; LLVM IR from shamadee/web-dsp-demo :: cpp/dft.ll (ZN16FourierTransform8findPeakEPdi)

; Unoptimized IR (clang -disable-llvm-passes):
target datalayout = "e-m:e-p270:32:32-p271:32:32-p272:64:64-i64:64-i128:128-f80:128-n8:16:32:64-S128"
target triple = "x86_64-unknown-linux-gnu"

; Function Attrs: mustprogress uwtable
define dso_local noundef double @_ZN16FourierTransform8findPeakEPdi(ptr noundef nonnull align 8 dereferenceable(80) %0, ptr noundef %1, i32 noundef %2) #0 align 2 {
  %4 = alloca ptr, align 8
  %5 = alloca ptr, align 8
  %6 = alloca i32, align 4
  %7 = alloca double, align 8
  %8 = alloca i32, align 4
  store ptr %0, ptr %4, align 8, !tbaa !5
  store ptr %1, ptr %5, align 8, !tbaa !5
  store i32 %2, ptr %6, align 4, !tbaa !9
  %9 = load ptr, ptr %4, align 8
  call void @llvm.lifetime.start.p0(i64 8, ptr %7) #3
  store double 0.000000e+00, ptr %7, align 8, !tbaa !11
  call void @llvm.lifetime.start.p0(i64 4, ptr %8) #3
  store i32 0, ptr %8, align 4, !tbaa !9
  br label %10

10:                                               ; preds = %35, %3
  %11 = load i32, ptr %8, align 4, !tbaa !9
  %12 = load i32, ptr %6, align 4, !tbaa !9
  %13 = icmp slt i32 %11, %12
  br i1 %13, label %15, label %14

14:                                               ; preds = %10
  call void @llvm.lifetime.end.p0(i64 4, ptr %8) #3
  br label %38

15:                                               ; preds = %10
  %16 = load ptr, ptr %5, align 8, !tbaa !5
  %17 = load i32, ptr %8, align 4, !tbaa !9
  %18 = sext i32 %17 to i64
  %19 = getelementptr inbounds double, ptr %16, i64 %18
  %20 = load double, ptr %19, align 8, !tbaa !11
  %21 = call noundef double @_ZSt3absd(double noundef %20)
  %22 = load double, ptr %7, align 8, !tbaa !11
  %23 = fcmp ogt double %21, %22
  br i1 %23, label %24, label %31

24:                                               ; preds = %15
  %25 = load ptr, ptr %5, align 8, !tbaa !5
  %26 = load i32, ptr %8, align 4, !tbaa !9
  %27 = sext i32 %26 to i64
  %28 = getelementptr inbounds double, ptr %25, i64 %27
  %29 = load double, ptr %28, align 8, !tbaa !11
  %30 = call noundef double @_ZSt3absd(double noundef %29)
  br label %33

31:                                               ; preds = %15
  %32 = load double, ptr %7, align 8, !tbaa !11
  br label %33

33:                                               ; preds = %31, %24
  %34 = phi double [ %30, %24 ], [ %32, %31 ]
  store double %34, ptr %7, align 8, !tbaa !11
  br label %35

35:                                               ; preds = %33
  %36 = load i32, ptr %8, align 4, !tbaa !9
  %37 = add nsw i32 %36, 1
  store i32 %37, ptr %8, align 4, !tbaa !9
  br label %10, !llvm.loop !13

38:                                               ; preds = %14
  %39 = load double, ptr %7, align 8, !tbaa !11
  call void @llvm.lifetime.end.p0(i64 8, ptr %7) #3
  ret double %39
}

; Function Attrs: nocallback nofree nosync nounwind willreturn memory(argmem: readwrite)
declare void @llvm.lifetime.start.p0(i64 immarg, ptr nocapture) #1

; Function Attrs: inlinehint mustprogress nounwind uwtable
declare dso_local noundef double @_ZSt3absd(double noundef) #2

; Function Attrs: nocallback nofree nosync nounwind willreturn memory(argmem: readwrite)
declare void @llvm.lifetime.end.p0(i64 immarg, ptr nocapture) #1

attributes #0 = { mustprogress uwtable "min-legal-vector-width"="0" "no-trapping-math"="true" "stack-protector-buffer-size"="8" "target-cpu"="x86-64" "target-features"="+cmov,+cx8,+fxsr,+mmx,+sse,+sse2,+x87" "tune-cpu"="generic" }
attributes #1 = { nocallback nofree nosync nounwind willreturn memory(argmem: readwrite) }
attributes #2 = { inlinehint mustprogress nounwind uwtable "min-legal-vector-width"="0" "no-trapping-math"="true" "stack-protector-buffer-size"="8" "target-cpu"="x86-64" "target-features"="+cmov,+cx8,+fxsr,+mmx,+sse,+sse2,+x87" "tune-cpu"="generic" }
attributes #3 = { nounwind }

