; LLVM IR from thefatihcinar/strings-exercises :: Solutions/Converting Lowercase String to Uppercase (lowercase-string-to-uppercase)

; 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: nounwind uwtable
define dso_local void @ConvertLowercaseStringToUppercase(ptr noundef %0) #0 {
  %2 = alloca ptr, align 8
  %3 = alloca i32, align 4
  store ptr %0, ptr %2, align 8, !tbaa !5
  call void @llvm.lifetime.start.p0(i64 4, ptr %3) #2
  store i32 0, ptr %3, align 4, !tbaa !9
  br label %4

4:                                                ; preds = %33, %20, %1
  %5 = load ptr, ptr %2, align 8, !tbaa !5
  %6 = load i32, ptr %3, align 4, !tbaa !9
  %7 = sext i32 %6 to i64
  %8 = getelementptr inbounds i8, ptr %5, i64 %7
  %9 = load i8, ptr %8, align 1, !tbaa !11
  %10 = sext i8 %9 to i32
  %11 = icmp ne i32 %10, 0
  br i1 %11, label %12, label %36

12:                                               ; preds = %4
  %13 = load ptr, ptr %2, align 8, !tbaa !5
  %14 = load i32, ptr %3, align 4, !tbaa !9
  %15 = sext i32 %14 to i64
  %16 = getelementptr inbounds i8, ptr %13, i64 %15
  %17 = load i8, ptr %16, align 1, !tbaa !11
  %18 = call i32 @IsLowercase(i8 noundef signext %17)
  %19 = icmp ne i32 %18, 0
  br i1 %19, label %20, label %33

20:                                               ; preds = %12
  %21 = load ptr, ptr %2, align 8, !tbaa !5
  %22 = load i32, ptr %3, align 4, !tbaa !9
  %23 = sext i32 %22 to i64
  %24 = getelementptr inbounds i8, ptr %21, i64 %23
  %25 = load i8, ptr %24, align 1, !tbaa !11
  %26 = call signext i8 @LowerToUpper(i8 noundef signext %25)
  %27 = load ptr, ptr %2, align 8, !tbaa !5
  %28 = load i32, ptr %3, align 4, !tbaa !9
  %29 = sext i32 %28 to i64
  %30 = getelementptr inbounds i8, ptr %27, i64 %29
  store i8 %26, ptr %30, align 1, !tbaa !11
  %31 = load i32, ptr %3, align 4, !tbaa !9
  %32 = add nsw i32 %31, 1
  store i32 %32, ptr %3, align 4, !tbaa !9
  br label %4, !llvm.loop !12

33:                                               ; preds = %12
  %34 = load i32, ptr %3, align 4, !tbaa !9
  %35 = add nsw i32 %34, 1
  store i32 %35, ptr %3, align 4, !tbaa !9
  br label %4, !llvm.loop !12

36:                                               ; preds = %4
  call void @llvm.lifetime.end.p0(i64 4, ptr %3) #2
  ret void
}

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

; Function Attrs: nounwind uwtable
declare dso_local i32 @IsLowercase(i8 noundef signext) #0

; Function Attrs: nounwind uwtable
declare dso_local signext i8 @LowerToUpper(i8 noundef signext) #0

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

attributes #0 = { 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 = { nocallback nofree nosync nounwind willreturn memory(argmem: readwrite) }
attributes #2 = { 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/C++ TBAA"}
!9 = !{!10, !10, i64 0}
!10 = !{!"int", !7, i64 0}
!11 = !{!7, !7, i64 0}
!12 = distinct !{!12, !13}
!13 = !{!"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: nounwind uwtable
define dso_local void @ConvertLowercaseStringToUppercase(ptr nocapture noundef %0) local_unnamed_addr #0 {
  %2 = load i8, ptr %0, align 1, !tbaa !5
  %.not10 = icmp eq i8 %2, 0
  br i1 %.not10, label %._crit_edge, label %.lr.ph

.lr.ph:                                           ; preds = %1, %.backedge
  %indvars.iv = phi i64 [ %indvars.iv.next, %.backedge ], [ 0, %1 ]
  %3 = phi i8 [ %10, %.backedge ], [ %2, %1 ]
  %4 = tail call i32 @IsLowercase(i8 noundef signext %3)
  %.not9 = icmp eq i32 %4, 0
  br i1 %.not9, label %.backedge, label %5

5:                                                ; preds = %.lr.ph
  %6 = getelementptr inbounds i8, ptr %0, i64 %indvars.iv
  %7 = load i8, ptr %6, align 1, !tbaa !5
  %8 = tail call signext i8 @LowerToUpper(i8 noundef signext %7)
  store i8 %8, ptr %6, align 1, !tbaa !5
  br label %.backedge

.backedge:                                        ; preds = %.lr.ph, %5
  %indvars.iv.next = add nuw nsw i64 %indvars.iv, 1
  %9 = getelementptr inbounds i8, ptr %0, i64 %indvars.iv.next
  %10 = load i8, ptr %9, align 1, !tbaa !5
  %.not = icmp eq i8 %10, 0
  br i1 %.not, label %._crit_edge, label %.lr.ph, !llvm.loop !8

._crit_edge:                                      ; preds = %.backedge, %1
  ret void
}

; Function Attrs: nounwind uwtable
declare dso_local i32 @IsLowercase(i8 noundef signext) local_unnamed_addr #0

; Function Attrs: nounwind uwtable
declare dso_local signext i8 @LowerToUpper(i8 noundef signext) local_unnamed_addr #0

attributes #0 = { 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 = !{!"omnipotent char", !7, i64 0}
!7 = !{!"Simple C/C++ TBAA"}
!8 = distinct !{!8, !9}
!9 = !{!"llvm.loop.mustprogress"}


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