[LLVMdev] Reference Manual Clarifications 2

Jonathan S. Shapiro shap at eros-os.com
Tue Apr 1 06:55:08 PDT 2008

On Mon, 2008-03-31 at 20:59 -0700, Jon Sargeant wrote:
> The manual needs to state the rounding mode of the fptrunc, uitofp, and 
> sitofp instruction (if only to say it's undefined).  I recommend 
> round-to-nearest.

Alternatively, the manual needs to admit the notion of rounding mode
controls per IEEE floating point, and then define the instructions to
operate according to IEEE.

> What is the behavior of alloca if there is insufficient memory?  null or 
> undefined behavior?

While you are touching alloca docs, I had a discussion on IRC about it
that should be added: alloca allocates storage from the stack, and is
guaranteed not to trigger GC.

This matters because on some systems the stack frames might be allocated
from the heap. The alloca primitive assumes that this is not the case.

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