[Bug middle-end/99299] Need a recoverable version of __builtin_trap()

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=99299

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

           What    |Removed                     |Added
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           Keywords|                            |missed-optimization
                 CC|                            |rguenth at gcc dot gnu.org

--- Comment #4 from Richard Biener <rguenth at gcc dot gnu.org> ---
'enhancement' Importance is the magic we use, in the end it's a missed
optimization since you refer to sub-optimal code gen.

I'm not sure what your proposed not noreturn trap() would do in terms of
IL semantics compared to a not specially annotated general call?

"recoverable" likely means resuming after the trap, not on an exception
path (so it'll not be a throw())?

The only thing that might be useful to the middle-end would be marking
the function as not altering the memory state.  But I suppose it should
still serve as a barrier for code motion of both loads and stores, even
of those loads/stores are known to not trap.  The only magic we'd have
for this would be __attribute__((const,returns_twice)).  Which likely
will be more detrimental to general optimization.

So - what's the "sub-optimal code generation" you refer to from the
(presumably) volatile asm() you use for the trap?

[yeah, asm() on GIMPLE is less optimized than a call]