cmd/compile: fix naming of decomposed structs

When a struct is SSAable, we will name its component parts
by their field names.  For example,
type T struct {
     a, b, c int
}
If we ever need to spill a variable x of type T, we will
spill its individual components to variables named x.a, x.b,
and x.c.

Change-Id: I857286ff1f2597f2c4bbd7b4c0b936386fb37131
Reviewed-on: https://go-review.googlesource.com/21389
Reviewed-by: David Chase <drchase@google.com>

1 files changed, 3 insertions, 0 deletions

diff --git a/src/cmd/compile/internal/ssa/export_test.go b/src/cmd/compile/internal/ssa/export_test.go
index ce577ef055..0a67de9f05 100644
--- a/src/cmd/compile/internal/ssa/export_test.go
+++ b/src/cmd/compile/internal/ssa/export_test.go
@@ -48,6 +48,9 @@ func (d DummyFrontend) SplitComplex(s LocalSlot) (LocalSlot, LocalSlot) {
 	}
 	return LocalSlot{s.N, d.TypeFloat32(), s.Off}, LocalSlot{s.N, d.TypeFloat32(), s.Off + 4}
 }
+func (d DummyFrontend) SplitStruct(s LocalSlot, i int) LocalSlot {
+	return LocalSlot{s.N, s.Type.FieldType(i), s.Off + s.Type.FieldOff(i)}
+}
 func (DummyFrontend) Line(line int32) string {
 	return "unknown.go:0"
 }