[LLVMdev] Generating Floating point constants

Eli Friedman eli.friedman at gmail.com
Wed Jun 2 03:21:02 PDT 2010

On Wed, Jun 2, 2010 at 2:59 AM, Stéphane Letz <letz at free.fr> wrote:
> Hi,
> We need to generate "Floating point constants" in our code. In http://llvm.org/docs/LangRef.html it is explained that FP has to follow special encoding rules to be handled by LLVM later one (hexadecimal coding...)
> Is there any code available in LLVM  to handle this kind of "standard float to LLVM float" conversion?

If you're writing C++ code, just stick your float into an APFloat and
doesn't worry about the hexadecimal coding.  If you're generating
textual IR, and you don't care about the precise hexadecimal
representation, AFAIK just printing a decimal float works.  If you
really want a hexadecimal encoding, just reinterpret the
floating-point number as an integer and print in hexadecimal; an "LLVM
float" is just an IEEE float printed in hexadecimal.


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