[Bug debug/90273] [9/10 Regression] GCC runs out of memory building Firefox

[rsandifo at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=90273

rsandifo at gcc dot gnu.org <rsandifo at gcc dot gnu.org> changed:

           What    |Removed                     |Added
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                 CC|                            |rsandifo at gcc dot gnu.org

--- Comment #17 from rsandifo at gcc dot gnu.org <rsandifo at gcc dot gnu.org> ---
Created attachment 46261
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=46261&action=edit
Doing the removal in find_obviously_necessary_stmts

Just for the record: I'd written this over the weekend for completely unrelated
reasons (was looking at debug info, and wanted to replicate the DCE that is
already done in RTL).  It doesn't include the DEBUG_EXPR_DECL stuff, so
obviously can't go in as-is, but it means that we never even add the redundant
instructions to the worklist.