Add in-place optimization for array map

[JulianKnodt]

This adds an in-place optimization for array map when the input and output types are the same size. It's still a little awkward because transmute does not work between dependently sized types.

Tracking Issue: #75243

cc: @the8472

[rust-highfive]

r? @cramertj

(rust_highfive has picked a reviewer for you, use r? to override)

[the8472]

Since it effectively has two implementations now maybe the drop test should also be changed to exercise both code paths.

[JulianKnodt]

Ah yea I will add further tests once I actually check that it compiles

[crlf0710]

r? @scottmcm

[Dylan-DPC-zz]

r? @Amanieu

[scottmcm]

@JulianKnodt Sorry for forgetting this PR.

You might want to check out https://www.llvm.org/docs/CommandGuide/FileCheck.html#tutorial, as we use that for codegen tests.

Do you have an example of the IR emitted with and without this change? We could maybe help identify the core things that are worth checking. Looking at what it currently emits in https://rust.godbolt.org/z/ezfPxr, maybe you're trying to get rid of that 1000-item memcpy at the end? Or maybe the 1000-item alloca?

Though, looking at the LLVM signature of the API,

define void @array_inc([1000 x i8]* noalias nocapture sret dereferenceable(1000) %0, [1000 x i8]* noalias nocapture readonly dereferenceable(1000) %x) unnamed_addr #0 personality i32 (i32, i32, i64, %"unwind::libunwind::_Unwind_Exception"*, %"unwind::libunwind::_Unwind_Context"*)* @rust_eh_personality !dbg !6 {

I'm not sure that this in-place is actually a win, because at the llvm level it needs to be dst[i] = f(src[i]) anyway.

Makes me wonder if this just needs NRVO to be turned on, instead of actually needing code changes...

[JulianKnodt]

@scottmcm no worries, I've been busy with other things so I've not been working on this PR as hard as I should be. Thank you for the update, I didn't know exactly how to view the LLVM output(and also I'm not particularly familiar with LLVM), but I think the main component is just to remove the alloca, since it can just reuse the existing memory rather than allocate new components. I changed it from [u32;N] -> [f32;N] and saw the same alloca instruction. From a quick google search, it seems that NRVO would be useful regardless of this PR.

[Amanieu]

Have you verified that this in fact produces better assembly code in practice?

[JulianKnodt]

Hm? It appears that it compiles differently on CI as compared to my own machine as welll....

[crlf0710]

Triage: Seems CI is still red here. @JulianKnodt

[JulianKnodt]

Ah yea I think there was some issue I was having where locally my test outputs were passing but they didn't work on CI here, I can double check

[JulianKnodt]

Just pulling the latest seems to have fixed it,
altho I did remove some AVX2 features from the codegen test.

[scottmcm]

Good to hear the tests are passing in CI now!

Would you might uploading (gist or whatever) the .lls you're getting with and without this change locally from the codegen test? I feel like this could use some stricter CHECKs (like no-alloc checks of some sort) to confirm it's doing what's wanted -- at least it looks like the array_cast_to_u64 one would currently pass against the IR I get in playground, and it's not obvious to me why there should be a memcpy in either. I'd like to diff them and propose updates.

[JulianKnodt]

LLVM Output

; ModuleID = 'array_map.3a1fbbbh-cgu.0'
source_filename = "array_map.3a1fbbbh-cgu.0"
target datalayout = "e-m:e-p270:32:32-p271:32:32-p272:64:64-i64:64-f80:128-n8:16:32:64-S128"
target triple = "x86_64-unknown-linux-gnu"

%"std::iter::Map<std::array::IntoIter<u32, 4_usize>, [closure@/home/kadmin/projects/rust/src/test/codegen/array-map.rs:14:9: 14:21]>" = type { [0 x i8], %"[closure@/home/kadmin/projects/rust/src/test/codegen/array-map.rs:14:9: 14:21]", [0 x i8], %"std::array::IntoIter<u32, 4_usize>", [0 x i64] }
%"[closure@/home/kadmin/projects/rust/src/test/codegen/array-map.rs:14:9: 14:21]" = type {}
%"std::array::IntoIter<u32, 4_usize>" = type { [0 x i64], { i64, i64 }, [0 x i32], [4 x i32], [0 x i32] }
%"std::iter::Map<std::array::IntoIter<u32, 4_usize>, [closure@/home/kadmin/projects/rust/src/test/codegen/array-map.rs:25:9: 25:21]>" = type { [0 x i8], %"[closure@/home/kadmin/projects/rust/src/test/codegen/array-map.rs:25:9: 25:21]", [0 x i8], %"std::array::IntoIter<u32, 4_usize>", [0 x i64] }
%"[closure@/home/kadmin/projects/rust/src/test/codegen/array-map.rs:25:9: 25:21]" = type {}
%"unwind::libunwind::_Unwind_Exception" = type { [0 x i64], i64, [0 x i64], void (i32, %"unwind::libunwind::_Unwind_Exception"*)*, [0 x i64], [6 x i64], [0 x i64] }
%"unwind::libunwind::_Unwind_Context" = type { [0 x i8] }

; Function Attrs: nounwind nonlazybind uwtable
define i128 @array_cast_to_float(i128 %0) unnamed_addr #0 personality i32 (i32, i32, i64, %"unwind::libunwind::_Unwind_Exception"*, %"unwind::libunwind::_Unwind_Context"*)* @rust_eh_personality {
start:
  %tmp.i.i.i.i.i2.i.i.i.i = alloca i32, align 4
  %tmp.i.i.i.i.i.i.i.i.i = alloca i64, align 8
  %src.i.i.i.i.i.i = alloca i64, align 8
  %iter1.i.i = alloca %"std::iter::Map<std::array::IntoIter<u32, 4_usize>, [closure@/home/kadmin/projects/rust/src/test/codegen/array-map.rs:14:9: 14:21]>", align 16
  %tmp.i.i.i.i = alloca i128, align 8
  %array.i.i = alloca i128, align 8
  %1 = bitcast i128* %array.i.i to i8*
  call void @llvm.lifetime.start.p0i8(i64 16, i8* nonnull %1)
  store i128 %0, i128* %array.i.i, align 8, !noalias !2
  %2 = bitcast i128* %tmp.i.i.i.i to i8*
  call void @llvm.lifetime.start.p0i8(i64 16, i8* nonnull %2) #3, !noalias !5
  %_6.i.i.i.i.i.i = ptrtoint i128* %array.i.i to i64
  %_6.i2.i.i.i.i.i = ptrtoint i128* %tmp.i.i.i.i to i64
  %_13.i.i.i.i.i.i = icmp ult i128* %tmp.i.i.i.i, %array.i.i
  %3 = sub i64 %_6.i.i.i.i.i.i, %_6.i2.i.i.i.i.i
  %4 = sub i64 %_6.i2.i.i.i.i.i, %_6.i.i.i.i.i.i
  %diff.0.i.i.i.i.i.i = select i1 %_13.i.i.i.i.i.i, i64 %3, i64 %4
  %5 = icmp ugt i64 %diff.0.i.i.i.i.i.i, 15
  br i1 %5, label %bb3.i.i.i.lr.ph.i.i, label %bb16.i.i.i.i.i

bb16.i.i.i.i.i:                                   ; preds = %start
  call void @llvm.trap() #3, !noalias !2
  unreachable

