; LLVM IR from sca-secure-library-sca25519/sca25519 :: libopencm3/lib/lpc43xx (uart)

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

; Function Attrs: nounwind uwtable
define dso_local zeroext i8 @uart_read(i32 noundef %0) #1 {
  %2 = alloca i32, align 4
  %3 = alloca i32, align 4
  %4 = alloca i8, align 1
  store i32 %0, ptr %2, align 4, !tbaa !5
  call void @llvm.lifetime.start.p0(i64 4, ptr %3) #2
  call void @llvm.lifetime.start.p0(i64 1, ptr %4) #2
  %5 = load i32, ptr %2, align 4, !tbaa !5
  store i32 %5, ptr %3, align 4, !tbaa !5
  br label %6

6:                                                ; preds = %14, %1
  %7 = load i32, ptr %3, align 4, !tbaa !5
  %8 = add i32 %7, 20
  %9 = zext i32 %8 to i64
  %10 = inttoptr i64 %9 to ptr
  %11 = load volatile i32, ptr %10, align 4, !tbaa !5
  %12 = and i32 %11, 1
  %13 = icmp eq i32 %12, 0
  br i1 %13, label %14, label %15

14:                                               ; preds = %6
  br label %6, !llvm.loop !9

15:                                               ; preds = %6
  %16 = load i32, ptr %3, align 4, !tbaa !5
  %17 = add i32 %16, 0
  %18 = zext i32 %17 to i64
  %19 = inttoptr i64 %18 to ptr
  %20 = load volatile i32, ptr %19, align 4, !tbaa !5
  %21 = and i32 %20, 255
  %22 = trunc i32 %21 to i8
  store i8 %22, ptr %4, align 1, !tbaa !11
  %23 = load i8, ptr %4, align 1, !tbaa !11
  call void @llvm.lifetime.end.p0(i64 1, ptr %4) #2
  call void @llvm.lifetime.end.p0(i64 4, ptr %3) #2
  ret i8 %23
}

attributes #0 = { nocallback nofree nosync nounwind willreturn memory(argmem: readwrite) }
attributes #1 = { 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 #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 = !{!"int", !7, i64 0}
!7 = !{!"omnipotent char", !8, i64 0}
!8 = !{!"Simple C/C++ TBAA"}
!9 = distinct !{!9, !10}
!10 = !{!"llvm.loop.mustprogress"}
!11 = !{!7, !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: nofree norecurse nounwind uwtable
define dso_local zeroext i8 @uart_read(i32 noundef %0) local_unnamed_addr #0 {
  %2 = add i32 %0, 20
  %3 = zext i32 %2 to i64
  %4 = inttoptr i64 %3 to ptr
  br label %5

5:                                                ; preds = %5, %1
  %6 = load volatile i32, ptr %4, align 4, !tbaa !5
  %7 = and i32 %6, 1
  %8 = icmp eq i32 %7, 0
  br i1 %8, label %5, label %9, !llvm.loop !9

9:                                                ; preds = %5
  %10 = zext i32 %0 to i64
  %11 = inttoptr i64 %10 to ptr
  %12 = load volatile i32, ptr %11, align 4, !tbaa !5
  %13 = trunc i32 %12 to i8
  ret i8 %13
}

attributes #0 = { nofree norecurse 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 = !{!"int", !7, i64 0}
!7 = !{!"omnipotent char", !8, i64 0}
!8 = !{!"Simple C/C++ TBAA"}
!9 = distinct !{!9, !10}
!10 = !{!"llvm.loop.mustprogress"}


; Effective O3 passes: EarlyCSEPass,GlobalOptPass,IPSCCPPass,InferFunctionAttrsPass,InstCombinePass,LICMPass,PostOrderFunctionAttrsPass,SROAPass,SimplifyCFGPass