[PATCH] D114895: [SelectionDagBuilder] improve CallBrInst BlockAddress constraint handling

[Bill Wendling via Phabricator via llvm-commits]

void added a comment.

In D114895#3170282 <https://reviews.llvm.org/D114895#3170282>, @nickdesaulniers wrote:

> Shower-epiphany: we just need to walk the arg_list in reverse until we find the first `blockaddress` input; the number of non-`blockaddress` inputs is the amount we must bias the index calculation to find the right block address.
>
> Unless you can tie a block address. Hopefully `"+r"(&&goto_label)` isn't a valid output constraint...
>
>   void x(void) {
>       asm goto ("":"+r"(&&foo):::foo);
>       //                ^ error: lvalue required in 'asm' statement
>       foo:;
>   }
>
> oh thank god! ok then I can probably make that work.  Nonsensical rambling/notes below:

I would have had to give up programming and become a basket weaver if block addresses were l-values. :-P


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