bb3.i.i.i.lr.ph.i.i:                              ; preds = %start
  call void @llvm.memcpy.p0i8.p0i8.i64(i8* nonnull align 8 dereferenceable(16) %2, i8* nonnull align 8 dereferenceable(16) %1, i64 16, i1 false) #3, !noalias !2
  %_7.sroa.0.0.copyload.i.i.i.i = load i128, i128* %tmp.i.i.i.i, align 8, !noalias !5
  call void @llvm.lifetime.end.p0i8(i64 16, i8* nonnull %2) #3, !noalias !5
  call void @llvm.lifetime.end.p0i8(i64 16, i8* nonnull %1)
  %6 = getelementptr inbounds %"std::iter::Map<std::array::IntoIter<u32, 4_usize>, [closure@/home/kadmin/projects/rust/src/test/codegen/array-map.rs:14:9: 14:21]>", %"std::iter::Map<std::array::IntoIter<u32, 4_usize>, [closure@/home/kadmin/projects/rust/src/test/codegen/array-map.rs:14:9: 14:21]>"* %iter1.i.i, i64 0, i32 0, i64 0
  call void @llvm.lifetime.start.p0i8(i64 32, i8* nonnull %6), !noalias !8
  %_8.sroa.0.sroa.0.0._8.sroa.0.0..sroa_idx.sroa_cast.i = bitcast %"std::iter::Map<std::array::IntoIter<u32, 4_usize>, [closure@/home/kadmin/projects/rust/src/test/codegen/array-map.rs:14:9: 14:21]>"* %iter1.i.i to i64*
  %7 = bitcast %"std::iter::Map<std::array::IntoIter<u32, 4_usize>, [closure@/home/kadmin/projects/rust/src/test/codegen/array-map.rs:14:9: 14:21]>"* %iter1.i.i to <2 x i64>*
  store <2 x i64> <i64 0, i64 4>, <2 x i64>* %7, align 16
  %_8.sroa.0.sroa.5.0._8.sroa.0.0..sroa_idx.sroa_idx.i = getelementptr inbounds %"std::iter::Map<std::array::IntoIter<u32, 4_usize>, [closure@/home/kadmin/projects/rust/src/test/codegen/array-map.rs:14:9: 14:21]>", %"std::iter::Map<std::array::IntoIter<u32, 4_usize>, [closure@/home/kadmin/projects/rust/src/test/codegen/array-map.rs:14:9: 14:21]>"* %iter1.i.i, i64 0, i32 3, i32 3
  %_8.sroa.0.sroa.5.0._8.sroa.0.0..sroa_idx.sroa_cast.i = bitcast [4 x i32]* %_8.sroa.0.sroa.5.0._8.sroa.0.0..sroa_idx.sroa_idx.i to i128*
  store i128 %_7.sroa.0.0.copyload.i.i.i.i, i128* %_8.sroa.0.sroa.5.0._8.sroa.0.0..sroa_idx.sroa_cast.i, align 16
  %8 = bitcast i64* %src.i.i.i.i.i.i to i8*
  %_6.i.i.i.i.i.i.i.i.i.i.i = ptrtoint %"std::iter::Map<std::array::IntoIter<u32, 4_usize>, [closure@/home/kadmin/projects/rust/src/test/codegen/array-map.rs:14:9: 14:21]>"* %iter1.i.i to i64
  %_6.i2.i.i.i.i.i.i.i.i.i.i = ptrtoint i64* %tmp.i.i.i.i.i.i.i.i.i to i64
  %_13.i.i.i.i.i.i.i.i.i.i.i = icmp ult i64* %tmp.i.i.i.i.i.i.i.i.i, %_8.sroa.0.sroa.0.0._8.sroa.0.0..sroa_idx.sroa_cast.i
  %9 = sub i64 %_6.i.i.i.i.i.i.i.i.i.i.i, %_6.i2.i.i.i.i.i.i.i.i.i.i
  %10 = sub i64 %_6.i2.i.i.i.i.i.i.i.i.i.i, %_6.i.i.i.i.i.i.i.i.i.i.i
  %diff.0.i.i.i.i.i.i.i.i.i.i.i = select i1 %_13.i.i.i.i.i.i.i.i.i.i.i, i64 %9, i64 %10
  %.not.i.i.i.i.i.i.i = icmp eq i64 %diff.0.i.i.i.i.i.i.i.i.i.i.i, 0
  %_6.i.i4.i.i.i.i.i.i.i.i = ptrtoint i64* %src.i.i.i.i.i.i to i64
  %11 = bitcast i32* %tmp.i.i.i.i.i2.i.i.i.i to i8*
  %_6.i2.i.i.i.i.i.i4.i.i.i.i = ptrtoint i32* %tmp.i.i.i.i.i2.i.i.i.i to i64
  br i1 %.not.i.i.i.i.i.i.i, label %bb3.i.i.i.us.i.i, label %bb3.i.i.i.lr.ph.split.i.i

bb3.i.i.i.us.i.i:                                 ; preds = %bb3.i.i.i.lr.ph.i.i
  %12 = bitcast i64* %tmp.i.i.i.i.i.i.i.i.i to i8*
  call void @llvm.lifetime.start.p0i8(i64 8, i8* nonnull %8) #3, !noalias !8
  store i64 1, i64* %src.i.i.i.i.i.i, align 8, !noalias !8
  call void @llvm.lifetime.start.p0i8(i64 8, i8* nonnull %12) #3, !noalias !8
  call void @llvm.trap() #3, !noalias !8
  unreachable

bb3.i.i.i.lr.ph.split.i.i:                        ; preds = %bb3.i.i.i.lr.ph.i.i
  %_13.i.i.i.i.i.i.i.i.i.i = icmp ugt i64* %src.i.i.i.i.i.i, %_8.sroa.0.sroa.0.0._8.sroa.0.0..sroa_idx.sroa_cast.i
  %13 = sub i64 %_6.i.i4.i.i.i.i.i.i.i.i, %_6.i.i.i.i.i.i.i.i.i.i.i
  %14 = sub i64 %_6.i.i.i.i.i.i.i.i.i.i.i, %_6.i.i4.i.i.i.i.i.i.i.i
  %diff.0.i.i.i.i.i.i.i.i.i.i = select i1 %_13.i.i.i.i.i.i.i.i.i.i, i64 %13, i64 %14
  %.not1.i.i.i.i.i.i.i = icmp eq i64 %diff.0.i.i.i.i.i.i.i.i.i.i, 0
  br i1 %.not1.i.i.i.i.i.i.i, label %bb3.i.i.i.us40.i.i, label %bb3.i.i.i.i.preheader.i

bb3.i.i.i.i.preheader.i:                          ; preds = %bb3.i.i.i.lr.ph.split.i.i
  %15 = getelementptr inbounds %"std::iter::Map<std::array::IntoIter<u32, 4_usize>, [closure@/home/kadmin/projects/rust/src/test/codegen/array-map.rs:14:9: 14:21]>", %"std::iter::Map<std::array::IntoIter<u32, 4_usize>, [closure@/home/kadmin/projects/rust/src/test/codegen/array-map.rs:14:9: 14:21]>"* %iter1.i.i, i64 0, i32 3, i32 3, i64 0
  call void @llvm.lifetime.start.p0i8(i64 4, i8* nonnull %11) #3, !noalias !11
  %_6.i.i.i.i.i.i.i3.i.i.i.i = ptrtoint i32* %15 to i64
  %_13.i.i.i.i.i.i.i5.i.i.i.i = icmp ult i32* %tmp.i.i.i.i.i2.i.i.i.i, %15
  %16 = sub i64 %_6.i.i.i.i.i.i.i3.i.i.i.i, %_6.i2.i.i.i.i.i.i4.i.i.i.i
  %17 = sub i64 %_6.i2.i.i.i.i.i.i4.i.i.i.i, %_6.i.i.i.i.i.i.i3.i.i.i.i
  %diff.0.i.i.i.i.i.i.i6.i.i.i.i = select i1 %_13.i.i.i.i.i.i.i5.i.i.i.i, i64 %16, i64 %17
  %.not.i.i.i7.i.i.i.i = icmp eq i64 %diff.0.i.i.i.i.i.i.i6.i.i.i.i, 0
  br i1 %.not.i.i.i7.i.i.i.i, label %bb16.i.i.i.i.i.i9.i.i.i.i, label %"_ZN4core5array40_$LT$impl$u20$$u5b$T$u3b$$u20$N$u5d$$GT$3map21MapGuard$LT$T$C$_$GT$4push17h4ac8fd7710fd6f9dE.exit.i.i"

