cmd/compile: allow 128-bit values to be spilled

We sometimes use 16-byte load+store to move values around in memory.
In rare circumstances, the loaded value must be spilled because the
store can't happen yet.

In that case, we need to be able to spill the 16-byte value.

Fixes #53454

Change-Id: I09fd08e11a63c6ba3ef781d3f5ede237e9b0132e
Reviewed-on: https://go-review.googlesource.com/c/go/+/413294
Reviewed-by: Keith Randall <khr@golang.org>
TryBot-Result: Gopher Robot <gobot@golang.org>
Reviewed-by: David Chase <drchase@google.com>
Run-TryBot: Keith Randall <khr@golang.org>
Reviewed-by: Keith Randall <khr@google.com>

src/cmd/compile/internal/amd64/ssa.go

@@ -78,6 +78,8 @@ func storeByType(t *types.Type) obj.As {
 			return x86.AMOVL
 		case 8:
 			return x86.AMOVQ
+		case 16:
+			return x86.AMOVUPS
 		}
 	}
 	panic(fmt.Sprintf("bad store type %v", t))

src/cmd/compile/internal/dwarfgen/dwarf.go

@@ -91,6 +91,11 @@ func Info(fnsym *obj.LSym, infosym *obj.LSym, curfn interface{}) ([]dwarf.Scope,
 				continue
 			}
 			apdecls = append(apdecls, n)
+			if n.Type().Kind() == types.TSSA {
+				// Can happen for TypeInt128 types. This only happens for
+				// spill locations, so not a huge deal.
+				continue
+			}
 			fnsym.Func().RecordAutoType(reflectdata.TypeLinksym(n.Type()))
 		}
 	}

src/cmd/compile/internal/types/size.go

@@ -590,6 +590,12 @@ func PtrDataSize(t *Type) int64 {
 		}
 		return 0
 
+	case TSSA:
+		if t != TypeInt128 {
+			base.Fatalf("PtrDataSize: unexpected ssa type %v", t)
+		}
+		return 0
+
 	default:
 		base.Fatalf("PtrDataSize: unexpected type, %v", t)
 		return 0

src/cmd/compile/internal/types/type.go

@@ -1705,6 +1705,11 @@ var (
 	TypeResultMem = newResults([]*Type{TypeMem})
 )
 
+func init() {
+	TypeInt128.width = 16
+	TypeInt128.align = 8
+}
+
 // NewNamed returns a new named type for the given type name. obj should be an
 // ir.Name. The new type is incomplete (marked as TFORW kind), and the underlying
 // type should be set later via SetUnderlying(). References to the type are

test/fixedbugs/issue53454.go

@@ -0,0 +1,89 @@
+// compile
+
+// Copyright 2022 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
+
+type T1 struct {
+	A T5
+	B T2
+	C T7
+	D T4
+}
+
+type T2 struct {
+	T3
+	A float64
+	E float64
+	C float64
+}
+
+type T3 struct {
+	F float64
+	G float64
+	H float64
+	I float64
+	J float64
+	K float64
+	L float64
+}
+
+type T4 struct {
+	M float64
+	N float64
+	O float64
+	P float64
+}
+
+type T5 struct {
+	Q float64
+	R float64
+	S float64
+	T float64
+	U float64
+	V float64
+}
+
+type T6 struct {
+	T9
+	C T10
+}
+
+type T7 struct {
+	T10
+	T11
+}
+
+type T8 struct {
+	T9
+	C T7
+}
+
+type T9 struct {
+	A T5
+	B T3
+	D T4
+}
+
+type T10 struct {
+	W float64
+}
+
+type T11 struct {
+	X float64
+	Y float64
+}
+
+func MainTest(x T1, y T8, z T6) float64 {
+	return Test(x.B, x.A, x.D, x.C, y.B, y.A, y.D, y.C, z.B, z.A, z.D,
+		T7{
+			T10: T10{
+				W: z.C.W,
+			},
+			T11: T11{},
+		},
+	)
+}
+func Test(a T2, b T5, c T4, d T7, e T3, f T5, g T4, h T7, i T3, j T5, k T4, l T7) float64