cmd/compile: expand calls cleanup

Convert expand calls into a smaller number of focused
recursive rewrites, and rely on an enhanced version of
"decompose" to clean up afterwards.

Debugging information seems to emerge intact.

Change-Id: Ic46da4207e3a4da5c8e2c47b637b0e35abbe56bb
Reviewed-on: https://go-review.googlesource.com/c/go/+/507295
Run-TryBot: David Chase <drchase@google.com>
Reviewed-by: Cherry Mui <cherryyz@google.com>
Reviewed-by: Keith Randall <khr@golang.org>
TryBot-Result: Gopher Robot <gobot@golang.org>

2 files changed, 42 insertions, 6 deletions

diff --git a/test/abi/more_intstar_input.go b/test/abi/more_intstar_input.go
index f0a48fbdc2..3eb0fbcc3d 100644
--- a/test/abi/more_intstar_input.go
+++ b/test/abi/more_intstar_input.go
@@ -12,10 +12,6 @@
 
 package main
 
-import (
-	"fmt"
-)
-
 var sink int
 
 //go:registerparams
@@ -33,12 +29,12 @@ func G(a, b, c, d, e, f, g, h, i, j, k, l, m *int) {
 	var scratch [1000 * 100]int
 	I := *c - *e - *l // zero.
 	scratch[I] = *d
-	fmt.Println("Got this far!")
+	println("Got this far!")
 	sink += scratch[0]
 }
 
 func main() {
 	a, b, c, d, e, f, g, h, i, j, k, l, m := 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13
 	F(&a, &b, &c, &d, &e, &f, &g, &h, &i, &j, &k, &l, &m)
-	fmt.Printf("Sink = %d\n", sink-7)
+	println("Sink =", sink-7)
 }
diff --git a/test/abi/reg_not_ssa.go b/test/abi/reg_not_ssa.go
new file mode 100644
index 0000000000..5bd4b51a6b
--- /dev/null
+++ b/test/abi/reg_not_ssa.go
@@ -0,0 +1,40 @@
+// run
+
+//go:build !wasm
+// +build !wasm
+
+// Copyright 2023 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package main
+
+// small enough for registers, too large for SSA
+type T struct {
+	a, b, c, d, e int
+}
+
+//go:noinline
+func F() {
+	a, b := g(), g()
+	h(b, b)
+	h(a, g())
+	if a.a == 1 {
+		a = g()
+	}
+	h(a, a)
+}
+
+//go:noinline
+func g() T {
+	return T{1, 2, 3, 4, 5}
+}
+
+//go:noinline
+func h(s, t T) {
+	if s != t {
+		println("NEQ")
+	}
+}
+
+func main() { F() }