bb3.i.i.i.us40.i.i:                               ; preds = %bb3.i.i.i.lr.ph.split.i.i
  call void @llvm.lifetime.start.p0i8(i64 8, i8* nonnull %8) #3, !noalias !8
  store i64 1, i64* %src.i.i.i.i.i.i, align 8, !noalias !8
  call void @llvm.trap() #3, !noalias !8
  unreachable

bb16.i.i.i.i.i.i9.i.i.i.i:                        ; preds = %"_ZN4core5array40_$LT$impl$u20$$u5b$T$u3b$$u20$N$u5d$$GT$3map21MapGuard$LT$T$C$_$GT$4push17h4ac8fd7710fd6f9dE.exit.i.2.i", %"_ZN4core5array40_$LT$impl$u20$$u5b$T$u3b$$u20$N$u5d$$GT$3map21MapGuard$LT$T$C$_$GT$4push17h4ac8fd7710fd6f9dE.exit.i.1.i", %"_ZN4core5array40_$LT$impl$u20$$u5b$T$u3b$$u20$N$u5d$$GT$3map21MapGuard$LT$T$C$_$GT$4push17h4ac8fd7710fd6f9dE.exit.i.i", %bb3.i.i.i.i.preheader.i
  %.lcssa.i = phi i64 [ 1, %bb3.i.i.i.i.preheader.i ], [ 2, %"_ZN4core5array40_$LT$impl$u20$$u5b$T$u3b$$u20$N$u5d$$GT$3map21MapGuard$LT$T$C$_$GT$4push17h4ac8fd7710fd6f9dE.exit.i.i" ], [ 3, %"_ZN4core5array40_$LT$impl$u20$$u5b$T$u3b$$u20$N$u5d$$GT$3map21MapGuard$LT$T$C$_$GT$4push17h4ac8fd7710fd6f9dE.exit.i.1.i" ], [ 4, %"_ZN4core5array40_$LT$impl$u20$$u5b$T$u3b$$u20$N$u5d$$GT$3map21MapGuard$LT$T$C$_$GT$4push17h4ac8fd7710fd6f9dE.exit.i.2.i" ]
  store i64 %.lcssa.i, i64* %_8.sroa.0.sroa.0.0._8.sroa.0.0..sroa_idx.sroa_cast.i, align 16, !noalias !8
  call void @llvm.trap() #3, !noalias !18
  unreachable

"_ZN4core5array40_$LT$impl$u20$$u5b$T$u3b$$u20$N$u5d$$GT$3map21MapGuard$LT$T$C$_$GT$4push17h4ac8fd7710fd6f9dE.exit.i.i": ; preds = %bb3.i.i.i.i.preheader.i
  call void @llvm.lifetime.end.p0i8(i64 4, i8* nonnull %11) #3, !noalias !11
  %18 = getelementptr inbounds %"std::iter::Map<std::array::IntoIter<u32, 4_usize>, [closure@/home/kadmin/projects/rust/src/test/codegen/array-map.rs:14:9: 14:21]>", %"std::iter::Map<std::array::IntoIter<u32, 4_usize>, [closure@/home/kadmin/projects/rust/src/test/codegen/array-map.rs:14:9: 14:21]>"* %iter1.i.i, i64 0, i32 3, i32 3, i64 1
  call void @llvm.lifetime.start.p0i8(i64 4, i8* nonnull %11) #3, !noalias !11
  %_6.i.i.i.i.i.i.i3.i.i.i.1.i = ptrtoint i32* %18 to i64
  %_13.i.i.i.i.i.i.i5.i.i.i.1.i = icmp ult i32* %tmp.i.i.i.i.i2.i.i.i.i, %18
  %19 = sub i64 %_6.i.i.i.i.i.i.i3.i.i.i.1.i, %_6.i2.i.i.i.i.i.i4.i.i.i.i
  %20 = sub i64 %_6.i2.i.i.i.i.i.i4.i.i.i.i, %_6.i.i.i.i.i.i.i3.i.i.i.1.i
  %diff.0.i.i.i.i.i.i.i6.i.i.i.1.i = select i1 %_13.i.i.i.i.i.i.i5.i.i.i.1.i, i64 %19, i64 %20
  %.not.i.i.i7.i.i.i.1.i = icmp eq i64 %diff.0.i.i.i.i.i.i.i6.i.i.i.1.i, 0
  br i1 %.not.i.i.i7.i.i.i.1.i, label %bb16.i.i.i.i.i.i9.i.i.i.i, label %"_ZN4core5array40_$LT$impl$u20$$u5b$T$u3b$$u20$N$u5d$$GT$3map21MapGuard$LT$T$C$_$GT$4push17h4ac8fd7710fd6f9dE.exit.i.1.i"

"_ZN4core5array40_$LT$impl$u20$$u5b$T$u3b$$u20$N$u5d$$GT$3map21MapGuard$LT$T$C$_$GT$4push17h4ac8fd7710fd6f9dE.exit.i.1.i": ; preds = %"_ZN4core5array40_$LT$impl$u20$$u5b$T$u3b$$u20$N$u5d$$GT$3map21MapGuard$LT$T$C$_$GT$4push17h4ac8fd7710fd6f9dE.exit.i.i"
  call void @llvm.lifetime.end.p0i8(i64 4, i8* nonnull %11) #3, !noalias !11
  %21 = getelementptr inbounds %"std::iter::Map<std::array::IntoIter<u32, 4_usize>, [closure@/home/kadmin/projects/rust/src/test/codegen/array-map.rs:14:9: 14:21]>", %"std::iter::Map<std::array::IntoIter<u32, 4_usize>, [closure@/home/kadmin/projects/rust/src/test/codegen/array-map.rs:14:9: 14:21]>"* %iter1.i.i, i64 0, i32 3, i32 3, i64 2
  call void @llvm.lifetime.start.p0i8(i64 4, i8* nonnull %11) #3, !noalias !11
  %_6.i.i.i.i.i.i.i3.i.i.i.2.i = ptrtoint i32* %21 to i64
  %_13.i.i.i.i.i.i.i5.i.i.i.2.i = icmp ult i32* %tmp.i.i.i.i.i2.i.i.i.i, %21
  %22 = sub i64 %_6.i.i.i.i.i.i.i3.i.i.i.2.i, %_6.i2.i.i.i.i.i.i4.i.i.i.i
  %23 = sub i64 %_6.i2.i.i.i.i.i.i4.i.i.i.i, %_6.i.i.i.i.i.i.i3.i.i.i.2.i
  %diff.0.i.i.i.i.i.i.i6.i.i.i.2.i = select i1 %_13.i.i.i.i.i.i.i5.i.i.i.2.i, i64 %22, i64 %23
  %.not.i.i.i7.i.i.i.2.i = icmp eq i64 %diff.0.i.i.i.i.i.i.i6.i.i.i.2.i, 0
  br i1 %.not.i.i.i7.i.i.i.2.i, label %bb16.i.i.i.i.i.i9.i.i.i.i, label %"_ZN4core5array40_$LT$impl$u20$$u5b$T$u3b$$u20$N$u5d$$GT$3map21MapGuard$LT$T$C$_$GT$4push17h4ac8fd7710fd6f9dE.exit.i.2.i"

