dont-remove-loop-update3.mir
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# RUN: llc -mtriple=thumbv8.1m.main -mattr=+mve,+lob -run-pass=arm-low-overhead-loops --verify-machineinstrs %s -o - | FileCheck %s
# Local use after def, this mov is using r3:
#
# $r2 = tMOVr killed $r3, 14, $noreg
#
# We should optimise away the SUB
# CHECK: bb.1.vector.body:
# CHECK: renamable $r3, dead $cpsr = tSUBi8 killed renamable $r3, 4, 14, $noreg
# CHECK: $lr = MVE_LETP renamable $lr, %bb.1
--- |
target datalayout = "e-m:e-p:32:32-Fi8-i64:64-v128:64:128-a:0:32-n32-S64"
target triple = "thumbv8.1m.main-arm-unknown-eabi"
define dso_local void @local_use_after_def(i32* noalias nocapture %A, i32* noalias nocapture readonly %B, i32* noalias nocapture readonly %C, i32 %N) local_unnamed_addr #0 {
entry:
%cmp8 = icmp sgt i32 %N, 0
%0 = add i32 %N, 3
%1 = lshr i32 %0, 2
%2 = shl nuw i32 %1, 2
%3 = add i32 %2, -4
%4 = lshr i32 %3, 2
%5 = add nuw nsw i32 %4, 1
br i1 %cmp8, label %vector.ph, label %for.cond.cleanup
vector.ph: ; preds = %entry
call void @llvm.set.loop.iterations.i32(i32 %5)
br label %vector.body
vector.body: ; preds = %vector.body, %vector.ph
%lsr.iv17 = phi i32* [ %scevgep18, %vector.body ], [ %A, %vector.ph ]
%lsr.iv14 = phi i32* [ %scevgep15, %vector.body ], [ %C, %vector.ph ]
%lsr.iv = phi i32* [ %scevgep, %vector.body ], [ %B, %vector.ph ]
%6 = phi i32 [ %5, %vector.ph ], [ %11, %vector.body ]
%7 = phi i32 [ %N, %vector.ph ], [ %9, %vector.body ]
%lsr.iv13 = bitcast i32* %lsr.iv to <4 x i32>*
%lsr.iv1416 = bitcast i32* %lsr.iv14 to <4 x i32>*
%lsr.iv1719 = bitcast i32* %lsr.iv17 to <4 x i32>*
%8 = call <4 x i1> @llvm.arm.vctp32(i32 %7)
%9 = sub i32 %7, 4
%wide.masked.load = call <4 x i32> @llvm.masked.load.v4i32.p0v4i32(<4 x i32>* %lsr.iv13, i32 4, <4 x i1> %8, <4 x i32> undef), !tbaa !3
%wide.masked.load12 = call <4 x i32> @llvm.masked.load.v4i32.p0v4i32(<4 x i32>* %lsr.iv1416, i32 4, <4 x i1> %8, <4 x i32> undef), !tbaa !3
%10 = add nsw <4 x i32> %wide.masked.load12, %wide.masked.load
call void @llvm.masked.store.v4i32.p0v4i32(<4 x i32> %10, <4 x i32>* %lsr.iv1719, i32 4, <4 x i1> %8), !tbaa !3
%scevgep = getelementptr i32, i32* %lsr.iv, i32 4
%scevgep15 = getelementptr i32, i32* %lsr.iv14, i32 4
%scevgep18 = getelementptr i32, i32* %lsr.iv17, i32 4
%11 = call i32 @llvm.loop.decrement.reg.i32.i32.i32(i32 %6, i32 1)
%12 = icmp ne i32 %11, 0
br i1 %12, label %vector.body, label %for.cond.cleanup, !llvm.loop !7
for.cond.cleanup: ; preds = %vector.body, %entry
ret void
}
declare void @llvm.set.loop.iterations.i32(i32) #1
declare <4 x i1> @llvm.arm.vctp32(i32) #2
declare i32 @llvm.loop.decrement.reg.i32.i32.i32(i32, i32) #1
declare void @llvm.lifetime.start.p0i8(i64 immarg, i8* nocapture) #3
declare <4 x i32> @llvm.masked.load.v4i32.p0v4i32(<4 x i32>*, i32 immarg, <4 x i1>, <4 x i32>) #4
declare void @llvm.masked.store.v4i32.p0v4i32(<4 x i32>, <4 x i32>*, i32 immarg, <4 x i1>) #3
declare void @llvm.stackprotector(i8*, i8**) #5
attributes #0 = { nofree norecurse nounwind "correctly-rounded-divide-sqrt-fp-math"="false" "disable-tail-calls"="false" "frame-pointer"="all" "less-precise-fpmad"="false" "min-legal-vector-width"="0" "no-infs-fp-math"="true" "no-jump-tables"="false" "no-nans-fp-math"="true" "no-signed-zeros-fp-math"="true" "no-trapping-math"="true" "stack-protector-buffer-size"="8" "target-cpu"="generic" "target-features"="+armv8.1-m.main,+fp-armv8d16sp,+fp16,+fullfp16,+hwdiv,+lob,+mve.fp,+ras,+strict-align,+thumb-mode,+vfp2sp,+vfp3d16sp,+vfp4d16sp" "unsafe-fp-math"="true" "use-soft-float"="false" }
attributes #1 = { noduplicate nounwind }
attributes #2 = { nounwind readnone }
attributes #3 = { argmemonly nounwind willreturn }
attributes #4 = { argmemonly nounwind readonly willreturn }
attributes #5 = { nounwind }
!llvm.module.flags = !{!0, !1}
!llvm.ident = !{!2}
!0 = !{i32 1, !"wchar_size", i32 4}
!1 = !{i32 1, !"min_enum_size", i32 4}
!2 = !{!"clang version 10.0.0 (http://github.com/llvm/llvm-project 2589b6d9edda73280fe1dc1d944ee34e22fe9a6f)"}
!3 = !{!4, !4, i64 0}
!4 = !{!"int", !5, i64 0}
!5 = !{!"omnipotent char", !6, i64 0}
!6 = !{!"Simple C++ TBAA"}
!7 = distinct !{!7, !8}
!8 = !{!"llvm.loop.isvectorized", i32 1}
...
