[PATCH] Return undef on conversions that overflow (PR21330).

Sanjay Patel spatel at rotateright.com
Fri Oct 3 09:35:30 PDT 2014

Hi asl, hfinkel, sylvestre.ledru,

The LLVM Lang Ref states for signed/unsigned int to float conversions:
"If the value cannot fit in the floating point value, the results are undefined."

And for FP to signed/unsigned int:
"If the value cannot fit in ty2, the results are undefined."

This matches the C definitions.

The existing behavior pins to infinity or a max int value, but that may just lead to more confusion as seen in:

Returning undef will hopefully lead to a less silent failure.


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