[Bug bootstrap/91580] [10 Regression] i686-{darwin, linux} bootstrap fails after r274926

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=91580

Richard Biener <rguenth at gcc dot gnu.org> changed:

           What    |Removed                     |Added
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  Attachment #46777|0                           |1
        is obsolete|                            |

--- Comment #10 from Richard Biener <rguenth at gcc dot gnu.org> ---
Created attachment 46778
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=46778&action=edit
untested patch

Added missing df_insn_rescan, also if there is more than one reaching def for
the use we cannot simply replace it but we have to reset it (since we cannot
emit the "merge" copy).  Not sure if we could emit a duplicate debug-insn
and if that would help (maybe in the even RA assigns the same reg which is
unlikely since we want xmm regs here).