"_ZN4core5array40_$LT$impl$u20$$u5b$T$u3b$$u20$N$u5d$$GT$3map21MapGuard$LT$T$C$_$GT$4push17h4ac8fd7710fd6f9dE.exit.i.2.i": ; preds = %"_ZN4core5array40_$LT$impl$u20$$u5b$T$u3b$$u20$N$u5d$$GT$3map21MapGuard$LT$T$C$_$GT$4push17h4ac8fd7710fd6f9dE.exit.i.1.i"
  call void @llvm.lifetime.end.p0i8(i64 4, i8* nonnull %11) #3, !noalias !11
  %24 = getelementptr inbounds %"std::iter::Map<std::array::IntoIter<u32, 4_usize>, [closure@/home/kadmin/projects/rust/src/test/codegen/array-map.rs:14:9: 14:21]>", %"std::iter::Map<std::array::IntoIter<u32, 4_usize>, [closure@/home/kadmin/projects/rust/src/test/codegen/array-map.rs:14:9: 14:21]>"* %iter1.i.i, i64 0, i32 3, i32 3, i64 3
  call void @llvm.lifetime.start.p0i8(i64 4, i8* nonnull %11) #3, !noalias !11
  %_6.i.i.i.i.i.i.i3.i.i.i.3.i = ptrtoint i32* %24 to i64
  %_13.i.i.i.i.i.i.i5.i.i.i.3.i = icmp ult i32* %tmp.i.i.i.i.i2.i.i.i.i, %24
  %25 = sub i64 %_6.i.i.i.i.i.i.i3.i.i.i.3.i, %_6.i2.i.i.i.i.i.i4.i.i.i.i
  %26 = sub i64 %_6.i2.i.i.i.i.i.i4.i.i.i.i, %_6.i.i.i.i.i.i.i3.i.i.i.3.i
  %diff.0.i.i.i.i.i.i.i6.i.i.i.3.i = select i1 %_13.i.i.i.i.i.i.i5.i.i.i.3.i, i64 %25, i64 %26
  %.not.i.i.i7.i.i.i.3.i = icmp eq i64 %diff.0.i.i.i.i.i.i.i6.i.i.i.3.i, 0
  br i1 %.not.i.i.i7.i.i.i.3.i, label %bb16.i.i.i.i.i.i9.i.i.i.i, label %"_ZN4core5array40_$LT$impl$u20$$u5b$T$u3b$$u20$N$u5d$$GT$3map17hdb07c6c58db3582cE.exit"

"_ZN4core5array40_$LT$impl$u20$$u5b$T$u3b$$u20$N$u5d$$GT$3map17hdb07c6c58db3582cE.exit": ; preds = %"_ZN4core5array40_$LT$impl$u20$$u5b$T$u3b$$u20$N$u5d$$GT$3map21MapGuard$LT$T$C$_$GT$4push17h4ac8fd7710fd6f9dE.exit.i.2.i"
  %27 = lshr i128 %_7.sroa.0.0.copyload.i.i.i.i, 64
  %28 = trunc i128 %27 to i32
  %phi.cast.i.i.2.i = uitofp i32 %28 to float
  %29 = lshr i128 %_7.sroa.0.0.copyload.i.i.i.i, 32
  %30 = trunc i128 %29 to i32
  %phi.cast.i.i.1.i = uitofp i32 %30 to float
  %31 = trunc i128 %_7.sroa.0.0.copyload.i.i.i.i to i32
  %phi.cast.i.i.i = uitofp i32 %31 to float
  call void @llvm.lifetime.end.p0i8(i64 4, i8* nonnull %11) #3, !noalias !11
  %32 = lshr i128 %_7.sroa.0.0.copyload.i.i.i.i, 96
  %33 = trunc i128 %32 to i32
  %phi.cast.i.i.3.i = uitofp i32 %33 to float
  call void @llvm.lifetime.end.p0i8(i64 32, i8* nonnull %6), !noalias !8
  %34 = bitcast float %phi.cast.i.i.i to i32
  %35 = bitcast float %phi.cast.i.i.1.i to i32
  %36 = bitcast float %phi.cast.i.i.2.i to i32
  %37 = bitcast float %phi.cast.i.i.3.i to i32
  %buffer.i.sroa.6.0.insert.ext = zext i32 %37 to i128
  %buffer.i.sroa.6.0.insert.shift = shl nuw i128 %buffer.i.sroa.6.0.insert.ext, 96
  %buffer.i.sroa.5.0.insert.ext = zext i32 %36 to i128
  %buffer.i.sroa.5.0.insert.shift = shl nuw nsw i128 %buffer.i.sroa.5.0.insert.ext, 64
  %buffer.i.sroa.4.0.insert.ext = zext i32 %35 to i128
  %buffer.i.sroa.4.0.insert.shift = shl nuw nsw i128 %buffer.i.sroa.4.0.insert.ext, 32
  %buffer.i.sroa.0.0.insert.ext = zext i32 %34 to i128
  %buffer.i.sroa.5.0.insert.insert = or i128 %buffer.i.sroa.5.0.insert.shift, %buffer.i.sroa.0.0.insert.ext
  %buffer.i.sroa.4.0.insert.insert = or i128 %buffer.i.sroa.5.0.insert.insert, %buffer.i.sroa.6.0.insert.shift
  %buffer.i.sroa.0.0.insert.insert = or i128 %buffer.i.sroa.4.0.insert.insert, %buffer.i.sroa.4.0.insert.shift
  ret i128 %buffer.i.sroa.0.0.insert.insert
}

; Function Attrs: nounwind nonlazybind uwtable
define void @array_cast_to_u64([4 x i64]* noalias nocapture sret dereferenceable(32) %0, i128 %1) unnamed_addr #0 personality i32 (i32, i32, i64, %"unwind::libunwind::_Unwind_Exception"*, %"unwind::libunwind::_Unwind_Context"*)* @rust_eh_personality {
start:
  %tmp.i.i.i.i.i2.i.i.i.i = alloca i32, align 4
  %tmp.i.i.i.i.i.i.i.i.i = alloca i64, align 8
  %src.i.i.i.i.i.i = alloca i64, align 8
  %iter1.i.i = alloca %"std::iter::Map<std::array::IntoIter<u32, 4_usize>, [closure@/home/kadmin/projects/rust/src/test/codegen/array-map.rs:25:9: 25:21]>", align 16
  %tmp.i.i.i.i = alloca i128, align 8
  %array.i.i = alloca i128, align 8
  %2 = bitcast i128* %array.i.i to i8*
  call void @llvm.lifetime.start.p0i8(i64 16, i8* nonnull %2), !noalias !19
  store i128 %1, i128* %array.i.i, align 8, !noalias !22
  %3 = bitcast i128* %tmp.i.i.i.i to i8*
  call void @llvm.lifetime.start.p0i8(i64 16, i8* nonnull %3) #3, !noalias !25
  %_6.i.i.i.i.i.i = ptrtoint i128* %array.i.i to i64
  %_6.i2.i.i.i.i.i = ptrtoint i128* %tmp.i.i.i.i to i64
  %_13.i.i.i.i.i.i = icmp ult i128* %tmp.i.i.i.i, %array.i.i
  %4 = sub i64 %_6.i.i.i.i.i.i, %_6.i2.i.i.i.i.i
  %5 = sub i64 %_6.i2.i.i.i.i.i, %_6.i.i.i.i.i.i
  %diff.0.i.i.i.i.i.i = select i1 %_13.i.i.i.i.i.i, i64 %4, i64 %5
  %6 = icmp ugt i64 %diff.0.i.i.i.i.i.i, 15
  br i1 %6, label %bb3.i.i.i.lr.ph.i.i, label %bb16.i.i.i.i.i

