with P9 Model
Enable the pre-ra and post-ra scheduler strategy for Power10 as we want
to customize the heuristic later. And switch the scheduler model with P9
model before P10 Model is available. The NoSchedModel is modelled as
in-order cpu and the pre-ra scheduler is not bi-directional which will
have big impact on the scheduler.
Reviewed By: jji
Differential Revision: https://reviews.llvm.org/D86865
A linker optimization is available on PowerPC for GOT indirect PCRelative loads.
The idea is that we can mark a usual GOT indirect load:
pld 3, vec@got@pcrel(0), 1
lwa 3, 4(3)
With a relocation to say that if we don't need to go through the GOT we can let
the linker further optimize this and replace a load with a nop.
pld 3, vec@got@pcrel(0), 1
.Lpcrel1:
.reloc .Lpcrel1-8,R_PPC64_PCREL_OPT,.-(.Lpcrel1-8)
lwa 3, 4(3)
This patch adds the logic that allows the compiler to add the R_PPC64_PCREL_OPT.
Reviewers: nemanjai, lei, hfinkel, sfertile, efriedma, tstellar, grosbach
Reviewed By: nemanjai
Differential Revision: https://reviews.llvm.org/D79864
Tail Calls were initially disabled for PC Relative code because it was not safe
to make certain assumptions about the tail calls (namely that all compiled
functions no longer used the TOC pointer in R2). However, once all of the
TOC pointer references have been removed it is safe to tail call everything
that was tail called prior to the PC relative additions as well as a number of
new cases.
For example, it is now possible to tail call indirect functions as there is no
need to save and restore the TOC pointer for indirect functions if the caller
is marked as may clobber R2 (st_other=1). For the same reason it is now also
possible to tail call functions that are external.
Differential Revision: https://reviews.llvm.org/D77788
Fangrui Song