Avoid unnecessary temporaries when ref'ing a DST value #28787
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r? @pcwalton (rust_highfive has picked a reviewer for you, use r? to override) |
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r? @eddyb |
| @@ -1709,8 +1699,11 @@ fn trans_addr_of<'blk, 'tcx>(bcx: Block<'blk, 'tcx>, | |||
| let mut bcx = bcx; | |||
| let sub_datum = unpack_datum!(bcx, trans_to_lvalue(bcx, subexpr, "addr_of")); | |||
| if !type_is_sized(bcx.tcx(), sub_datum.ty) { | |||
| // DST lvalue, close to a fat pointer | |||
| ref_fat_ptr(bcx, sub_datum) | |||
| let dest_ty = bcx.tcx().mk_imm_ref(bcx.tcx().mk_region(ty::ReStatic), sub_datum.ty); | |||
A DST value and a fat pointer to it have the same representation, all we have to do is to adjust the type of the datum holding the pointer.
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@bors r+ |
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📌 Commit bda083f has been approved by |
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A DST value and a fat pointer to it have the same representation, all we have to do is to adjust the type of the datum holding the pointer.
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Codegen improvements. Any numbers? |
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Pretty negligible as far as optimized builds are concerned AFAICT. Didn't
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A DST value and a fat pointer to it have the same representation, all we
have to do is to adjust the type of the datum holding the pointer.