On Thu, Jul 16, 2015 at 11:21:25AM +0100, Jiong Wang wrote: > > Jeff Law writes: > > > On 06/23/2015 02:29 AM, Ramana Radhakrishnan wrote: > > > >>> If you try disabling the REG_EQUAL note generation [*], you'll probably > >>> find a > >>> performance regression on arm32 (and probably on aarch64 as well? > >>> we only > >> > >> IMHO disabling the REG_EQUAL note generation is the wrong way to go about > >> this. > > Agreed. > > > >> Irrespective of combine, as a first step we should fix the predicates > >> and the call expanders to prevent this sort of replacement in the > >> backends. Tightening the predicates in the call patterns will achieve > >> the same for you and then we can investigate the use of GOT_PREL. My > >> recollection of this is that you need to work out when it's more > >> beneficial to use GOT_PREL over GOT but it's been a while since I > >> looked in that area. > > Also agreed. This is primarily a backend issue with the call patterns. > > > > This is similar to the situation on the PA with the 32bit SOM runtime > > where direct and indirect calls have different calling conventions. > > Those different calling conventions combined with the early loading of > > the parameter registers in effect restricts us from being able to > > transform an indirect call into a direct call (combine) or vice-versa (cse). > > > > The way we handled this was to split the calls into two patterns, one > > for direct one for indirect and tightening their predicates appropriately. > > > > Jeff > > Attachment is the patch which repair -fno-plt support for AArch64. > > aarch64_is_noplt_call_p will only be true if: > > * gcc is generating position independent code. > * function symbol has declaration. > * either -fno-plt or "(no_plt)" attribute specified. > * it's a external function. > > OK for trunk?
OK. Thanks, James > > 2015-07-16 Jiong Wang <jiong.w...@arm.com> > > gcc/ > * config/aarch64/aarch64-protos.h (aarch64_is_noplt_call_p): New > declaration. > * config/aarch64/aarch64.c (aarch64_is_noplt_call_p): New function. > * config/aarch64/aarch64.md (call_value_symbol): Check noplt > scenarios. > (call_symbol): Ditto. > > gcc/testsuite/ > * gcc.target/aarch64/noplt_1.c: New testcase. > * gcc.target/aarch64/noplt_2.c: Ditto. > ((Though do check the ChangeLog formatting when you commit :-).))
