cmd/compile: fix failure to communicate between ABIinfo producer&consumer

ABI info producer and consumer had different ideas for register
order for parameters.

Includes a test, includes improvements to debugging output.

Updates #44816.

Change-Id: I4812976f7a6c08d6fc02aac1ec0544b1f141cca6
Reviewed-on: https://go-review.googlesource.com/c/go/+/299570
Trust: David Chase <drchase@google.com>
Reviewed-by: Than McIntosh <thanm@google.com>

1 files changed, 37 insertions, 0 deletions

diff --git a/test/abi/s_sif_sif.go b/test/abi/s_sif_sif.go
new file mode 100644
index 0000000000..f05f26f29f
--- /dev/null
+++ b/test/abi/s_sif_sif.go
@@ -0,0 +1,37 @@
+// run
+
+//go:build !wasm
+// +build !wasm
+
+// Copyright 2021 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
+
+// Test ensures that abi information producer and consumer agree about the
+// order of registers for inputs.  T's registers should be I0, F0, I1, F1.
+
+import "fmt"
+
+type P struct {
+	a int8
+	x float64
+}
+
+type T struct {
+	d, e P
+}
+
+//go:registerparams
+//go:noinline
+func G(t T) float64 {
+	return float64(t.d.a+t.e.a) + t.d.x + t.e.x
+}
+
+func main() {
+	x := G(T{P{10, 20}, P{30, 40}})
+	if x != 100.0 {
+		fmt.Printf("FAIL, Expected 100, got %f\n", x)
+	}
+}