On 03/23/2011 04:03 PM, Jeff Law wrote: > On 03/23/11 08:55, Bernd Schmidt wrote: >> The first basic block contains insns to move incoming argument registers >> to pseudos. When these pseudos live across calls, they get allocated to >> call-saved registers. This in turns disables shrink-wrapping, since the >> move instruction requires the prologue (saving the call-saved reg) to >> occur before it. > >> This patch addresses the problem by moving such moves downwards through >> the CFG until we find a place where the destination is used or the >> incoming argument is clobbered. > FWIW, downward motion of the moves out of arg registers (or loads from > arg slots) is definitely a good thing. This was a regular source of > unnecessary register pressure leading to spills in codes I've looked at. > > I hope your sinking code works better than the quick and dirty one I > wrote but never contributed.
Sadly I'm doing it after register allocation, so it wouldn't help with your problem. Bernd
