[Issue 17220] invalid code with -m32 -inline and struct that's size_t.sizeof x the size of an assigned enum value

[via Digitalmars-d-bugs]

https://issues.dlang.org/show_bug.cgi?id=17220

--- Comment #5 from github-bugzi...@puremagic.com ---
Commit pushed to newCTFE at https://github.com/dlang/dmd

https://github.com/dlang/dmd/commit/3dc0fa957ef362ba42779e3dd953931f9a908f45
workaround Issue #17220

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[Issue 17220] invalid code with -m32 -inline and struct that's size_t.sizeof x the size of an assigned enum value

[via Digitalmars-d-bugs]

https://issues.dlang.org/show_bug.cgi?id=17220

Martin Nowak  changed:

   What|Removed |Added

 Status|NEW |RESOLVED
 Resolution|--- |FIXED

--- Comment #4 from Martin Nowak  ---
This got accidentally fixed by
https://github.com/dlang/dmd/pull/6410/files#diff-0630e1297bdecef97aded9af2ddb879cL4041.

Seems like the problem was indeed a CSE which caused that no code was generated
for `mov cl, 8`, but the following `gen1(c3, 0xF3)` didn't deal with c3 being
CNIL, hence the code wasn't appended/emitted.

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[Issue 17220] invalid code with -m32 -inline and struct that's size_t.sizeof x the size of an assigned enum value

[via Digitalmars-d-bugs]

https://issues.dlang.org/show_bug.cgi?id=17220

--- Comment #3 from Martin Nowak  ---
The cmp runs on the `lhs` symbol, while only the `val` symbol get's
initialized.
Not sure, but seems like the copy got elided.

Here is the assembly for when the size of BCValue != size_t.sizeof *
BCTypeEnum.i32

mov cl, 8   ; 0018 _ B1, 08
mov byte ptr [rbp-78H], cl  ; 001A _ 88. 4D, 88
lea rsi, [rbp-78H]  ; 001D _ 48: 8D. 75, 88
lea rdi, [rbp-38H]  ; 0021 _ 48: 8D. 7D, C8
mov cl, 7   ; 0025 _ B1, 07
rep movsq   ; 0027 _ F3 48: A5
cmp byte ptr [rbp-38H], 8   ; 002A _ 80. 7D, C8, 08
jz  ?_003   ; 002E _ 74, 0A

Apparently the `mov cl, 8` instruction is a CSE in the bug case, no idea why
the rep movsq get's omitted b/c of that though.

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[Issue 17220] invalid code with -m32 -inline and struct that's size_t.sizeof x the size of an assigned enum value

[via Digitalmars-d-bugs]

https://issues.dlang.org/show_bug.cgi?id=17220

Martin Nowak  changed:

   What|Removed |Added

   Hardware|x86_64  |All
Summary|invalid code with -m32  |invalid code with -m32
   |-inline and struct that's   |-inline and struct that's
   |4x the size of an assigned  |size_t.sizeof x the size of
   |enum value  |an assigned enum value
 OS|All |Linux

--- Comment #2 from Martin Nowak  ---
Ah thanks for size_t.sizeof times enum value finding.
This is easily the weirdest backend bug I've seen so far.

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