Only allocate the minimal alignment requested for a type when possible. #1604
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srosefield-riverside
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swasey
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Nov 12, 2025
| }); | ||
| Pointer::stack_slot(stack_slot) | ||
| } else { | ||
| // Alignment is too big to handle using the above hack. Dynamically realign a stack slot |
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Please adjust this comment. IIUC, you're getting rid of the "hack".
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Dynamic realignment is still necessary when align > abi_align due to Cranelift limitations.
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I meant "the hack above" no longer refers to the old code's size/abi_align*abi_align.
bjorn3
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Nov 15, 2025
| size.is_multiple_of(align), | ||
| "size must be a multiple of alignment (size={size}, align={align})" | ||
| ); | ||
| assert!(align.is_power_of_two(), "alignment must be a power of two (align={align})"); |
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This can be a debug assert. Unlike the above assertion, I don't see it very likely that it will fail even while actively making changes to cg_clif.
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Cranelift now supports explicit alignment for stack slots so we can allocate the requested type alignment when it can be guaranteed by the target.