[only tests] Add tests for current read/write unaligned behaviour by scottmcm · Pull Request #158341 · rust-lang/rust

scottmcm · 2026-06-24T04:02:39Z

This adds some tests to record what we're currently doing for read_unaligned and write_unaligned.

I had part of this in #158202, but I'm going to close that in favour of a different approach (#158291 being the first part of that) so figured I'd check in tests showing current behaviour to help make the fix PRs clearer.

rustbot · 2026-06-24T04:02:50Z

r? @mejrs

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mejrs · 2026-06-24T10:55:35Z

I'm not qualified to review this sort of stuff

r? @folkertdev perhaps?

scottmcm · 2026-06-25T05:06:10Z

Moving to draft because it'll conflict with #158345

rust-log-analyzer · 2026-06-25T05:44:09Z

The job aarch64-gnu-llvm-21-1 failed! Check out the build log: (web) (plain enhanced) (plain)

Click to see the possible cause of the failure (guessed by this bot)


---- [codegen] tests/codegen-llvm/read_write_unaligned.rs stdout ----
------FileCheck stdout------------------------------

------FileCheck stderr------------------------------
/checkout/tests/codegen-llvm/read_write_unaligned.rs:27:17: error: CHECK-NEXT: is not on the line after the previous match
 // CHECK-NEXT: ret i16 [[TEMP]]
                ^
/checkout/obj/build/aarch64-unknown-linux-gnu/test/codegen-llvm/read_write_unaligned/read_write_unaligned.ll:19:2: note: 'next' match was here
 ret i16 %_2.sroa.0.0.copyload
 ^
/checkout/obj/build/aarch64-unknown-linux-gnu/test/codegen-llvm/read_write_unaligned/read_write_unaligned.ll:16:53: note: previous match ended here
 %_2.sroa.0.0.copyload = load i16, ptr %ptr, align 1
                                                    ^
/checkout/obj/build/aarch64-unknown-linux-gnu/test/codegen-llvm/read_write_unaligned/read_write_unaligned.ll:17:1: note: non-matching line after previous match is here
 %0 = icmp ne i16 %_2.sroa.0.0.copyload, 0
^

Input file: /checkout/obj/build/aarch64-unknown-linux-gnu/test/codegen-llvm/read_write_unaligned/read_write_unaligned.ll
Check file: /checkout/tests/codegen-llvm/read_write_unaligned.rs

-dump-input=help explains the following input dump.