bb16.i.i.i.i.i:                                   ; preds = %start
  call void @llvm.trap() #3, !noalias !22
  unreachable

bb3.i.i.i.lr.ph.i.i:                              ; preds = %start
  call void @llvm.memcpy.p0i8.p0i8.i64(i8* nonnull align 8 dereferenceable(16) %3, i8* nonnull align 8 dereferenceable(16) %2, i64 16, i1 false) #3, !noalias !22
  %_7.sroa.0.0.copyload.i.i.i.i = load i128, i128* %tmp.i.i.i.i, align 8, !noalias !25
  call void @llvm.lifetime.end.p0i8(i64 16, i8* nonnull %3) #3, !noalias !25
  call void @llvm.lifetime.end.p0i8(i64 16, i8* nonnull %2), !noalias !19
  %7 = getelementptr inbounds %"std::iter::Map<std::array::IntoIter<u32, 4_usize>, [closure@/home/kadmin/projects/rust/src/test/codegen/array-map.rs:25:9: 25:21]>", %"std::iter::Map<std::array::IntoIter<u32, 4_usize>, [closure@/home/kadmin/projects/rust/src/test/codegen/array-map.rs:25:9: 25:21]>"* %iter1.i.i, i64 0, i32 0, i64 0
  call void @llvm.lifetime.start.p0i8(i64 32, i8* nonnull %7), !noalias !28
  %_8.sroa.0.sroa.0.0._8.sroa.0.0..sroa_idx.sroa_cast.i = bitcast %"std::iter::Map<std::array::IntoIter<u32, 4_usize>, [closure@/home/kadmin/projects/rust/src/test/codegen/array-map.rs:25:9: 25:21]>"* %iter1.i.i to i64*
  %8 = bitcast %"std::iter::Map<std::array::IntoIter<u32, 4_usize>, [closure@/home/kadmin/projects/rust/src/test/codegen/array-map.rs:25:9: 25:21]>"* %iter1.i.i to <2 x i64>*
  store <2 x i64> <i64 0, i64 4>, <2 x i64>* %8, align 16, !noalias !19
  %_8.sroa.0.sroa.5.0._8.sroa.0.0..sroa_idx.sroa_idx.i = getelementptr inbounds %"std::iter::Map<std::array::IntoIter<u32, 4_usize>, [closure@/home/kadmin/projects/rust/src/test/codegen/array-map.rs:25:9: 25:21]>", %"std::iter::Map<std::array::IntoIter<u32, 4_usize>, [closure@/home/kadmin/projects/rust/src/test/codegen/array-map.rs:25:9: 25:21]>"* %iter1.i.i, i64 0, i32 3, i32 3
  %_8.sroa.0.sroa.5.0._8.sroa.0.0..sroa_idx.sroa_cast.i = bitcast [4 x i32]* %_8.sroa.0.sroa.5.0._8.sroa.0.0..sroa_idx.sroa_idx.i to i128*
  store i128 %_7.sroa.0.0.copyload.i.i.i.i, i128* %_8.sroa.0.sroa.5.0._8.sroa.0.0..sroa_idx.sroa_cast.i, align 16, !noalias !19
  %9 = bitcast i64* %src.i.i.i.i.i.i to i8*
  %_6.i.i.i.i.i.i.i.i.i.i.i = ptrtoint %"std::iter::Map<std::array::IntoIter<u32, 4_usize>, [closure@/home/kadmin/projects/rust/src/test/codegen/array-map.rs:25:9: 25:21]>"* %iter1.i.i to i64
  %_6.i2.i.i.i.i.i.i.i.i.i.i = ptrtoint i64* %tmp.i.i.i.i.i.i.i.i.i to i64
  %_13.i.i.i.i.i.i.i.i.i.i.i = icmp ult i64* %tmp.i.i.i.i.i.i.i.i.i, %_8.sroa.0.sroa.0.0._8.sroa.0.0..sroa_idx.sroa_cast.i
  %10 = sub i64 %_6.i.i.i.i.i.i.i.i.i.i.i, %_6.i2.i.i.i.i.i.i.i.i.i.i
  %11 = sub i64 %_6.i2.i.i.i.i.i.i.i.i.i.i, %_6.i.i.i.i.i.i.i.i.i.i.i
  %diff.0.i.i.i.i.i.i.i.i.i.i.i = select i1 %_13.i.i.i.i.i.i.i.i.i.i.i, i64 %10, i64 %11
  %.not.i.i.i.i.i.i.i = icmp eq i64 %diff.0.i.i.i.i.i.i.i.i.i.i.i, 0
  %_6.i.i4.i.i.i.i.i.i.i.i = ptrtoint i64* %src.i.i.i.i.i.i to i64
  %12 = bitcast i32* %tmp.i.i.i.i.i2.i.i.i.i to i8*
  %_6.i2.i.i.i.i.i.i4.i.i.i.i = ptrtoint i32* %tmp.i.i.i.i.i2.i.i.i.i to i64
  br i1 %.not.i.i.i.i.i.i.i, label %bb3.i.i.i.us.i.i, label %bb3.i.i.i.lr.ph.split.i.i

bb3.i.i.i.us.i.i:                                 ; preds = %bb3.i.i.i.lr.ph.i.i
  %13 = bitcast i64* %tmp.i.i.i.i.i.i.i.i.i to i8*
  call void @llvm.lifetime.start.p0i8(i64 8, i8* nonnull %9) #3, !noalias !28
  store i64 1, i64* %src.i.i.i.i.i.i, align 8, !noalias !28
  call void @llvm.lifetime.start.p0i8(i64 8, i8* nonnull %13) #3, !noalias !28
  call void @llvm.trap() #3, !noalias !28
  unreachable

bb3.i.i.i.lr.ph.split.i.i:                        ; preds = %bb3.i.i.i.lr.ph.i.i
  %_13.i.i.i.i.i.i.i.i.i.i = icmp ugt i64* %src.i.i.i.i.i.i, %_8.sroa.0.sroa.0.0._8.sroa.0.0..sroa_idx.sroa_cast.i
  %14 = sub i64 %_6.i.i4.i.i.i.i.i.i.i.i, %_6.i.i.i.i.i.i.i.i.i.i.i
  %15 = sub i64 %_6.i.i.i.i.i.i.i.i.i.i.i, %_6.i.i4.i.i.i.i.i.i.i.i
  %diff.0.i.i.i.i.i.i.i.i.i.i = select i1 %_13.i.i.i.i.i.i.i.i.i.i, i64 %14, i64 %15
  %.not1.i.i.i.i.i.i.i = icmp eq i64 %diff.0.i.i.i.i.i.i.i.i.i.i, 0
  br i1 %.not1.i.i.i.i.i.i.i, label %bb3.i.i.i.us40.i.i, label %bb3.i.i.i.i.preheader.i