---
name: local_use_after_def
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: '' }
- { reg: '$r3', virtual-reg: '' }
frameInfo:
isFrameAddressTaken: false
isReturnAddressTaken: false
hasStackMap: false
hasPatchPoint: false
stackSize: 8
offsetAdjustment: 0
maxAlignment: 4
adjustsStack: false
hasCalls: false
stackProtector: ''
maxCallFrameSize: 0
cvBytesOfCalleeSavedRegisters: 0
hasOpaqueSPAdjustment: false
hasVAStart: false
hasMustTailInVarArgFunc: false
localFrameSize: 0
savePoint: ''
restorePoint: ''
fixedStack: []
stack:
- { id: 0, name: '', type: spill-slot, offset: -4, size: 4, alignment: 4,
stack-id: default, callee-saved-register: '$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(0x80000000)
liveins: $r0, $r1, $r2, $r3, $lr
frame-setup tPUSH 14, $noreg, $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
$r7 = frame-setup tMOVr $sp, 14, $noreg
frame-setup CFI_INSTRUCTION def_cfa_register $r7
tCMPi8 renamable $r3, 1, 14, $noreg, implicit-def $cpsr
t2IT 11, 8, implicit-def $itstate
tPOP_RET 11, killed $cpsr, def $r7, def $pc, implicit killed $itstate
renamable $r12 = t2ADDri renamable $r3, 3, 14, $noreg, $noreg
renamable $lr = t2MOVi 1, 14, $noreg, $noreg
renamable $r12 = t2BICri killed renamable $r12, 3, 14, $noreg, $noreg
renamable $r12 = t2SUBri killed renamable $r12, 4, 14, $noreg, $noreg
renamable $lr = nuw nsw t2ADDrs killed renamable $lr, killed renamable $r12, 19, 14, $noreg, $noreg
t2DoLoopStart renamable $lr
bb.1.vector.body:
successors: %bb.1(0x7c000000), %bb.2(0x04000000)
liveins: $lr, $r0, $r1, $r2, $r3
renamable $vpr = MVE_VCTP32 renamable $r3, 0, $noreg
MVE_VPST 4, implicit $vpr
renamable $r1, renamable $q0 = MVE_VLDRWU32_post killed renamable $r1, 16, 1, renamable $vpr :: (load 16 from %ir.lsr.iv13, align 4, !tbaa !3)
renamable $r2, renamable $q1 = MVE_VLDRWU32_post killed renamable $r2, 16, 1, renamable $vpr :: (load 16 from %ir.lsr.iv1416, align 4, !tbaa !3)
renamable $r3, dead $cpsr = tSUBi8 killed renamable $r3, 4, 14, $noreg
renamable $q0 = nsw MVE_VADDi32 killed renamable $q1, killed renamable $q0, 0, $noreg, undef renamable $q0
MVE_VPST 8, implicit $vpr
renamable $r0 = MVE_VSTRWU32_post killed renamable $q0, killed renamable $r0, 16, 1, killed renamable $vpr :: (store 16 into %ir.lsr.iv1719, align 4, !tbaa !3)
renamable $lr = t2LoopDec killed renamable $lr, 1
$r2 = tMOVr killed $r3, 14, $noreg
t2LoopEnd renamable $lr, %bb.1, implicit-def dead $cpsr
tB %bb.2, 14, $noreg
bb.2.for.cond.cleanup:
tPOP_RET 14, $noreg, def $r7, def $pc
...