# RUN: llc -mtriple=thumbv8.1m.main -run-pass=arm-low-overhead-loops %s --verify-machineinstrs -o - | FileCheck %s
# CHECK: name: non_loop
# CHECK: bb.0.entry:
# CHECK: tBcc %bb.2, 3
# CHECK: bb.1.not.preheader:
# CHECK: $lr = t2SUBri killed renamable $lr, 0, 14
# CHECK: tBcc %bb.4, 0
# CHECK: tB %bb.2
# CHECK: bb.3.while.body:
# CHECK: t2CMPri renamable $lr, 0, 14
# CHECK: tBcc %bb.3, 1
# CHECK: tB %bb.4
# CHECK: bb.4.while.end:
--- |
target datalayout = "e-m:e-p:32:32-Fi8-i64:64-v128:64:128-a:0:32-n32-S64"
target triple = "thumbv8.1m.main"
define void @non_loop(ptr nocapture %a, ptr nocapture readonly %b, i32 %N) {
entry:
%cmp = icmp ugt i32 %N, 2
br i1 %cmp, label %not.preheader, label %while.body.preheader
not.preheader: ; preds = %entry
%test = call i1 @llvm.test.set.loop.iterations.i32(i32 %N)
br i1 %test, label %while.body.preheader, label %while.end
while.body.preheader: ; preds = %not.preheader, %entry
%scevgep = getelementptr i16, ptr %a, i32 -1
%scevgep3 = getelementptr i16, ptr %b, i32 -1
br label %while.body
while.body: ; preds = %while.body, %while.body.preheader
%lsr.iv4 = phi ptr [ %scevgep3, %while.body.preheader ], [ %scevgep5, %while.body ]
%lsr.iv = phi ptr [ %scevgep, %while.body.preheader ], [ %scevgep1, %while.body ]
%count = phi i32 [ %count.next, %while.body ], [ %N, %while.body.preheader ]
%scevgep7 = getelementptr i16, ptr %lsr.iv, i32 1
%scevgep4 = getelementptr i16, ptr %lsr.iv4, i32 1
%load = load i16, ptr %scevgep4, align 2
store i16 %load, ptr %scevgep7, align 2
%count.next = call i32 @llvm.loop.decrement.reg.i32.i32.i32(i32 %count, i32 1)
%cmp1 = icmp ne i32 %count.next, 0
%scevgep1 = getelementptr i16, ptr %lsr.iv, i32 1
%scevgep5 = getelementptr i16, ptr %lsr.iv4, i32 1
br i1 %cmp1, label %while.body, label %while.end
while.end: ; preds = %while.body, %not.preheader
ret void
}
declare i1 @llvm.test.set.loop.iterations.i32(i32) #0
declare i32 @llvm.loop.decrement.reg.i32.i32.i32(i32, i32) #0
declare void @llvm.stackprotector(ptr, ptr) #1
attributes #0 = { noduplicate nounwind }
attributes #1 = { nounwind }
...
---
name: non_loop
alignment: 2
exposesReturnsTwice: false
legalized: false
regBankSelected: false
selected: false
failedISel: false
tracksRegLiveness: true
hasWinCFI: false
registers: []
liveins:
- { reg: '$r0', virtual-reg: '' }
- { reg: '$r1', virtual-reg: '' }
- { reg: '$r2', 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: '$lr', callee-saved-restored: false,
debug-info-variable: '', debug-info-expression: '', debug-info-location: '' }
- { id: 1, name: '', type: spill-slot, offset: -8, size: 4, alignment: 4,
stack-id: default, callee-saved-register: '$r7', callee-saved-restored: true,
debug-info-variable: '', debug-info-expression: '', debug-info-location: '' }
callSites: []
constants: []
machineFunctionInfo: {}
body: |
bb.0.entry:
successors: %bb.1(0x40000000), %bb.2(0x40000000)
liveins: $r0, $r1, $r2, $r7, $lr
frame-setup tPUSH 14, $noreg, killed $r7, 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 $r7, -8
$lr = tMOVr $r2, 14, $noreg
tCMPi8 killed $r2, 3, 14, $noreg, implicit-def $cpsr
tBcc %bb.2, 3, killed $cpsr
bb.1.not.preheader:
successors: %bb.2(0x40000000), %bb.4(0x40000000)
liveins: $lr, $r0, $r1
$lr = t2WhileLoopStartLR killed renamable $lr, %bb.4, implicit-def dead $cpsr
tB %bb.2, 14, $noreg
bb.2.while.body.preheader:
successors: %bb.3(0x80000000)
liveins: $lr, $r0, $r1
renamable $r1, dead $cpsr = tSUBi8 killed renamable $r1, 2, 14, $noreg
renamable $r0, dead $cpsr = tSUBi8 killed renamable $r0, 2, 14, $noreg
bb.3.while.body:
successors: %bb.3(0x7c000000), %bb.4(0x04000000)
liveins: $lr, $r0, $r1
renamable $r2, renamable $r1 = t2LDRH_PRE killed renamable $r1, 2, 14, $noreg :: (load (s16) from %ir.scevgep4)
early-clobber renamable $r0 = t2STRH_PRE killed renamable $r2, killed renamable $r0, 2, 14, $noreg :: (store (s16) into %ir.scevgep7)
renamable $lr = t2LoopDec killed renamable $lr, 1
t2LoopEnd renamable $lr, %bb.3, implicit-def dead $cpsr
tB %bb.4, 14, $noreg
bb.4.while.end:
tPOP_RET 14, $noreg, def $r7, def $pc
...
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