cmd/compile: move stringtoslicebytetmp to the backend

- removes the runtime function stringtoslicebytetmp
- removes the generation of calls to stringtoslicebytetmp from the frontend
- adds handling of OSTRARRAYBYTETMP in the backend

This reduces binary sizes and avoids function call overhead.

Change-Id: Ib9988d48549cee663b685b4897a483f94727b940
Reviewed-on: https://go-review.googlesource.com/32158
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Reviewed-by: Matthew Dempsky <mdempsky@google.com>
Reviewed-by: Josh Bleecher Snyder <josharian@gmail.com>
Run-TryBot: Martin Möhrmann <martisch@uos.de>
TryBot-Result: Gobot Gobot <gobot@golang.org>

1 files changed, 25 insertions, 0 deletions

diff --git a/test/range.go b/test/range.go
index af89edac54..bae7a1c3c9 100644
--- a/test/range.go
+++ b/test/range.go
@@ -110,6 +110,30 @@ func testslice2() {
 	}
 }
 
+// test that range over []byte(string) only evaluates
+// the expression after "range" once.
+
+func makenumstring() string {
+	nmake++
+	return "\x01\x02\x03\x04\x05"
+}
+
+func testslice3() {
+	s := byte(0)
+	nmake = 0
+	for _, v := range []byte(makenumstring()) {
+		s += v
+	}
+	if nmake != 1 {
+		println("range called makenumstring", nmake, "times")
+		panic("fail")
+	}
+	if s != 15 {
+		println("wrong sum ranging over []byte(makenumstring)", s)
+		panic("fail")
+	}
+}
+
 // test that range over array only evaluates
 // the expression after "range" once.
 
@@ -392,6 +416,7 @@ func main() {
 	testslice()
 	testslice1()
 	testslice2()
+	testslice3()
 	teststring()
 	teststring1()
 	teststring2()