cmd/compile: preserve name association when eliding copies in expand_calls
If v is a Copy of x, we will rewrite v to x. If v has a name
associated to it, let the name associate to x.
Under register ABI, this helps associate in-register Arg values
to the parameters' names. (But does not address all cases.)
Change-Id: I47c779e56c9d0823a88890497e32326bc0290f82
Reviewed-on: https://go-review.googlesource.com/c/go/+/309330
Trust: Cherry Zhang <cherryyz@google.com>
Run-TryBot: Cherry Zhang <cherryyz@google.com>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: David Chase <drchase@google.com>
Reviewed-by: Than McIntosh <thanm@google.com>
diff --git a/src/cmd/compile/internal/ssa/expand_calls.go b/src/cmd/compile/internal/ssa/expand_calls.go
index cb8b2ee..d947443 100644
--- a/src/cmd/compile/internal/ssa/expand_calls.go
+++ b/src/cmd/compile/internal/ssa/expand_calls.go
@@ -1449,6 +1449,19 @@
}
// Step 6: elide any copies introduced.
+ // Update named values.
+ for _, name := range f.Names {
+ values := f.NamedValues[name]
+ for i, v := range values {
+ if v.Op == OpCopy {
+ a := v.Args[0]
+ for a.Op == OpCopy {
+ a = a.Args[0]
+ }
+ values[i] = a
+ }
+ }
+ }
for _, b := range f.Blocks {
for _, v := range b.Values {
for i, a := range v.Args {
