cmd: remove GOEXPERIMENT=nounified knob

This CL removes the GOEXPERIMENT=nounified knob, and any conditional
statements that depend on that knob. Further CLs to remove unreachable
code follow this one.

Updates #57410.

Change-Id: I39c147e1a83601c73f8316a001705778fee64a91
Reviewed-on: https://go-review.googlesource.com/c/go/+/458615
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
TryBot-Result: Gopher Robot <gobot@golang.org>
Reviewed-by: Cherry Mui <cherryyz@google.com>

1 files changed, 7 insertions, 52 deletions

diff --git a/src/cmd/compile/internal/inline/inl.go b/src/cmd/compile/internal/inline/inl.go
index e3b2e44f61..de25d451eb 100644
--- a/src/cmd/compile/internal/inline/inl.go
+++ b/src/cmd/compile/internal/inline/inl.go
@@ -645,15 +645,13 @@ func (v *hairyVisitor) doNode(n ir.Node) bool {
 		// minimize impact to the existing inlining heuristics (in
 		// particular, to avoid breaking the existing inlinability regress
 		// tests), we need to compensate for this here.
-		if base.Debug.Unified != 0 {
-			if init := n.Rhs[0].Init(); len(init) == 1 {
-				if _, ok := init[0].(*ir.AssignListStmt); ok {
-					// 4 for each value, because each temporary variable now
-					// appears 3 times (DCL, LHS, RHS), plus an extra DCL node.
-					//
-					// 1 for the extra "tmp1, tmp2 = f()" assignment statement.
-					v.budget += 4*int32(len(n.Lhs)) + 1
-				}
+		if init := n.Rhs[0].Init(); len(init) == 1 {
+			if _, ok := init[0].(*ir.AssignListStmt); ok {
+				// 4 for each value, because each temporary variable now
+				// appears 3 times (DCL, LHS, RHS), plus an extra DCL node.
+				//
+				// 1 for the extra "tmp1, tmp2 = f()" assignment statement.
+				v.budget += 4*int32(len(n.Lhs)) + 1
 			}
 		}
 
@@ -958,49 +956,6 @@ func mkinlcall(n *ir.CallExpr, fn *ir.Func, maxCost int32, inlCalls *[]*ir.Inlin
 		return n
 	}
 
-	// The non-unified frontend has issues with inlining and shape parameters.
-	if base.Debug.Unified == 0 {
-		// Don't inline a function fn that has no shape parameters, but is passed at
-		// least one shape arg. This means we must be inlining a non-generic function
-		// fn that was passed into a generic function, and can be called with a shape
-		// arg because it matches an appropriate type parameters. But fn may include
-		// an interface conversion (that may be applied to a shape arg) that was not
-		// apparent when we first created the instantiation of the generic function.
-		// We can't handle this if we actually do the inlining, since we want to know
-		// all interface conversions immediately after stenciling. So, we avoid
-		// inlining in this case, see issue #49309. (1)
-		//
-		// See discussion on go.dev/cl/406475 for more background.
-		if !fn.Type().Params().HasShape() {
-			for _, arg := range n.Args {
-				if arg.Type().HasShape() {
-					if logopt.Enabled() {
-						logopt.LogOpt(n.Pos(), "cannotInlineCall", "inline", ir.FuncName(ir.CurFunc),
-							fmt.Sprintf("inlining function %v has no-shape params with shape args", ir.FuncName(fn)))
-					}
-					return n
-				}
-			}
-		} else {
-			// Don't inline a function fn that has shape parameters, but is passed no shape arg.
-			// See comments (1) above, and issue #51909.
-			inlineable := len(n.Args) == 0 // Function has shape in type, with no arguments can always be inlined.
-			for _, arg := range n.Args {
-				if arg.Type().HasShape() {
-					inlineable = true
-					break
-				}
-			}
-			if !inlineable {
-				if logopt.Enabled() {
-					logopt.LogOpt(n.Pos(), "cannotInlineCall", "inline", ir.FuncName(ir.CurFunc),
-						fmt.Sprintf("inlining function %v has shape params with no-shape args", ir.FuncName(fn)))
-				}
-				return n
-			}
-		}
-	}
-
 	if base.Flag.Cfg.Instrumenting && types.IsRuntimePkg(fn.Sym().Pkg) {
 		// Runtime package must not be instrumented.
 		// Instrument skips runtime package. However, some runtime code can be