[Bug c++/80613] [8 Regression] ICE in is_gimple_reg_type with -O2

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=80613

--- Comment #6 from Richard Biener <rguenth at gcc dot gnu.org> ---
Hmm, cddce leaves us with free (_11) and the def of _11 removed.  _11 was

Deleting LHS of call: _11 = strdup (&d);

so caused by

2017-04-29  Prathamesh Kulkarni  <prathamesh.kulka...@linaro.org>

        PR tree-optimization/79697
        * tree-ssa-dce.c (mark_stmt_if_obviously_necessary): Check if callee
        is BUILT_IN_STRDUP, BUILT_IN_STRNDUP, BUILT_IN_REALLOC.
        (propagate_necessity): Check if def_callee is BUILT_IN_STRDUP or
        BUILT_IN_STRNDUP.
        * gimple-fold.c (gimple_fold_builtin_realloc): New function.
        (gimple_fold_builtin): Call gimple_fold_builtin_realloc.

which failed to update BUILT_IN_FREE handling properly.