cmd/compile: schedule induction variable increments late

for ..; ..; i++ {
 ...
}

We want to schedule the i++ late in the block, so that all other
uses of i in the block are scheduled first. That way, i++ can
happen in place in a register instead of requiring a temporary register.

Change-Id: Id777407c7e67a5ddbd8e58251099b0488138c0df
Reviewed-on: https://go-review.googlesource.com/c/go/+/672998
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Reviewed-by: David Chase <drchase@google.com>
Reviewed-by: Keith Randall <khr@google.com>

1 files changed, 17 insertions, 0 deletions

diff --git a/test/codegen/schedule.go b/test/codegen/schedule.go
new file mode 100644
index 0000000000..aafffd817b
--- /dev/null
+++ b/test/codegen/schedule.go
@@ -0,0 +1,17 @@
+// asmcheck
+
+// Copyright 2025 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 codegen
+
+func f(n int) int {
+	r := 0
+	// arm64:-"MOVD\t R"
+	// amd64:-"LEAQ","INCQ"
+	for i := range n {
+		r += i
+	}
+	return r
+}