On Fri, May 29, 2015 at 11:14 PM, Pritam Gharat <pritam01gha...@gmail.com> wrote: > I am writing a Simple IPA Pass which is inserted after ipa-pta. This > pass identifies whether a chain of recurrence is built by gcc or not. > I have used tree_is_chrec(t) to check if t represents chain of > recurrence and function find_var_scev_info(bb, var) to obtain the > scev information generated (which comprises of chrec information). > However, find_var_scev_info() is a static function and cannot be > called from my plugin. find_var_scev_info is for internal use only. I think the proper interface is simple_iv. You may refer to other users of that interface in GCC. Also, please don't top-reply the message.
Thanks, bin > > Is there any alternative way to get the chain of recurrence > information? Or do we need to change the gcc source code by making the > function find_var_scev_info() non-static and recompiling the source > code? > > Thanks, > Pritam Gharat > > On Fri, May 29, 2015 at 10:34 AM, Bin.Cheng <amker.ch...@gmail.com> wrote: >> On Fri, May 29, 2015 at 12:41 PM, Pritam Gharat >> <pritam01gha...@gmail.com> wrote: >>> GCC builds a chain of recurrence to capture a pattern in which an >>> array is accessed in a loop. Is there any function which identifies >>> that gcc has built a chain of recurrence? Is this information >>> associated to the gimple assignment which accesses the array elements? >>> >> GCC analyzes evolution of scalar variables on SSA representation. >> Each ssa var is treated as unique and can be analyzed. If the address >> expression itself is a ssa var, it can be analyzed by scev; otherwise, >> the users of scev have to compute by themselves on the bases of other >> scev vars. For example, address of MEM[scev_var] can be analyzed by >> scev; while address of MEM[invariant_base+scev_iv] is computed by >> users. Well, at least this is how IVOPT works. You can refer to >> top-file comment in tree-scalar-evolution.c for detailed information. >> General routines for chain of recurrence is in file tree-chrec.c. >> >> Thanks, >> bin >>> >>> Thanks, >>> Pritam Gharat