Input was:
<<<<<<
         1: ; ModuleID = 'read_write_unaligned.e30f5481d8566fd2-cgu.0' 
         2: source_filename = "read_write_unaligned.e30f5481d8566fd2-cgu.0" 
         3: target datalayout = "e-m:e-p270:32:32-p271:32:32-p272:64:64-i8:8:32-i16:16:32-i64:64-i128:128-n32:64-S128-Fn32" 
         4: target triple = "aarch64-unknown-linux-gnu" 
         5:  
         6: ; Function Attrs: mustprogress nofree norecurse nosync nounwind willreturn memory(argmem: read) uwtable 
         7: define noundef nonnull ptr @read_unaligned_ptr(ptr noundef readonly captures(none) %ptr) unnamed_addr #0 { 
         8: start: 
         9:  %_2.sroa.0.0.copyload = load ptr, ptr %ptr, align 1, !nonnull !4, !noundef !4 
        10:  ret ptr %_2.sroa.0.0.copyload 
        11: } 
        12:  
        13: ; Function Attrs: mustprogress nofree norecurse nosync nounwind willreturn memory(argmem: read, inaccessiblemem: write) uwtable 
        14: define noundef range(i16 1, 0) i16 @read_unaligned_i16(ptr noundef readonly captures(none) %ptr) unnamed_addr #1 { 
        15: start: 
        16:  %_2.sroa.0.0.copyload = load i16, ptr %ptr, align 1 
        17:  %0 = icmp ne i16 %_2.sroa.0.0.copyload, 0 
        18:  tail call void @llvm.assume(i1 %0) 
        19:  ret i16 %_2.sroa.0.0.copyload 
next:27      !~~~~~~~~~~~~~~~~~~~~~~~~~~~~  error: match on wrong line
        20: } 
        21:  
        22: ; Function Attrs: mustprogress nofree norecurse nosync nounwind willreturn memory(argmem: readwrite) uwtable 
        23: define void @typed_copy_unaligned_i32(ptr noundef readonly captures(none) %src, ptr noundef writeonly captures(none) initializes((0, 4)) %dst) unnamed_addr #2 { 
        24: start: 
        25:  %_4.sroa.0.0.copyload = load i32, ptr %src, align 1 
        26:  store i32 %_4.sroa.0.0.copyload, ptr %dst, align 1 
        27:  ret void 
        28: } 
        29:  
        30: ; Function Attrs: mustprogress nofree norecurse nosync nounwind willreturn memory(argmem: write) uwtable 
        31: define void @write_unaligned_i64(ptr noundef writeonly captures(none) initializes((0, 8)) %ptr, i64 noundef range(i64 1, 0) %val) unnamed_addr #3 { 
        32: start: 
        33:  store i64 %val, ptr %ptr, align 1 
        34:  ret void 
        35: } 
        36:  
        37: ; Function Attrs: mustprogress nofree norecurse nosync nounwind willreturn memory(argmem: readwrite) uwtable 
        38: define void @read_unaligned_huge(ptr dead_on_unwind noalias nofree noundef writable writeonly sret([8192 x i8]) align 128 captures(none) dereferenceable(8192) initializes((0, 8192)) %_0, ptr noundef readonly captures(none) %ptr) unnamed_addr #2 { 
        39: start: 
        40:  tail call void @llvm.memcpy.p0.p0.i64(ptr noundef nonnull align 128 dereferenceable(8192) %_0, ptr noundef nonnull align 1 dereferenceable(8192) %ptr, i64 8192, i1 false) 
        41:  ret void 
        42: } 
        43:  
        44: ; Function Attrs: mustprogress nofree norecurse nosync nounwind willreturn memory(argmem: readwrite) uwtable 
        45: define void @write_unaligned_huge(ptr noundef writeonly captures(none) initializes((0, 8192)) %ptr, ptr dead_on_return noalias nofree noundef readonly align 128 captures(none) dereferenceable(8192) %val) unnamed_addr #2 { 
        46: start: 
        47:  tail call void @llvm.memcpy.p0.p0.i64(ptr noundef nonnull align 1 dereferenceable(8192) %ptr, ptr noundef nonnull align 128 dereferenceable(8192) %val, i64 8192, i1 false) 
        48:  ret void 
        49: } 
        50:  
        51: ; Function Attrs: mustprogress nocallback nofree nounwind willreturn memory(argmem: readwrite) 
        52: declare void @llvm.memcpy.p0.p0.i64(ptr noalias writeonly captures(none), ptr noalias readonly captures(none), i64, i1 immarg) #4 
        53:  
        54: ; Function Attrs: mustprogress nocallback nofree nosync nounwind willreturn memory(inaccessiblemem: write) 
        55: declare void @llvm.assume(i1 noundef) #5 
        56:  
        57: attributes #0 = { mustprogress nofree norecurse nosync nounwind willreturn memory(argmem: read) uwtable "frame-pointer"="non-leaf" "probe-stack"="inline-asm" "target-cpu"="generic" "target-features"="+v8a,+outline-atomics" } 
        58: attributes #1 = { mustprogress nofree norecurse nosync nounwind willreturn memory(argmem: read, inaccessiblemem: write) uwtable "frame-pointer"="non-leaf" "probe-stack"="inline-asm" "target-cpu"="generic" "target-features"="+v8a,+outline-atomics" } 
        59: attributes #2 = { mustprogress nofree norecurse nosync nounwind willreturn memory(argmem: readwrite) uwtable "frame-pointer"="non-leaf" "probe-stack"="inline-asm" "target-cpu"="generic" "target-features"="+v8a,+outline-atomics" } 
        60: attributes #3 = { mustprogress nofree norecurse nosync nounwind willreturn memory(argmem: write) uwtable "frame-pointer"="non-leaf" "probe-stack"="inline-asm" "target-cpu"="generic" "target-features"="+v8a,+outline-atomics" } 
        61: attributes #4 = { mustprogress nocallback nofree nounwind willreturn memory(argmem: readwrite) } 
        62: attributes #5 = { mustprogress nocallback nofree nosync nounwind willreturn memory(inaccessiblemem: write) } 
        63:  
        64: !llvm.module.flags = !{!0, !1, !2} 
        65: !llvm.ident = !{!3} 
        66:  
        67: !0 = !{i32 8, !"PIC Level", i32 2} 
        68: !1 = !{i32 7, !"uwtable", i32 2} 
        69: !2 = !{i32 7, !"frame-pointer", i32 1} 
        70: !3 = !{!"rustc version 1.98.0-nightly (53db257c2 2026-06-25)"} 
        71: !4 = !{} 
>>>>>>

