; LLVM IR from google/esh :: examples/emulation/armv8M-32/platform/uart (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"

%struct.UART_TypeDef = type { i64, i64, i64, i64, i64 }

; Function Attrs: nounwind uwtable
define dso_local i32 @ugetc() #0 {
  br label %1

1:                                                ; preds = %6, %0
  %2 = load volatile i64, ptr getelementptr inbounds (%struct.UART_TypeDef, ptr inttoptr (i64 1362112512 to ptr), i32 0, i32 1), align 8, !tbaa !5
  %3 = and i64 %2, 2
  %4 = icmp ne i64 %3, 0
  %5 = xor i1 %4, true
  br i1 %5, label %6, label %7

6:                                                ; preds = %1
  br label %1, !llvm.loop !10

7:                                                ; preds = %1
  %8 = load volatile i64, ptr inttoptr (i64 1362112512 to ptr), align 8, !tbaa !12
  %9 = trunc i64 %8 to i32
  ret i32 %9
}

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, !7, i64 8}
!6 = !{!"", !7, i64 0, !7, i64 8, !7, i64 16, !7, i64 24, !7, i64 32}
!7 = !{!"long", !8, i64 0}
!8 = !{!"omnipotent char", !9, i64 0}
!9 = !{!"Simple C/C++ TBAA"}
!10 = distinct !{!10, !11}
!11 = !{!"llvm.loop.mustprogress"}
!12 = !{!6, !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 i32 @ugetc() local_unnamed_addr #0 {
  br label %1

1:                                                ; preds = %1, %0
  %2 = load volatile i64, ptr inttoptr (i64 1362112520 to ptr), align 8, !tbaa !5
  %3 = and i64 %2, 2
  %.not = icmp eq i64 %3, 0
  br i1 %.not, label %1, label %4, !llvm.loop !10

4:                                                ; preds = %1
  %5 = load volatile i64, ptr inttoptr (i64 1362112512 to ptr), align 4096, !tbaa !12
  %6 = trunc i64 %5 to i32
  ret i32 %6
}

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, !7, i64 8}
!6 = !{!"", !7, i64 0, !7, i64 8, !7, i64 16, !7, i64 24, !7, i64 32}
!7 = !{!"long", !8, i64 0}
!8 = !{!"omnipotent char", !9, i64 0}
!9 = !{!"Simple C/C++ TBAA"}
!10 = distinct !{!10, !11}
!11 = !{!"llvm.loop.mustprogress"}
!12 = !{!6, !7, i64 0}


; Effective O3 passes: GlobalOptPass,InferAlignmentPass,InstCombinePass,PostOrderFunctionAttrsPass,SimplifyCFGPass