[LLVMdev] [llvm-commits] Branch Probability

[Duncan Sands]

Hi Andrew,

> Representation: 32-bit unsigned int stored in IR meta-data.

why store it in the IR, and not just have it be an analysis that you can query
for branch probabilities?  If you store it in the IR then it may well get out
of date (eg: when an optimizer realizes that some branches is dead and deletes
it, resulting in probabilities that don't add up to 1 on the other branches).
This happens all the time in GCC and is kind of annoying.

Ciao, Duncan.