[release-branch.go1.17] 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 #53470

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>
(cherry picked from commit c2d373d5d1802d7479f3c81dcf01d41bef3646dd)
Reviewed-on: https://go-review.googlesource.com/c/go/+/413456
Reviewed-by: Carlos Amedee <carlos@golang.org>

4 files changed, 18 insertions, 0 deletions

diff --git a/src/cmd/compile/internal/amd64/ssa.go b/src/cmd/compile/internal/amd64/ssa.go
index ca5f36e775..52f4937d04 100644
--- a/src/cmd/compile/internal/amd64/ssa.go
+++ b/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))
diff --git a/src/cmd/compile/internal/dwarfgen/dwarf.go b/src/cmd/compile/internal/dwarfgen/dwarf.go
index 0e22b61bc3..3ecadb9b9d 100644
--- a/src/cmd/compile/internal/dwarfgen/dwarf.go
+++ b/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()))
 		}
 	}
diff --git a/src/cmd/compile/internal/types/size.go b/src/cmd/compile/internal/types/size.go
index f0e695ab96..f2c23887f9 100644
--- a/src/cmd/compile/internal/types/size.go
+++ b/src/cmd/compile/internal/types/size.go
@@ -625,6 +625,12 @@ func PtrDataSize(t *Type) int64 {
 		}
 		return lastPtrField.Offset + PtrDataSize(lastPtrField.Type)
 
+	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
diff --git a/src/cmd/compile/internal/types/type.go b/src/cmd/compile/internal/types/type.go
index 1a9aa6916a..15d40e753f 100644
--- a/src/cmd/compile/internal/types/type.go
+++ b/src/cmd/compile/internal/types/type.go
@@ -1661,6 +1661,11 @@ 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