturnsTwice: false
legalized: false
regBankSelected: false
selected: false
failedISel: false
tracksRegLiveness: true
hasWinCFI: false
registers: []
liveins:
- { reg: '$r0', virtual-reg: '' }
- { reg: '$r1', virtual-reg: '' }
frameInfo:
isFrameAddressTaken: false
isReturnAddressTaken: false
hasStackMap: false
hasPatchPoint: false
stackSize: 8
offsetAdjustment: 0
maxAlignment: 4
adjustsStack: false
hasCalls: false
stackProtector: ''
maxCallFrameSize: 0
cvBytesOfCalleeSavedRegisters: 0
hasOpaqueSPAdjustment: false
hasVAStart: false
hasMustTailInVarArgFunc: false
localFrameSize: 0
savePoint: ''
restorePoint: ''
fixedStack: []
stack:
- { id: 0, name: '', type: spill-slot, offset: -4, size: 4, alignment: 4,
stack-id: default, callee-saved-register: '$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: '$r4', callee-saved-restored: true,
debug-info-variable: '', debug-info-expression: '', debug-info-location: '' }
callSites: []
constants: []
machineFunctionInfo: {}
body: |
bb.0.entry:
successors: %bb.7(0x30000000), %bb.1(0x50000000)
liveins: $r0, $r1, $r4, $lr
frame-setup tPUSH 14, $noreg, killed $r4, killed $lr, implicit-def $sp, implicit $sp
frame-setup CFI_INSTRUCTION def_cfa_offset 8
frame-setup CFI_INSTRUCTION offset $lr, -4
frame-setup CFI_INSTRUCTION offset $r4, -8
tCBZ $r1, %bb.7
bb.1.for.body.preheader:
successors: %bb.4(0x80000000)
liveins: $r0, $r1
$lr = tMOVr $r1, 14, $noreg
$lr = t2DoLoopStart killed $r1
renamable $r1, dead $cpsr = tMOVi8 0, 14, $noreg
renamable $r12 = t2MOVi 1, 14, $noreg, $noreg
renamable $r2, dead $cpsr = tMOVi8 0, 14, $noreg
tB %bb.4, 14, $noreg
bb.2.for.body:
successors: %bb.3(0x80000000)
liveins: $lr, $r0, $r1, $r2, $r3, $r12
tCMPi8 killed renamable $r3, 32, 14, $noreg, implicit-def $cpsr
t2IT 0, 8, implicit-def $itstate
renamable $r1 = nsw tADDi8 $noreg, killed renamable $r1, 1, 0, killed $cpsr, implicit $r1, implicit killed $itstate
bb.3.for.inc:
successors: %bb.4(0x7c000000), %bb.8(0x04000000)
liveins: $lr, $r0, $r1, $r2, $r12
renamable $r0, dead $cpsr = tADDi8 killed renamable $r0, 1, 14, $noreg
renamable $lr = t2LoopDec killed renamable $lr, 1
t2LoopEnd renamable $lr, %bb.4, implicit-def dead $cpsr
tB %bb.8, 14, $noreg
bb.4.for.body:
successors: %bb.2(0x26666665), %bb.5(0x5999999b)
liveins: $lr, $r0, $r1, $r2, $r12
renamable $r3 = tLDRBi renamable $r0, 0, 14, $noreg :: (load (s8) from %ir.lsr.iv1)
renamable $r4 = t2SUBri renamable $r3, 108, 14, $noreg, $noreg
tCMPi8 renamable $r4, 4, 14, $noreg, implicit-def $cpsr
tBcc %bb.2, 8, killed $cpsr
bb.5.for.body:
successors: %bb.6(0x6db6db6e), %bb.2(0x12492492)
liveins: $lr, $r0, $r1, $r2, $r3, $r4, $r12
renamable $r4 = t2LSLrr renamable $r12, killed renamable $r4, 14, $noreg, $noreg
t2TSTri killed renamable $r4, 25, 14, $noreg, implicit-def $cpsr
tBcc %bb.2, 0, killed $cpsr
bb.6.sw.bb:
successors: %bb.3(0x80000000)
liveins: $lr, $r0, $r1, $r2, $r12
renamable $r2, dead $cpsr = nsw tADDi8 killed renamable $r2, 1, 14, $noreg
tB %bb.3, 14, $noreg
bb.7:
successors: %bb.8(0x80000000)
renamable $r2, dead $cpsr = tMOVi8 0, 14, $noreg
renamable $r1, dead $cpsr = tMOVi8 0, 14, $noreg
bb.8.for.cond.cleanup:
liveins: $r1, $r2
renamable $r0, dead $cpsr = nsw tSUBrr killed renamable $r2, killed renamable $r1, 14, $noreg
tPOP_RET 14, $noreg, def $r4, def $pc, implicit killed $r0
...