bb3.i.i.i.i.preheader.i:                          ; preds = %bb3.i.i.i.lr.ph.split.i.i
  %16 = getelementptr inbounds %"std::iter::Map<std::array::IntoIter<u32, 4_usize>, [closure@/home/kadmin/projects/rust/src/test/codegen/array-map.rs:25:9: 25:21]>", %"std::iter::Map<std::array::IntoIter<u32, 4_usize>, [closure@/home/kadmin/projects/rust/src/test/codegen/array-map.rs:25:9: 25:21]>"* %iter1.i.i, i64 0, i32 3, i32 3, i64 0
  call void @llvm.lifetime.start.p0i8(i64 4, i8* nonnull %12) #3, !noalias !31
  %_6.i.i.i.i.i.i.i3.i.i.i.i = ptrtoint i32* %16 to i64
  %_13.i.i.i.i.i.i.i5.i.i.i.i = icmp ult i32* %tmp.i.i.i.i.i2.i.i.i.i, %16
  %17 = sub i64 %_6.i.i.i.i.i.i.i3.i.i.i.i, %_6.i2.i.i.i.i.i.i4.i.i.i.i
  %18 = sub i64 %_6.i2.i.i.i.i.i.i4.i.i.i.i, %_6.i.i.i.i.i.i.i3.i.i.i.i
  %diff.0.i.i.i.i.i.i.i6.i.i.i.i = select i1 %_13.i.i.i.i.i.i.i5.i.i.i.i, i64 %17, i64 %18
  %.not.i.i.i7.i.i.i.i = icmp eq i64 %diff.0.i.i.i.i.i.i.i6.i.i.i.i, 0
  br i1 %.not.i.i.i7.i.i.i.i, label %bb16.i.i.i.i.i.i9.i.i.i.i, label %"_ZN4core5array40_$LT$impl$u20$$u5b$T$u3b$$u20$N$u5d$$GT$3map21MapGuard$LT$T$C$_$GT$4push17h20a5840875d0cfddE.exit.i.i"

bb3.i.i.i.us40.i.i:                               ; preds = %bb3.i.i.i.lr.ph.split.i.i
  call void @llvm.lifetime.start.p0i8(i64 8, i8* nonnull %9) #3, !noalias !28
  store i64 1, i64* %src.i.i.i.i.i.i, align 8, !noalias !28
  call void @llvm.trap() #3, !noalias !28
  unreachable

bb16.i.i.i.i.i.i9.i.i.i.i:                        ; preds = %"_ZN4core5array40_$LT$impl$u20$$u5b$T$u3b$$u20$N$u5d$$GT$3map21MapGuard$LT$T$C$_$GT$4push17h20a5840875d0cfddE.exit.i.2.i", %"_ZN4core5array40_$LT$impl$u20$$u5b$T$u3b$$u20$N$u5d$$GT$3map21MapGuard$LT$T$C$_$GT$4push17h20a5840875d0cfddE.exit.i.1.i", %"_ZN4core5array40_$LT$impl$u20$$u5b$T$u3b$$u20$N$u5d$$GT$3map21MapGuard$LT$T$C$_$GT$4push17h20a5840875d0cfddE.exit.i.i", %bb3.i.i.i.i.preheader.i
  %.lcssa.i = phi i64 [ 1, %bb3.i.i.i.i.preheader.i ], [ 2, %"_ZN4core5array40_$LT$impl$u20$$u5b$T$u3b$$u20$N$u5d$$GT$3map21MapGuard$LT$T$C$_$GT$4push17h20a5840875d0cfddE.exit.i.i" ], [ 3, %"_ZN4core5array40_$LT$impl$u20$$u5b$T$u3b$$u20$N$u5d$$GT$3map21MapGuard$LT$T$C$_$GT$4push17h20a5840875d0cfddE.exit.i.1.i" ], [ 4, %"_ZN4core5array40_$LT$impl$u20$$u5b$T$u3b$$u20$N$u5d$$GT$3map21MapGuard$LT$T$C$_$GT$4push17h20a5840875d0cfddE.exit.i.2.i" ]
  store i64 %.lcssa.i, i64* %_8.sroa.0.sroa.0.0._8.sroa.0.0..sroa_idx.sroa_cast.i, align 16, !noalias !28
  call void @llvm.trap() #3, !noalias !38
  unreachable

"_ZN4core5array40_$LT$impl$u20$$u5b$T$u3b$$u20$N$u5d$$GT$3map21MapGuard$LT$T$C$_$GT$4push17h20a5840875d0cfddE.exit.i.i": ; preds = %bb3.i.i.i.i.preheader.i
  call void @llvm.lifetime.end.p0i8(i64 4, i8* nonnull %12) #3, !noalias !31
  %19 = getelementptr inbounds %"std::iter::Map<std::array::IntoIter<u32, 4_usize>, [closure@/home/kadmin/projects/rust/src/test/codegen/array-map.rs:25:9: 25:21]>", %"std::iter::Map<std::array::IntoIter<u32, 4_usize>, [closure@/home/kadmin/projects/rust/src/test/codegen/array-map.rs:25:9: 25:21]>"* %iter1.i.i, i64 0, i32 3, i32 3, i64 1
  call void @llvm.lifetime.start.p0i8(i64 4, i8* nonnull %12) #3, !noalias !31
  %_6.i.i.i.i.i.i.i3.i.i.i.1.i = ptrtoint i32* %19 to i64
  %_13.i.i.i.i.i.i.i5.i.i.i.1.i = icmp ult i32* %tmp.i.i.i.i.i2.i.i.i.i, %19
  %20 = sub i64 %_6.i.i.i.i.i.i.i3.i.i.i.1.i, %_6.i2.i.i.i.i.i.i4.i.i.i.i
  %21 = sub i64 %_6.i2.i.i.i.i.i.i4.i.i.i.i, %_6.i.i.i.i.i.i.i3.i.i.i.1.i
  %diff.0.i.i.i.i.i.i.i6.i.i.i.1.i = select i1 %_13.i.i.i.i.i.i.i5.i.i.i.1.i, i64 %20, i64 %21
  %.not.i.i.i7.i.i.i.1.i = icmp eq i64 %diff.0.i.i.i.i.i.i.i6.i.i.i.1.i, 0
  br i1 %.not.i.i.i7.i.i.i.1.i, label %bb16.i.i.i.i.i.i9.i.i.i.i, label %"_ZN4core5array40_$LT$impl$u20$$u5b$T$u3b$$u20$N$u5d$$GT$3map21MapGuard$LT$T$C$_$GT$4push17h20a5840875d0cfddE.exit.i.1.i"

