id_result.copy_prop.ll

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

%"core::result::Result<u64, i64>" = type { i64, [0 x i64], [1 x i64] }

; Function Attrs: uwtable
define void @id_result(%"core::result::Result<u64, i64>"* noalias nocapture sret dereferenceable(16), %"core::result::Result<u64, i64>"* noalias nocapture dereferenceable(16)) unnamed_addr #0 {
entry-block:
  br label %start

start:                                            ; preds = %entry-block
  %2 = getelementptr inbounds %"core::result::Result<u64, i64>", %"core::result::Result<u64, i64>"* %1, i32 0, i32 0
  %3 = load i64, i64* %2, !range !0
  switch i64 %3, label %unreachable [
    i64 0, label %bb1
    i64 1, label %bb2
  ]

bb1:                                              ; preds = %start
  %4 = bitcast %"core::result::Result<u64, i64>"* %1 to { i64, i64 }*
  %5 = getelementptr inbounds { i64, i64 }, { i64, i64 }* %4, i32 0, i32 1
  %6 = load i64, i64* %5
  %7 = getelementptr inbounds %"core::result::Result<u64, i64>", %"core::result::Result<u64, i64>"* %0, i32 0, i32 0
  store i64 0, i64* %7
  %8 = bitcast %"core::result::Result<u64, i64>"* %0 to { i64, i64 }*
  %9 = getelementptr inbounds { i64, i64 }, { i64, i64 }* %8, i32 0, i32 1
  store i64 %6, i64* %9
  br label %bb3

bb2:                                              ; preds = %start
  %10 = bitcast %"core::result::Result<u64, i64>"* %1 to { i64, i64 }*
  %11 = getelementptr inbounds { i64, i64 }, { i64, i64 }* %10, i32 0, i32 1
  %12 = load i64, i64* %11
  %13 = getelementptr inbounds %"core::result::Result<u64, i64>", %"core::result::Result<u64, i64>"* %0, i32 0, i32 0
  store i64 1, i64* %13
  %14 = bitcast %"core::result::Result<u64, i64>"* %0 to { i64, i64 }*
  %15 = getelementptr inbounds { i64, i64 }, { i64, i64 }* %14, i32 0, i32 1
  store i64 %12, i64* %15
  br label %bb3

bb3:                                              ; preds = %bb1, %bb2
  ret void

unreachable:                                      ; preds = %start
  unreachable
}

attributes #0 = { uwtable }

!0 = !{i64 0, i64 2}

id_result.no_copy_prop.ll

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

%"core::result::Result<u64, i64>" = type { i64, [0 x i64], [1 x i64] }

; Function Attrs: uwtable
define void @id_result(%"core::result::Result<u64, i64>"* noalias nocapture sret dereferenceable(16), %"core::result::Result<u64, i64>"* noalias nocapture dereferenceable(16)) unnamed_addr #0 {
entry-block:
  br label %start

start:                                            ; preds = %entry-block
  %2 = getelementptr inbounds %"core::result::Result<u64, i64>", %"core::result::Result<u64, i64>"* %1, i32 0, i32 0
  %3 = load i64, i64* %2, !range !0
  switch i64 %3, label %unreachable [
    i64 0, label %bb1
    i64 1, label %bb2
  ]

bb1:                                              ; preds = %start
  %4 = bitcast %"core::result::Result<u64, i64>"* %1 to { i64, i64 }*
  %5 = getelementptr inbounds { i64, i64 }, { i64, i64 }* %4, i32 0, i32 1
  %6 = load i64, i64* %5
  %7 = getelementptr inbounds %"core::result::Result<u64, i64>", %"core::result::Result<u64, i64>"* %0, i32 0, i32 0
  store i64 0, i64* %7
  %8 = bitcast %"core::result::Result<u64, i64>"* %0 to { i64, i64 }*
  %9 = getelementptr inbounds { i64, i64 }, { i64, i64 }* %8, i32 0, i32 1
  store i64 %6, i64* %9
  br label %bb3

bb2:                                              ; preds = %start
  %10 = bitcast %"core::result::Result<u64, i64>"* %1 to { i64, i64 }*
  %11 = getelementptr inbounds { i64, i64 }, { i64, i64 }* %10, i32 0, i32 1
  %12 = load i64, i64* %11
  %13 = getelementptr inbounds %"core::result::Result<u64, i64>", %"core::result::Result<u64, i64>"* %0, i32 0, i32 0
  store i64 1, i64* %13
  %14 = bitcast %"core::result::Result<u64, i64>"* %0 to { i64, i64 }*
  %15 = getelementptr inbounds { i64, i64 }, { i64, i64 }* %14, i32 0, i32 1
  store i64 %12, i64* %15
  br label %bb3

bb3:                                              ; preds = %bb1, %bb2
  ret void

unreachable:                                      ; preds = %start
  unreachable
}

attributes #0 = { uwtable }

!0 = !{i64 0, i64 2}

id_result.rs

#![crate_type="lib"]

#[no_mangle]
pub fn id_result(a: Result<u64, i64>) -> Result<u64, i64> {
    match a {
        Ok(x) => Ok(x),
        Err(y) => Err(y),
    }
}