[newlib-cygwin] Optimize epilogue sequence for architectures with POP interworking.

[newlib-cygwin] Optimize epilogue sequence for architectures with POP interworking.

[Richard Earnshaw]

https://sourceware.org/git/gitweb.cgi?p=newlib-cygwin.git;h=175b215e054a8cee50d91317f3af22a3b2c3d320

commit 175b215e054a8cee50d91317f3af22a3b2c3d320
Author: Christos Gentsos <christos.gentsos@cern.ch>
Date:   Mon Oct 7 14:38:14 2019 +0100

    Optimize epilogue sequence for architectures with POP interworking.
    
    ARMv5 and above supports arm/thumb interworking using POP, so we can
    improve the exit sequence in this case.

Diff:
---
 newlib/libc/machine/arm/aeabi_memmove-thumb.S | 6 ++++++
 newlib/libc/machine/arm/aeabi_memset-thumb.S  | 6 ++++++
 2 files changed, 12 insertions(+)

diff --git a/newlib/libc/machine/arm/aeabi_memmove-thumb.S b/newlib/libc/machine/arm/aeabi_memmove-thumb.S
index 61a7258..fadeb9a 100644
--- a/newlib/libc/machine/arm/aeabi_memmove-thumb.S
+++ b/newlib/libc/machine/arm/aeabi_memmove-thumb.S
@@ -26,6 +26,8 @@
  * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 
+#include "acle-compat.h"
+
 	.thumb
 	.syntax unified
 	.global __aeabi_memmove
@@ -49,9 +51,13 @@ __aeabi_memmove:
 	subs	r3, r3, #1
 	bcs	1b
 2:
+#if __ARM_ARCH >= 5
+	pop	{r4, pc}
+#else
 	pop	{r4}
 	pop	{r1}
 	bx	r1
+#endif
 3:
 	movs	r3, #0
 	cmp	r2, #0
diff --git a/newlib/libc/machine/arm/aeabi_memset-thumb.S b/newlib/libc/machine/arm/aeabi_memset-thumb.S
index aa8f271..ed6ce88 100644
--- a/newlib/libc/machine/arm/aeabi_memset-thumb.S
+++ b/newlib/libc/machine/arm/aeabi_memset-thumb.S
@@ -26,6 +26,8 @@
  * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 
+#include "acle-compat.h"
+
 	.thumb
 	.syntax unified
 	.global __aeabi_memset
@@ -110,9 +112,13 @@ __aeabi_memset:
 	cmp	r4, r3
 	bne	8b
 9:
+#if __ARM_ARCH >= 5
+	pop	{r4, r5, r6, pc}
+#else
 	pop	{r4, r5, r6}
 	pop	{r1}
 	bx	r1
+#endif
 10:
 	movs	r3, r0
 	movs	r4, r1