"_ZN4core5array40_$LT$impl$u20$$u5b$T$u3b$$u20$N$u5d$$GT$3map21MapGuard$LT$T$C$_$GT$4push17h20a5840875d0cfddE.exit.i.1.i": ; preds = %"_ZN4core5array40_$LT$impl$u20$$u5b$T$u3b$$u20$N$u5d$$GT$3map21MapGuard$LT$T$C$_$GT$4push17h20a5840875d0cfddE.exit.i.i"
  call void @llvm.lifetime.end.p0i8(i64 4, i8* nonnull %12) #3, !noalias !31
  %22 = getelementptr inbounds %"std::iter::Map<std::array::IntoIter<u32, 4_usize>, [closure@/home/kadmin/projects/rust/src/test/codegen/array-map.rs:25:9: 25:21]>", %"std::iter::Map<std::array::IntoIter<u32, 4_usize>, [closure@/home/kadmin/projects/rust/src/test/codegen/array-map.rs:25:9: 25:21]>"* %iter1.i.i, i64 0, i32 3, i32 3, i64 2
  call void @llvm.lifetime.start.p0i8(i64 4, i8* nonnull %12) #3, !noalias !31
  %_6.i.i.i.i.i.i.i3.i.i.i.2.i = ptrtoint i32* %22 to i64
  %_13.i.i.i.i.i.i.i5.i.i.i.2.i = icmp ult i32* %tmp.i.i.i.i.i2.i.i.i.i, %22
  %23 = sub i64 %_6.i.i.i.i.i.i.i3.i.i.i.2.i, %_6.i2.i.i.i.i.i.i4.i.i.i.i
  %24 = sub i64 %_6.i2.i.i.i.i.i.i4.i.i.i.i, %_6.i.i.i.i.i.i.i3.i.i.i.2.i
  %diff.0.i.i.i.i.i.i.i6.i.i.i.2.i = select i1 %_13.i.i.i.i.i.i.i5.i.i.i.2.i, i64 %23, i64 %24
  %.not.i.i.i7.i.i.i.2.i = icmp eq i64 %diff.0.i.i.i.i.i.i.i6.i.i.i.2.i, 0
  br i1 %.not.i.i.i7.i.i.i.2.i, label %bb16.i.i.i.i.i.i9.i.i.i.i, label %"_ZN4core5array40_$LT$impl$u20$$u5b$T$u3b$$u20$N$u5d$$GT$3map21MapGuard$LT$T$C$_$GT$4push17h20a5840875d0cfddE.exit.i.2.i"

"_ZN4core5array40_$LT$impl$u20$$u5b$T$u3b$$u20$N$u5d$$GT$3map21MapGuard$LT$T$C$_$GT$4push17h20a5840875d0cfddE.exit.i.2.i": ; preds = %"_ZN4core5array40_$LT$impl$u20$$u5b$T$u3b$$u20$N$u5d$$GT$3map21MapGuard$LT$T$C$_$GT$4push17h20a5840875d0cfddE.exit.i.1.i"
  call void @llvm.lifetime.end.p0i8(i64 4, i8* nonnull %12) #3, !noalias !31
  %25 = getelementptr inbounds %"std::iter::Map<std::array::IntoIter<u32, 4_usize>, [closure@/home/kadmin/projects/rust/src/test/codegen/array-map.rs:25:9: 25:21]>", %"std::iter::Map<std::array::IntoIter<u32, 4_usize>, [closure@/home/kadmin/projects/rust/src/test/codegen/array-map.rs:25:9: 25:21]>"* %iter1.i.i, i64 0, i32 3, i32 3, i64 3
  call void @llvm.lifetime.start.p0i8(i64 4, i8* nonnull %12) #3, !noalias !31
  %_6.i.i.i.i.i.i.i3.i.i.i.3.i = ptrtoint i32* %25 to i64
  %_13.i.i.i.i.i.i.i5.i.i.i.3.i = icmp ult i32* %tmp.i.i.i.i.i2.i.i.i.i, %25
  %26 = sub i64 %_6.i.i.i.i.i.i.i3.i.i.i.3.i, %_6.i2.i.i.i.i.i.i4.i.i.i.i
  %27 = sub i64 %_6.i2.i.i.i.i.i.i4.i.i.i.i, %_6.i.i.i.i.i.i.i3.i.i.i.3.i
  %diff.0.i.i.i.i.i.i.i6.i.i.i.3.i = select i1 %_13.i.i.i.i.i.i.i5.i.i.i.3.i, i64 %26, i64 %27
  %.not.i.i.i7.i.i.i.3.i = icmp eq i64 %diff.0.i.i.i.i.i.i.i6.i.i.i.3.i, 0
  br i1 %.not.i.i.i7.i.i.i.3.i, label %bb16.i.i.i.i.i.i9.i.i.i.i, label %"_ZN4core5array40_$LT$impl$u20$$u5b$T$u3b$$u20$N$u5d$$GT$3map17h67a9fe77bbbd92e0E.exit"

"_ZN4core5array40_$LT$impl$u20$$u5b$T$u3b$$u20$N$u5d$$GT$3map17h67a9fe77bbbd92e0E.exit": ; preds = %"_ZN4core5array40_$LT$impl$u20$$u5b$T$u3b$$u20$N$u5d$$GT$3map21MapGuard$LT$T$C$_$GT$4push17h20a5840875d0cfddE.exit.i.2.i"
  %28 = lshr i128 %_7.sroa.0.0.copyload.i.i.i.i, 64
  %29 = trunc i128 %28 to i64
  %phi.cast.i.i.2.i = and i64 %29, 4294967295
  %30 = lshr i128 %_7.sroa.0.0.copyload.i.i.i.i, 32
  %31 = insertelement <2 x i128> undef, i128 %_7.sroa.0.0.copyload.i.i.i.i, i32 0
  %32 = insertelement <2 x i128> %31, i128 %30, i32 1
  %33 = trunc <2 x i128> %32 to <2 x i64>
  %34 = and <2 x i64> %33, <i64 4294967295, i64 4294967295>
  call void @llvm.lifetime.end.p0i8(i64 4, i8* nonnull %12) #3, !noalias !31
  %35 = lshr i128 %_7.sroa.0.0.copyload.i.i.i.i, 96
  %36 = trunc i128 %35 to i64
  call void @llvm.lifetime.end.p0i8(i64 32, i8* nonnull %7), !noalias !28
  %37 = bitcast [4 x i64]* %0 to <2 x i64>*
  store <2 x i64> %34, <2 x i64>* %37, align 8
  %buffer.i.sroa.5.0..sroa_idx7 = getelementptr inbounds [4 x i64], [4 x i64]* %0, i64 0, i64 2
  store i64 %phi.cast.i.i.2.i, i64* %buffer.i.sroa.5.0..sroa_idx7, align 8
  %buffer.i.sroa.6.0..sroa_idx9 = getelementptr inbounds [4 x i64], [4 x i64]* %0, i64 0, i64 3
  store i64 %36, i64* %buffer.i.sroa.6.0..sroa_idx9, align 8
  ret void
}

; Function Attrs: argmemonly nounwind willreturn
declare void @llvm.lifetime.start.p0i8(i64 immarg, i8* nocapture) #1

; Function Attrs: argmemonly nounwind willreturn
declare void @llvm.lifetime.end.p0i8(i64 immarg, i8* nocapture) #1

; Function Attrs: cold noreturn nounwind
declare void @llvm.trap() #2

; Function Attrs: argmemonly nounwind willreturn
declare void @llvm.memcpy.p0i8.p0i8.i64(i8* noalias nocapture writeonly, i8* noalias nocapture readonly, i64, i1 immarg) #1

; Function Attrs: nounwind nonlazybind uwtable
declare i32 @rust_eh_personality(i32, i32, i64, %"unwind::libunwind::_Unwind_Exception"*, %"unwind::libunwind::_Unwind_Context"*) unnamed_addr #0

attributes #0 = { nounwind nonlazybind uwtable "probe-stack"="__rust_probestack" "target-cpu"="x86-64" }
attributes #1 = { argmemonly nounwind willreturn }
attributes #2 = { cold noreturn nounwind }
attributes #3 = { nounwind }

