Predictive commoning leads to register to register moves through memory.

Hello all, I've been looking at a code generation issue with GCC 5.2 lately dealing with register to register moves through memory with -O3 -funroll-loops. For reference the C code is at the end of this mail. The generated code for mips is (cut down for clarity, ldc1 and sdc1 are double word fl

RE: Predictive commoning leads to register to register moves through memory.

testing. Thanks, Simon -Original Message- From: Richard Biener [mailto:richard.guent...@gmail.com] Sent: 31 August 2015 11:40 To: Jeff Law Cc: Simon Dardis; gcc@gcc.gnu.org Subject: Re: Predictive commoning leads to register to register moves through memory. On Fri, Aug 28, 2015 at 5:48

RE: Predictive commoning leads to register to register moves through memory.

I took an attempt at addressing this through the RTL GCSE pass. This attempt tweaks mem_attrs_eq_p to return true if its comparing something like poly+8 and MEM [&poly + 8]. Is this a more suitable approach? Thanks, Simon +/* Return true if p and q reference the same location by the same name

RE: Predictive commoning leads to register to register moves through memory.

cases of base objects and the above mentioned addr_eq_p. Also in that patch is the change for mem_attrs_eq_p as in that case the offset is not part of the TREE expression, so it has to be handled differently. Thoughts? Thanks, Simon -Original Message- From: Richard Biener [mailto:richard.guen