cmd/compile: remove -d=typecheckinl flag

This flag forced the compiler to eagerly type check all available
inline function bodies, which presumably was useful in the early days
of implementing inlining support. However, it shouldn't have any
significance with the unified frontend, since the same code paths are
used for constructing normal function bodies as for inlining.

Updates #57410.

Change-Id: I6842cf86bcd0fbf22ac336f2fc0b7b8fe14bccca
Reviewed-on: https://go-review.googlesource.com/c/go/+/458617
Reviewed-by: Keith Randall <khr@golang.org>
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
Reviewed-by: Keith Randall <khr@google.com>
Auto-Submit: Matthew Dempsky <mdempsky@google.com>
TryBot-Result: Gopher Robot <gobot@golang.org>

src/cmd/compile/internal/base/debug.go

@@ -46,7 +46,6 @@ type DebugFlags struct {
 	SoftFloat             int    `help:"force compiler to emit soft-float code" concurrent:"ok"`
 	SyncFrames            int    `help:"how many writer stack frames to include at sync points in unified export data"`
 	TypeAssert            int    `help:"print information about type assertion inlining"`
-	TypecheckInl          int    `help:"eager typechecking of inline function bodies" concurrent:"ok"`
 	WB                    int    `help:"print information about write barriers"`
 	ABIWrap               int    `help:"print information about ABI wrapper generation"`
 	MayMoreStack          string `help:"call named function before all stack growth checks" concurrent:"ok"`

src/cmd/compile/internal/gc/main.go

@@ -250,12 +250,6 @@ func Main(archInit func(*ssagen.ArchInfo)) {
 	}
 	typecheck.IncrementalAddrtaken = true
 
-	if base.Debug.TypecheckInl != 0 {
-		// Typecheck imported function bodies if Debug.l > 1,
-		// otherwise lazily when used or re-exported.
-		typecheck.AllImportedBodies()
-	}
-
 	// Read profile file and build profile-graph and weighted-call-graph.
 	base.Timer.Start("fe", "pgoprofile")
 	var profile *pgo.Profile

src/cmd/compile/internal/inline/inl.go

@@ -1096,10 +1096,6 @@ func CalleeEffects(init *ir.Nodes, callee ir.Node) {
 // the inlining tree position index, for use with src.NewInliningBase
 // when rewriting positions.
 func oldInlineCall(call *ir.CallExpr, fn *ir.Func, inlIndex int) *ir.InlinedCallExpr {
-	if base.Debug.TypecheckInl == 0 {
-		typecheck.ImportedBody(fn)
-	}
-
 	SSADumpInline(fn)
 
 	ninit := call.Init()