; LLVM IR from AllenDowney/ExercisesInC :: examples (palindrome)

; 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: nocallback nofree nosync nounwind willreturn memory(argmem: readwrite)
declare void @llvm.lifetime.start.p0(i64 immarg, ptr nocapture) #0

; Function Attrs: nounwind willreturn memory(read)
declare i64 @strlen(ptr noundef) #1

; Function Attrs: nounwind allocsize(0)
declare noalias ptr @malloc(i64 noundef) #2

; Function Attrs: nocallback nofree nosync nounwind willreturn memory(argmem: readwrite)
declare void @llvm.lifetime.end.p0(i64 immarg, ptr nocapture) #0

; Function Attrs: nounwind uwtable
declare dso_local void @inplace_reverse(ptr noundef) #3

; Function Attrs: nounwind
declare ptr @strcpy(ptr noundef, ptr noundef) #4

; Function Attrs: nounwind
declare ptr @strcat(ptr noundef, ptr noundef) #4

; Function Attrs: nounwind uwtable
define dso_local ptr @palindrome5(ptr noundef %0) #3 {
  %2 = alloca ptr, align 8
  %3 = alloca i32, align 4
  %4 = alloca ptr, align 8
  store ptr %0, ptr %2, align 8, !tbaa !5
  call void @llvm.lifetime.start.p0(i64 4, ptr %3) #5
  %5 = load ptr, ptr %2, align 8, !tbaa !5
  %6 = call i64 @strlen(ptr noundef %5) #6
  %7 = trunc i64 %6 to i32
  store i32 %7, ptr %3, align 4, !tbaa !9
  call void @llvm.lifetime.start.p0(i64 8, ptr %4) #5
  %8 = load i32, ptr %3, align 4, !tbaa !9
  %9 = mul nsw i32 2, %8
  %10 = add nsw i32 %9, 1
  %11 = sext i32 %10 to i64
  %12 = mul i64 %11, 1
  %13 = call noalias ptr @malloc(i64 noundef %12) #7
  store ptr %13, ptr %4, align 8, !tbaa !5
  %14 = load ptr, ptr %4, align 8, !tbaa !5
  %15 = load ptr, ptr %2, align 8, !tbaa !5
  %16 = call ptr @strcpy(ptr noundef %14, ptr noundef %15) #5
  %17 = load ptr, ptr %2, align 8, !tbaa !5
  call void @inplace_reverse(ptr noundef %17)
  %18 = load ptr, ptr %4, align 8, !tbaa !5
  %19 = load ptr, ptr %2, align 8, !tbaa !5
  %20 = call ptr @strcat(ptr noundef %18, ptr noundef %19) #5
  %21 = load ptr, ptr %4, align 8, !tbaa !5
  call void @llvm.lifetime.end.p0(i64 8, ptr %4) #5
  call void @llvm.lifetime.end.p0(i64 4, ptr %3) #5
  ret ptr %21
}

attributes #0 = { nocallback nofree nosync nounwind willreturn memory(argmem: readwrite) }
attributes #1 = { nounwind willreturn memory(read) "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 #2 = { nounwind allocsize(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 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 #4 = { nounwind "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 #5 = { nounwind }
attributes #6 = { nounwind willreturn memory(read) }
attributes #7 = { nounwind allocsize(0) }

!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}


; 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 nofree nounwind willreturn memory(argmem: read)
declare i64 @strlen(ptr nocapture noundef) local_unnamed_addr #0

; Function Attrs: mustprogress nofree nounwind willreturn allockind("alloc,uninitialized") allocsize(0) memory(inaccessiblemem: readwrite)
declare noalias noundef ptr @malloc(i64 noundef) local_unnamed_addr #1

; Function Attrs: nounwind uwtable
declare dso_local void @inplace_reverse(ptr noundef) local_unnamed_addr #2

; Function Attrs: mustprogress nofree nounwind willreturn memory(argmem: readwrite)
declare ptr @strcpy(ptr noalias noundef returned writeonly, ptr noalias nocapture noundef readonly) local_unnamed_addr #3

; Function Attrs: mustprogress nofree nounwind willreturn memory(argmem: readwrite)
declare ptr @strcat(ptr noalias noundef returned, ptr noalias nocapture noundef readonly) local_unnamed_addr #3

; Function Attrs: nounwind uwtable
define dso_local noundef ptr @palindrome5(ptr noundef %0) local_unnamed_addr #2 {
  %2 = tail call i64 @strlen(ptr noundef nonnull dereferenceable(1) %0) #4
  %3 = trunc i64 %2 to i32
  %4 = shl nsw i32 %3, 1
  %5 = or disjoint i32 %4, 1
  %6 = sext i32 %5 to i64
  %7 = tail call noalias ptr @malloc(i64 noundef %6) #5
  %8 = tail call ptr @strcpy(ptr noundef nonnull dereferenceable(1) %7, ptr noundef nonnull dereferenceable(1) %0) #6
  tail call void @inplace_reverse(ptr noundef %0)
  %9 = tail call ptr @strcat(ptr noundef nonnull dereferenceable(1) %7, ptr noundef nonnull dereferenceable(1) %0) #6
  ret ptr %7
}

attributes #0 = { mustprogress nofree nounwind willreturn memory(argmem: read) "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 = { mustprogress nofree nounwind willreturn allockind("alloc,uninitialized") allocsize(0) memory(inaccessiblemem: readwrite) "alloc-family"="malloc" "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 #2 = { 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 = { mustprogress nofree nounwind willreturn memory(argmem: readwrite) "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 #4 = { nounwind willreturn memory(read) }
attributes #5 = { nounwind allocsize(0) }
attributes #6 = { 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)"}


; Effective O3 passes: EarlyCSEPass,GlobalOptPass,InferFunctionAttrsPass,InstCombinePass,PostOrderFunctionAttrsPass,ReassociatePass,SROAPass,TailCallElimPass