cmd/internal/obj/ppc64: cleanup and remove usage of getimpliedreg

getimpliedreg was used to set a default register in cases where
one was implied but not set by the assembler or compiler.

In most cases with constant values, R0 is implied, and is the value
0 by architectural design.  In those cases, R0 is always used, so
treat 0 and REG_R0 as interchangeable in those encodings.

Similarly, the pseudo-register SP or FP is used to in place of the
stack pointer, always R1 on PPC64. Unconditionally set this during
classification of NAME_AUTO and NAME_PARAM as it may be 0.

The case where REGSB might be returned from getimpliedreg is never
used. REGSB is aliased to R2, but in practice it is either R0 or R2
depending on buildmode. See symbolAccess in asm9.go for an example.

Change-Id: I7283e66d5351f56a7fe04cee38714910eaa73cb3
Reviewed-on: https://go-review.googlesource.com/c/go/+/434775
Reviewed-by: Lynn Boger <laboger@linux.vnet.ibm.com>
Reviewed-by: David Chase <drchase@google.com>
Run-TryBot: Paul Murphy <murp@ibm.com>
Reviewed-by: Than McIntosh <thanm@google.com>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
TryBot-Result: Gopher Robot <gobot@golang.org>

0 files changed, 0 insertions, 0 deletions