!llvm.module.flags = !{!0, !1, !2, !3}
!llvm.ident = !{!4}

!0 = !{i32 1, !"wchar_size", i32 4}
!1 = !{i32 8, !"PIC Level", i32 2}
!2 = !{i32 7, !"PIE Level", i32 2}
!3 = !{i32 7, !"uwtable", i32 2}
!4 = !{!"clang version 19.1.0 (git@github.com:llvm/llvm-project.git a4bf6cd7cfb1a1421ba92bca9d017b49936c55e4)"}
!5 = !{!6, !6, i64 0}
!6 = !{!"any pointer", !7, i64 0}
!7 = !{!"omnipotent char", !8, i64 0}
!8 = !{!"Simple C++ TBAA"}
!9 = !{!10, !10, i64 0}
!10 = !{!"int", !7, i64 0}
!11 = !{!12, !12, i64 0}
!12 = !{!"double", !7, i64 0}
!13 = distinct !{!13, !14}
!14 = !{!"llvm.loop.mustprogress"}


; Optimized IR (opt -passes='default<O3>'):
target datalayout = "e-m:e-p270:32:32-p271:32:32-p272:64:64-i64:64-i128:128-f80:128-n8:16:32:64-S128"
target triple = "x86_64-unknown-linux-gnu"

; Function Attrs: mustprogress nounwind uwtable
define dso_local noundef double @_ZN16FourierTransform8findPeakEPdi(ptr nocapture noundef nonnull readnone align 8 dereferenceable(80) %0, ptr nocapture noundef readonly %1, i32 noundef %2) local_unnamed_addr #0 align 2 {
  %4 = icmp sgt i32 %2, 0
  br i1 %4, label %.lr.ph.preheader, label %._crit_edge

.lr.ph.preheader:                                 ; preds = %3
  %wide.trip.count = zext nneg i32 %2 to i64
  br label %.lr.ph

._crit_edge:                                      ; preds = %12, %3
  %.010.lcssa = phi double [ 0.000000e+00, %3 ], [ %13, %12 ]
  ret double %.010.lcssa

.lr.ph:                                           ; preds = %.lr.ph.preheader, %12
  %indvars.iv = phi i64 [ 0, %.lr.ph.preheader ], [ %indvars.iv.next, %12 ]
  %.01011 = phi double [ 0.000000e+00, %.lr.ph.preheader ], [ %13, %12 ]
  %5 = getelementptr inbounds double, ptr %1, i64 %indvars.iv
  %6 = load double, ptr %5, align 8, !tbaa !5
  %7 = tail call noundef double @_ZSt3absd(double noundef %6)
  %8 = fcmp ogt double %7, %.01011
  br i1 %8, label %9, label %12

9:                                                ; preds = %.lr.ph
  %10 = load double, ptr %5, align 8, !tbaa !5
  %11 = tail call noundef double @_ZSt3absd(double noundef %10)
  br label %12

12:                                               ; preds = %.lr.ph, %9
  %13 = phi double [ %11, %9 ], [ %.01011, %.lr.ph ]
  %indvars.iv.next = add nuw nsw i64 %indvars.iv, 1
  %exitcond.not = icmp eq i64 %indvars.iv.next, %wide.trip.count
  br i1 %exitcond.not, label %._crit_edge, label %.lr.ph, !llvm.loop !9
}

; Function Attrs: inlinehint mustprogress nounwind uwtable
declare dso_local noundef double @_ZSt3absd(double noundef) local_unnamed_addr #1

attributes #0 = { mustprogress nounwind uwtable "min-legal-vector-width"="0" "no-trapping-math"="true" "stack-protector-buffer-size"="8" "target-cpu"="x86-64" "target-features"="+cmov,+cx8,+fxsr,+mmx,+sse,+sse2,+x87" "tune-cpu"="generic" }
attributes #1 = { inlinehint mustprogress nounwind uwtable "min-legal-vector-width"="0" "no-trapping-math"="true" "stack-protector-buffer-size"="8" "target-cpu"="x86-64" "target-features"="+cmov,+cx8,+fxsr,+mmx,+sse,+sse2,+x87" "tune-cpu"="generic" }

!llvm.module.flags = !{!0, !1, !2, !3}
!llvm.ident = !{!4}

!0 = !{i32 1, !"wchar_size", i32 4}
!1 = !{i32 8, !"PIC Level", i32 2}
!2 = !{i32 7, !"PIE Level", i32 2}
!3 = !{i32 7, !"uwtable", i32 2}
!4 = !{!"clang version 19.1.0 (git@github.com:llvm/llvm-project.git a4bf6cd7cfb1a1421ba92bca9d017b49936c55e4)"}
!5 = !{!6, !6, i64 0}
!6 = !{!"double", !7, i64 0}
!7 = !{!"omnipotent char", !8, i64 0}
!8 = !{!"Simple C++ TBAA"}
!9 = distinct !{!9, !10}
!10 = !{!"llvm.loop.mustprogress"}


; Effective O3 passes: EarlyCSEPass,GVNPass,GlobalOptPass,IndVarSimplifyPass,InferFunctionAttrsPass,InstCombinePass,InstSimplifyPass,JumpThreadingPass,LCSSAPass,LoopRotatePass,LoopSimplifyPass,LoopUnrollPass,PostOrderFunctionAttrsPass,SROAPass,SimplifyCFGPass,TailCallElimPass