cmd/compile: do not write implicit conversion for append in Unified IR

Same as CL 418475, but for Unified IR. Updates #53888 Fixes #54337 Change-Id: I31d5a7af04d8e3902ed25db85009d46ea4c38dbe Reviewed-on: https://go-review.googlesource.com/c/go/+/422040 TryBot-Result: Gopher Robot <[email protected]> Reviewed-by: Matthew Dempsky <[email protected]> Run-TryBot: Cuong Manh Le <[email protected]> Reviewed-by: Than McIntosh <[email protected]>
golang · Aug 9, 2022 · 2699065 · 2699065
1 parent a292b39
commit 2699065
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Showing 2 changed files with 8 additions and 2 deletions.
diff --git a/src/cmd/compile/internal/noder/reader.go b/src/cmd/compile/internal/noder/reader.go
@@ -1989,6 +1989,13 @@ func (r *reader) expr() (res ir.Node) {
 		case ir.OAPPEND:
 			n := n.(*ir.CallExpr)
 			n.RType = r.rtype(pos)
+			// For append(a, b...), we don't need the implicit conversion. The typechecker already
+			// ensured that a and b are both slices with the same base type, or []byte and string.
+			if n.IsDDD {
+				if conv, ok := n.Args[1].(*ir.ConvExpr); ok && conv.Op() == ir.OCONVNOP && conv.Implicit() {
+					n.Args[1] = conv.X
+				}
+			}
 		case ir.OCOPY:
 			n := n.(*ir.BinaryExpr)
 			n.RType = r.rtype(pos)

diff --git a/src/cmd/compile/internal/test/issue53888_test.go b/src/cmd/compile/internal/test/issue53888_test.go
@@ -2,7 +2,7 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-//go:build !race && !goexperiment.unified
+//go:build !race
 
 package test
 
@@ -11,7 +11,6 @@ import (
 	"testing"
 )
 
-// TODO(cuonglm,mdempsky): figure out why Unifed IR failed?
 func TestAppendOfMake(t *testing.T) {
 	testenv.SkipIfOptimizationOff(t)
 	for n := 32; n < 33; n++ { // avoid stack allocation of make()