cmd/compile: delay expansion of OpArg until expand_calls

As it says, delay expanpsion of OpArg to the expand_calls phase,
to enable (eventually) interprocedural SSA optimizations, and
(sooner) change to a register ABI.

Includes a round of cleanup to function names and comments,
largely to match the expanded scope of the functions.

This CL removes the per-function dependence on GOSSAHASH,
but the go116lateCallExpansion kill switch remains (and was
tested locally to ensure it worked).

Two functions in expand_calls.go that performed overlapping
things were combined into a single function that is called
twice.

Fixes #42236.
For #40724.

Change-Id: Icbb78947eaa39f17f2c1210d5c2caef20abd6571
Reviewed-on: https://go-review.googlesource.com/c/go/+/262117
Trust: David Chase <drchase@google.com>
Run-TryBot: David Chase <drchase@google.com>
Reviewed-by: Cherry Zhang <cherryyz@google.com>

1 files changed, 2 insertions, 2 deletions

diff --git a/src/cmd/compile/internal/ssa/config.go b/src/cmd/compile/internal/ssa/config.go
index cb6f6fe7a1..0fe0337ddf 100644
--- a/src/cmd/compile/internal/ssa/config.go
+++ b/src/cmd/compile/internal/ssa/config.go
@@ -199,9 +199,9 @@ const (
 const go116lateCallExpansion = true
 
 // LateCallExpansionEnabledWithin returns true if late call expansion should be tested
-// within compilation of a function/method triggered by GOSSAHASH (defaults to "yes").
+// within compilation of a function/method.
 func LateCallExpansionEnabledWithin(f *Func) bool {
-	return go116lateCallExpansion && f.DebugTest // Currently set up for GOSSAHASH bug searches
+	return go116lateCallExpansion
 }
 
 // NewConfig returns a new configuration object for the given architecture.