!llvm.module.flags = !{!0, !1}

!0 = !{i32 7, !"PIC Level", i32 2}
!1 = !{i32 2, !"RtLibUseGOT", i32 1}
!2 = !{!3}
!3 = distinct !{!3, !4, !"_ZN4core5array4iter21IntoIter$LT$T$C$_$GT$3new17h08b5d275cb899f9cE: %iter"}
!4 = distinct !{!4, !"_ZN4core5array4iter21IntoIter$LT$T$C$_$GT$3new17h08b5d275cb899f9cE"}
!5 = !{!6, !3}
!6 = distinct !{!6, !7, !"_ZN4core3mem14transmute_copy17hdca171785ff334f2E: %src"}
!7 = distinct !{!7, !"_ZN4core3mem14transmute_copy17hdca171785ff334f2E"}
!8 = !{!9}
!9 = distinct !{!9, !10, !"_ZN4core5array40_$LT$impl$u20$$u5b$T$u3b$$u20$N$u5d$$GT$3map12map_guard_fn17h8248582cb705ef25E: %iter"}
!10 = distinct !{!10, !"_ZN4core5array40_$LT$impl$u20$$u5b$T$u3b$$u20$N$u5d$$GT$3map12map_guard_fn17h8248582cb705ef25E"}
!11 = !{!12, !14, !16, !9}
!12 = distinct !{!12, !13, !"_ZN4core3mem12maybe_uninit20MaybeUninit$LT$T$GT$16assume_init_read17hace13e682fd6db62E: %self"}
!13 = distinct !{!13, !"_ZN4core3mem12maybe_uninit20MaybeUninit$LT$T$GT$16assume_init_read17hace13e682fd6db62E"}
!14 = distinct !{!14, !15, !"_ZN99_$LT$core..array..iter..IntoIter$LT$T$C$_$GT$$u20$as$u20$core..iter..traits..iterator..Iterator$GT$4next28_$u7b$$u7b$closure$u7d$$u7d$17h5922dc1006c3a4a1E: %_1"}
!15 = distinct !{!15, !"_ZN99_$LT$core..array..iter..IntoIter$LT$T$C$_$GT$$u20$as$u20$core..iter..traits..iterator..Iterator$GT$4next28_$u7b$$u7b$closure$u7d$$u7d$17h5922dc1006c3a4a1E"}
!16 = distinct !{!16, !17, !"_ZN4core6option15Option$LT$T$GT$3map17hf8dbcf446d7e5ba8E: %f"}
!17 = distinct !{!17, !"_ZN4core6option15Option$LT$T$GT$3map17hf8dbcf446d7e5ba8E"}
!18 = !{!14, !16, !9}
!19 = !{!20}
!20 = distinct !{!20, !21, !"_ZN4core5array40_$LT$impl$u20$$u5b$T$u3b$$u20$N$u5d$$GT$3map17h67a9fe77bbbd92e0E: argument 0"}
!21 = distinct !{!21, !"_ZN4core5array40_$LT$impl$u20$$u5b$T$u3b$$u20$N$u5d$$GT$3map17h67a9fe77bbbd92e0E"}
!22 = !{!23, !20}
!23 = distinct !{!23, !24, !"_ZN4core5array4iter21IntoIter$LT$T$C$_$GT$3new17h08b5d275cb899f9cE: %iter"}
!24 = distinct !{!24, !"_ZN4core5array4iter21IntoIter$LT$T$C$_$GT$3new17h08b5d275cb899f9cE"}
!25 = !{!26, !23, !20}
!26 = distinct !{!26, !27, !"_ZN4core3mem14transmute_copy17hdca171785ff334f2E: %src"}
!27 = distinct !{!27, !"_ZN4core3mem14transmute_copy17hdca171785ff334f2E"}
!28 = !{!29, !20}
!29 = distinct !{!29, !30, !"_ZN4core5array40_$LT$impl$u20$$u5b$T$u3b$$u20$N$u5d$$GT$3map12map_guard_fn17hdd217a46e8be43e7E: %iter"}
!30 = distinct !{!30, !"_ZN4core5array40_$LT$impl$u20$$u5b$T$u3b$$u20$N$u5d$$GT$3map12map_guard_fn17hdd217a46e8be43e7E"}
!31 = !{!32, !34, !36, !29, !20}
!32 = distinct !{!32, !33, !"_ZN4core3mem12maybe_uninit20MaybeUninit$LT$T$GT$16assume_init_read17hace13e682fd6db62E: %self"}
!33 = distinct !{!33, !"_ZN4core3mem12maybe_uninit20MaybeUninit$LT$T$GT$16assume_init_read17hace13e682fd6db62E"}
!34 = distinct !{!34, !35, !"_ZN99_$LT$core..array..iter..IntoIter$LT$T$C$_$GT$$u20$as$u20$core..iter..traits..iterator..Iterator$GT$4next28_$u7b$$u7b$closure$u7d$$u7d$17h5922dc1006c3a4a1E: %_1"}
!35 = distinct !{!35, !"_ZN99_$LT$core..array..iter..IntoIter$LT$T$C$_$GT$$u20$as$u20$core..iter..traits..iterator..Iterator$GT$4next28_$u7b$$u7b$closure$u7d$$u7d$17h5922dc1006c3a4a1E"}
!36 = distinct !{!36, !37, !"_ZN4core6option15Option$LT$T$GT$3map17hf8dbcf446d7e5ba8E: %f"}
!37 = distinct !{!37, !"_ZN4core6option15Option$LT$T$GT$3map17hf8dbcf446d7e5ba8E"}
!38 = !{!34, !36, !29, !20}

[scottmcm]

Thanks. Unfortunately, that confirmed what I was afraid of. Putting these tests in godbolt https://rust.godbolt.org/z/9MoTeb says that array_cast_to_float has two 16-byte allocas, and the IR from the new one looks like it has three:

  %iter1.i.i = alloca %"std::iter::Map<std::array::IntoIter<u32, 4_usize>, [closure@/home/kadmin/projects/rust/src/test/codegen/array-map.rs:14:9: 14:21]>", align 16
  %tmp.i.i.i.i = alloca i128, align 8
  %array.i.i = alloca i128, align 8

I worry I might have steered you wrong earlier and that my demo was just getting lucky with unrolling or something. More generally, it might just not be possible to fix this until there's a resolution to #79914 or similar -- copying the arrays into wrappers, be that array::IntoIter or MaybeUninit or ManuallyDrop, just seems not to reliably optimize out right now.

[bors]

☔ The latest upstream changes (presumably #79607) made this pull request unmergeable. Please resolve the merge conflicts.

Note that reviewers usually do not review pull requests until merge conflicts are resolved! Once you resolve the conflicts, you should change the labels applied by bors to indicate that your PR is ready for review. Post this as a comment to change the labels:

@rustbot modify labels: +S-waiting-on-review -S-waiting-on-author

[JulianKnodt]

I'm going to leave this up, but probably won't update it too much while the manually drop issue is still pending.

[crlf0710]

Triage: I'm gonna switch this to S-blocked now.

[scottmcm]

@JulianKnodt Now that #82098 has gone in, I think I'm going to close this since it'll need redoing to with with that anyway, and as you say it's probably not worth doing that until the ManuallyDrop issue can be resolved.

You can of course reopen at any point, or make a new one if you'd like.