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bcardiff/issue-13010.md

Created January 27, 2023 21:00
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  1. bcardiff created this gist Jan 27, 2023.
    106 changes: 106 additions & 0 deletions issue-13010.md
    View file
    Original file line number Diff line number Diff line change
    @@ -0,0 +1,106 @@
    ```
    $ ./bin/crystal --version
    Using compiled compiler at .build/crystal
    Crystal 1.8.0-dev [58fb584cb87] (2023-01-21)
    LLVM: 14.0.1
    Default target: aarch64-apple-darwin21.6.0
    ```

    ```
    $ ./bin/crystal build --emit=llvm-ir -Dpreview_mt bug.ign.cr
    $ llvm-as ./bug.ign.ll -o ./bug.ign.bc
    $ llc ./bug.ign.bc -o ./bug.ign.s
    ```

    ```
    def swap(value : T)
    Ops.atomicrmw(:xchg, pointerof(@value), value, :sequentially_consistent, false)
    end
    ```

    ```
    def codegen_primitive_atomicrmw(call, node, target_def, call_args)
    call = check_atomic_call(call, target_def)
    op, ptr, val, ordering, _ = call_args
    op = atomicrwm_bin_op_get_const(call.args[0], op)
    ordering = atomic_ordering_get_const(call.args[-2], ordering)
    singlethread = bool_from_bool_literal(call.args[-1])
    builder.atomicrmw(op, ptr, val, ordering, singlethread)
    end
    ```


    ```
    ; Function Attrs: uwtable
    define internal i32 @"*Atomic(Int32)@Atomic(T)#swap<Int32>:Int32"(%"Atomic(Int32)"* %self, i32 %value) #0 !dbg !2689 {
    entry:
    %0 = getelementptr inbounds %"Atomic(Int32)", %"Atomic(Int32)"* %self, i32 0, i32 0, !dbg !2690
    %1 = load i32, i32* %0, align 4, !dbg !2690
    br label %atomicrmw.start, !dbg !2690
    atomicrmw.start: ; preds = %atomicrmw.start, %entry
    %loaded = phi i32 [ %1, %entry ], [ %newloaded, %atomicrmw.start ], !dbg !2690
    %2 = cmpxchg i32* %0, i32 %loaded, i32 %value seq_cst seq_cst, align 4, !dbg !2690
    %success = extractvalue { i32, i1 } %2, 1, !dbg !2690
    %newloaded = extractvalue { i32, i1 } %2, 0, !dbg !2690
    br i1 %success, label %atomicrmw.end, label %atomicrmw.start, !dbg !2690
    atomicrmw.end: ; preds = %atomicrmw.start
    ret i32 %newloaded, !dbg !2690
    }
    ```

    ```
    .p2align 2 ; -- Begin function *Atomic(Int32)@Atomic(T)#swap<Int32>:Int32
    "_*Atomic(Int32)@Atomic(T)#swap<Int32>:Int32": ; @"*Atomic(Int32)@Atomic(T)#swap<Int32>:Int32"
    Lfunc_begin491:
    .loc 68 161 0 ; atomic.cr:161:0
    .cfi_startproc
    ; %bb.0: ; %entry
    stp x29, x30, [sp, #-16]! ; 16-byte Folded Spill
    mov x29, sp
    .cfi_def_cfa w29, 16
    .cfi_offset w30, -8
    .cfi_offset w29, -16
    Ltmp1981:
    .loc 68 161 3 prologue_end ; atomic.cr:161:3
    ldr w8, [x0]
    b LBB491_2
    LBB491_1: ; %cmpxchg.nostore
    ; in Loop: Header=BB491_2 Depth=1
    .loc 68 0 3 is_stmt 0 ; atomic.cr:0:3
    mov w9, wzr
    .loc 68 161 3 ; atomic.cr:161:3
    clrex
    cbnz w9, LBB491_6
    LBB491_2: ; %atomicrmw.start
    ; =>This Loop Header: Depth=1
    ; Child Loop BB491_3 Depth 2
    mov w9, w8
    LBB491_3: ; %cmpxchg.start
    ; Parent Loop BB491_2 Depth=1
    ; => This Inner Loop Header: Depth=2
    ldaxr w8, [x0]
    cmp w8, w9
    b.ne LBB491_1
    ; %bb.4: ; %cmpxchg.trystore
    ; in Loop: Header=BB491_3 Depth=2
    stlxr w10, w1, [x0]
    cbnz w10, LBB491_3
    ; %bb.5: ; in Loop: Header=BB491_2 Depth=1
    .loc 68 0 3 ; atomic.cr:0:3
    mov w9, #1
    .loc 68 161 3 ; atomic.cr:161:3
    cbz w9, LBB491_2
    LBB491_6: ; %atomicrmw.end
    mov w0, w8
    ldp x29, x30, [sp], #16 ; 16-byte Folded Reload
    ret
    Ltmp1982:
    Lfunc_end491:
    .cfi_endproc
    ; -- End function
    ```