On 29 October 2010 00:06, Joern Rennecke <joern.renne...@embecosm.com> wrote: > Quoting Mohamed Shafi <shafi...@gmail.com>: > >> Hi, >> >> I am doing a port in GCC 4.5.1. For the port >> >> 1. there is only (reg + offset) addressing mode only when reg is SP. >> Other base registers are not allowed >> 2. FP cannot be used as a base register. (FP based addressing is done >> by copying it into a base register) >> In order to take advantage of FP elimination (this will create SP + >> offset addressing), what i did the following >> >> 1. Created a new register class (address registers + FP) and used this >> new class as the BASE_REG_CLASS > > Stop right there. You need to distinguish between FRAME_POINTER_REGNUM > and HARD_FRAME_POINTER_REGNUM. >
From the description given in the internals, i am not able to understand why you suggested this. Could you please explain this? Shafi
