Register Usage - RTL Expression

[Ian Lance Taylor]

"Rohit Arul Raj" <rohitarulraj@gmail.com> writes:

> 1. How does the life1 pass gets the register usage information from
> the gcse pass?

The GCSE pass does not generate any register usage informatoin.  The
life1 pass computes register usage by looking at the RTL.

> 2. From which other passes and how, the information about registers
> used can be determined by looking at the RTL dump of the corresponding
> pass?

You can always determine register usage by simply looking at the RTL
and seeing which registers it uses.  There are a couple of special
cases relating to exception handling.

> 3. Any documentation regarding the above?

Not in any one place.

Ian