------------------------------------------

error: verification with 'FileCheck' failed
status: exit status: 1
command: "/usr/lib/llvm-21/bin/FileCheck" "--input-file" "/checkout/obj/build/aarch64-unknown-linux-gnu/test/codegen-llvm/read_write_unaligned/read_write_unaligned.ll" "/checkout/tests/codegen-llvm/read_write_unaligned.rs" "--check-prefix=CHECK" "--allow-unused-prefixes" "--dump-input-context" "100"
stdout: none
--- stderr -------------------------------
/checkout/tests/codegen-llvm/read_write_unaligned.rs:27:17: error: CHECK-NEXT: is not on the line after the previous match
 // CHECK-NEXT: ret i16 [[TEMP]]
                ^
/checkout/obj/build/aarch64-unknown-linux-gnu/test/codegen-llvm/read_write_unaligned/read_write_unaligned.ll:19:2: note: 'next' match was here
 ret i16 %_2.sroa.0.0.copyload
 ^
/checkout/obj/build/aarch64-unknown-linux-gnu/test/codegen-llvm/read_write_unaligned/read_write_unaligned.ll:16:53: note: previous match ended here
 %_2.sroa.0.0.copyload = load i16, ptr %ptr, align 1
                                                    ^
/checkout/obj/build/aarch64-unknown-linux-gnu/test/codegen-llvm/read_write_unaligned/read_write_unaligned.ll:17:1: note: non-matching line after previous match is here
 %0 = icmp ne i16 %_2.sroa.0.0.copyload, 0
^

Input file: /checkout/obj/build/aarch64-unknown-linux-gnu/test/codegen-llvm/read_write_unaligned/read_write_unaligned.ll
Check file: /checkout/tests/codegen-llvm/read_write_unaligned.rs

-dump-input=help explains the following input dump.

