chain-bool-split.ll

; ModuleID = 'chain_bool_split.cgu-0.rs'
source_filename = "chain_bool_split.cgu-0.rs"
target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
target triple = "x86_64-unknown-linux-gnu"

%"2.std::ops::Range<usize>" = type { i64, i64 }
%"8.unwind::libunwind::_Unwind_Exception" = type { i64, void (i32, %"8.unwind::libunwind::_Unwind_Exception"*)*, [6 x i64] }
%"8.unwind::libunwind::_Unwind_Context" = type {}

; Function Attrs: uwtable
define i64 @range_chain_default_fold(%"2.std::ops::Range<usize>"* noalias nocapture readonly dereferenceable(16), %"2.std::ops::Range<usize>"* noalias nocapture readonly dereferenceable(16), i64 (i64, i64)* nocapture) unnamed_addr #0 personality i32 (i32, i32, i64, %"8.unwind::libunwind::_Unwind_Exception"*, %"8.unwind::libunwind::_Unwind_Context"*)* @rust_eh_personality {
entry-block:
  %3 = getelementptr inbounds %"2.std::ops::Range<usize>", %"2.std::ops::Range<usize>"* %0, i64 0, i32 0
  %4 = getelementptr inbounds %"2.std::ops::Range<usize>", %"2.std::ops::Range<usize>"* %0, i64 0, i32 1
  %5 = load i64, i64* %3, align 8
  %6 = load i64, i64* %4, align 8
  %7 = getelementptr inbounds %"2.std::ops::Range<usize>", %"2.std::ops::Range<usize>"* %1, i64 0, i32 0
  %8 = getelementptr inbounds %"2.std::ops::Range<usize>", %"2.std::ops::Range<usize>"* %1, i64 0, i32 1
  %9 = load i64, i64* %7, align 8
  %10 = load i64, i64* %8, align 8
  %11 = icmp ult i64 %5, %6
  br i1 %11, label %bb6.preheader, label %bb1.outer28.preheader

bb6.preheader:                                    ; preds = %entry-block
  br label %bb6

bb1.outer28.preheader.loopexit:                   ; preds = %bb6
  br label %bb1.outer28.preheader

bb1.outer28.preheader:                            ; preds = %bb1.outer28.preheader.loopexit, %entry-block
  %accum.0.ph32.ph = phi i64 [ 0, %entry-block ], [ %15, %bb1.outer28.preheader.loopexit ]
  br label %bb1.outer28

bb1.outer28:                                      ; preds = %bb1.outer28.preheader, %bb10
  %b.sroa.0.0.ph29 = phi i64 [ %17, %bb10 ], [ %9, %bb1.outer28.preheader ]
  %accum.0.ph32 = phi i64 [ %18, %bb10 ], [ %accum.0.ph32.ph, %bb1.outer28.preheader ]
  %front_active.0.ph33 = phi i8 [ 0, %bb10 ], [ 1, %bb1.outer28.preheader ]
  br label %bb1

bb1:                                              ; preds = %bb1, %bb1.outer28
  %front_active.0 = phi i8 [ %front_active.0.ph33, %bb1.outer28 ], [ 0, %bb1 ]
  %12 = icmp eq i8 %front_active.0, 0
  br i1 %12, label %bb3, label %bb1

bb3:                                              ; preds = %bb1
  %13 = icmp ult i64 %b.sroa.0.0.ph29, %10
  br i1 %13, label %bb10, label %bb9

bb6:                                              ; preds = %bb6.preheader, %bb6
  %accum.0.ph51 = phi i64 [ %15, %bb6 ], [ 0, %bb6.preheader ]
  %a.sroa.0.0.ph50 = phi i64 [ %14, %bb6 ], [ %5, %bb6.preheader ]
  %14 = add i64 %a.sroa.0.0.ph50, 1
  %15 = tail call i64 %2(i64 %accum.0.ph51, i64 %a.sroa.0.0.ph50)
  %16 = icmp ult i64 %14, %6
  br i1 %16, label %bb6, label %bb1.outer28.preheader.loopexit

bb9:                                              ; preds = %bb3
  ret i64 %accum.0.ph32

bb10:                                             ; preds = %bb3
  %17 = add i64 %b.sroa.0.0.ph29, 1
  %18 = tail call i64 %2(i64 %accum.0.ph32, i64 %b.sroa.0.0.ph29)
  br label %bb1.outer28
}

; Function Attrs: nounwind
declare i32 @rust_eh_personality(i32, i32, i64, %"8.unwind::libunwind::_Unwind_Exception"*, %"8.unwind::libunwind::_Unwind_Context"*) unnamed_addr #1

attributes #0 = { uwtable }
attributes #1 = { nounwind }

chain-bool-split.rs

#![crate_type="lib"]

use std::ops::Range;

#[no_mangle]
pub fn range_chain_default_fold(a: Range<usize>, b: Range<usize>, f: fn(usize, usize) -> usize) -> usize {
    let mut accum = 0;
    let mut a = a;
    let mut b = b;
    let mut front_active = true;
    loop {
        if front_active {
            match a.next() {
                Some(elt) => {
                    accum = f(accum, elt);
                }
                None => {
                    front_active = false;
                    continue;
                }
            }
        } else {
            let value = b.next();
            match value {
                Some(elt) => accum = f(accum, elt),
                None => break,
            }
        };
    }
    accum
}