Input was:
<<<<<<
         1: ; ModuleID = 'read_write_unaligned.e30f5481d8566fd2-cgu.0' 
         2: source_filename = "read_write_unaligned.e30f5481d8566fd2-cgu.0" 
         3: target datalayout = "e-m:e-p270:32:32-p271:32:32-p272:64:64-i8:8:32-i16:16:32-i64:64-i128:128-n32:64-S128-Fn32" 
         4: target triple = "aarch64-unknown-linux-gnu" 
         5:  
         6: ; Function Attrs: mustprogress nofree norecurse nosync nounwind willreturn memory(argmem: read) uwtable 
         7: define noundef nonnull ptr @read_unaligned_ptr(ptr noundef readonly captures(none) %ptr) unnamed_addr #0 { 
         8: start: 
         9:  %_2.sroa.0.0.copyload = load ptr, ptr %ptr, align 1, !nonnull !4, !noundef !4 
        10:  ret ptr %_2.sroa.0.0.copyload 
        11: } 
        12:  
        13: ; Function Attrs: mustprogress nofree norecurse nosync nounwind willreturn memory(argmem: read, inaccessiblemem: write) uwtable 
        14: define noundef range(i16 1, 0) i16 @read_unaligned_i16(ptr noundef readonly captures(none) %ptr) unnamed_addr #1 { 
        15: start: 
        16:  %_2.sroa.0.0.copyload = load i16, ptr %ptr, align 1 
        17:  %0 = icmp ne i16 %_2.sroa.0.0.copyload, 0 
        18:  tail call void @llvm.assume(i1 %0) 
        19:  ret i16 %_2.sroa.0.0.copyload 
next:27      !~~~~~~~~~~~~~~~~~~~~~~~~~~~~  error: match on wrong line
        20: } 
        21:  
        22: ; Function Attrs: mustprogress nofree norecurse nosync nounwind willreturn memory(argmem: readwrite) uwtable 
        23: define void @typed_copy_unaligned_i32(ptr noundef readonly captures(none) %src, ptr noundef writeonly captures(none) initializes((0, 4)) %dst) unnamed_addr #2 { 
        24: start: 
        25:  %_4.sroa.0.0.copyload = load i32, ptr %src, align 1 
        26:  store i32 %_4.sroa.0.0.copyload, ptr %dst, align 1 
        27:  ret void 
        28: } 
        29:  
        30: ; Function Attrs: mustprogress nofree norecurse nosync nounwind willreturn memory(argmem: write) uwtable 
        31: define void @write_unaligned_i64(ptr noundef writeonly captures(none) initializes((0, 8)) %ptr, i64 noundef range(i64 1, 0) %val) unnamed_addr #3 { 
        32: start: 
        33:  store i64 %val, ptr %ptr, align 1 
        34:  ret void 
        35: } 
        36:  
        37: ; Function Attrs: mustprogress nofree norecurse nosync nounwind willreturn memory(argmem: readwrite) uwtable 
        38: define void @read_unaligned_huge(ptr dead_on_unwind noalias nofree noundef writable writeonly sret([8192 x i8]) align 128 captures(none) dereferenceable(8192) initializes((0, 8192)) %_0, ptr noundef readonly captures(none) %ptr) unnamed_addr #2 { 
        39: start: 
        40:  tail call void @llvm.memcpy.p0.p0.i64(ptr noundef nonnull align 128 dereferenceable(8192) %_0, ptr noundef nonnull align 1 dereferenceable(8192) %ptr, i64 8192, i1 false) 
        41:  ret void 
        42: } 
        43:  
        44: ; Function Attrs: mustprogress nofree norecurse nosync nounwind willreturn memory(argmem: readwrite) uwtable 
        45: define void @write_unaligned_huge(ptr noundef writeonly captures(none) initializes((0, 8192)) %ptr, ptr dead_on_return noalias nofree noundef readonly align 128 captures(none) dereferenceable(8192) %val) unnamed_addr #2 { 
        46: start: 
        47:  tail call void @llvm.memcpy.p0.p0.i64(ptr noundef nonnull align 1 dereferenceable(8192) %ptr, ptr noundef nonnull align 128 dereferenceable(8192) %val, i64 8192, i1 false) 
        48:  ret void 
        49: } 
        50:  
        51: ; Function Attrs: mustprogress nocallback nofree nounwind willreturn memory(argmem: readwrite) 
        52: declare void @llvm.memcpy.p0.p0.i64(ptr noalias writeonly captures(none), ptr noalias readonly captures(none), i64, i1 immarg) #4 
        53:  
        54: ; Function Attrs: mustprogress nocallback nofree nosync nounwind willreturn memory(inaccessiblemem: write) 
        55: declare void @llvm.assume(i1 noundef) #5 
        56:  
        57: attributes #0 = { mustprogress nofree norecurse nosync nounwind willreturn memory(argmem: read) uwtable "frame-pointer"="non-leaf" "probe-stack"="inline-asm" "target-cpu"="generic" "target-features"="+v8a,+outline-atomics" } 
        58: attributes #1 = { mustprogress nofree norecurse nosync nounwind willreturn memory(argmem: read, inaccessiblemem: write) uwtable "frame-pointer"="non-leaf" "probe-stack"="inline-asm" "target-cpu"="generic" "target-features"="+v8a,+outline-atomics" } 
        59: attributes #2 = { mustprogress nofree norecurse nosync nounwind willreturn memory(argmem: readwrite) uwtable "frame-pointer"="non-leaf" "probe-stack"="inline-asm" "target-cpu"="generic" "target-features"="+v8a,+outline-atomics" } 
        60: attributes #3 = { mustprogress nofree norecurse nosync nounwind willreturn memory(argmem: write) uwtable "frame-pointer"="non-leaf" "probe-stack"="inline-asm" "target-cpu"="generic" "target-features"="+v8a,+outline-atomics" } 
        61: attributes #4 = { mustprogress nocallback nofree nounwind willreturn memory(argmem: readwrite) } 
        62: attributes #5 = { mustprogress nocallback nofree nosync nounwind willreturn memory(inaccessiblemem: write) } 
        63:  
        64: !llvm.module.flags = !{!0, !1, !2} 
        65: !llvm.ident = !{!3} 
        66:  
        67: !0 = !{i32 8, !"PIC Level", i32 2} 
        68: !1 = !{i32 7, !"uwtable", i32 2} 
        69: !2 = !{i32 7, !"frame-pointer", i32 1} 
        70: !3 = !{!"rustc version 1.98.0-nightly (53db257c2 2026-06-25)"} 
        71: !4 = !{} 
>>>>>>
------------------------------------------

---- [codegen] tests/codegen-llvm/read_write_unaligned.rs stdout end ----

rustbot added S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. T-compiler Relevant to the compiler team, which will review and decide on the PR/issue. labels Jun 24, 2026

rustbot assigned mejrs Jun 24, 2026

scottmcm mentioned this pull request Jun 24, 2026

Preserve metadata like !range and !nonnull in unaligned operations #158202

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scottmcm force-pushed the unaligned-pinning branch from 177fe9d to d6f80bf Compare June 24, 2026 05:00

rustbot assigned folkertdev and unassigned mejrs Jun 24, 2026

Use transmute_neo in assume_init

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scottmcm marked this pull request as draft June 25, 2026 05:06

rustbot added S-waiting-on-author Status: This is awaiting some action (such as code changes or more information) from the author. and removed S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. labels Jun 25, 2026

Add a test for current read/write unaligned behaviour

6308be0

scottmcm force-pushed the unaligned-pinning branch from d6f80bf to 6308be0 Compare June 25, 2026 05:09

scottmcm closed this Jun 26, 2026

rustbot removed the S-waiting-on-author Status: This is awaiting some action (such as code changes or more information) from the author. label Jun 26, 2026

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[only tests] Add tests for current read/write unaligned behaviour#158341

[only tests] Add tests for current read/write unaligned behaviour#158341
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