This tests are intended to reveal the respective PRs because the test
case is more stable under slight variations in code (both of
application or compiler).
This test case migh also be helpful for older versions of avr-gcc, in
particular if PR41894 is actually fixed.
2011-04-14 Georg-Johann Lay <a...@gjlay.de>
PR target/46779
PR target/45291
PR target/41894
* gcc.target/avr/pr46779-1.c: New test case
* gcc.target/avr/pr46779-2.c: New test case
Index: gcc.target/avr/pr46779-1.c
===================================================================
--- gcc.target/avr/pr46779-1.c (Revision 0)
+++ gcc.target/avr/pr46779-1.c (Revision 0)
@@ -0,0 +1,51 @@
+/* { dg-do run } */
+/* { dg-options "-Os -fsplit-wide-types" } */
+
+/* This testcase should uncover bugl like
+ PR46779
+ PR45291
+ PR41894
+
+ The inline asm just serves to direct y into the Y register.
+ Otherwise, it is hard to write a "stable" test case that
+ also fails with sligh variations in source code, middle- resp.
+ backend.
+
+ The problem is that Y is also the frame-pointer, and
+ avr.c:avr_hard_regno_mode_ok disallows QI to get in Y-reg.
+ However, the y.a = 0 generates a
+ (set (subreg:QI (reg:HI pseudo)) ...)
+ where pseudo gets allocated to Y.
+
+ Reload fails to generate the right spill.
+*/
+
+#include <stdlib.h>
+
+struct S
+{
+ unsigned char a, b;
+} ab = {12, 34};
+
+void yoo (struct S y)
+{
+ __asm volatile ("ldi %B0, 56" : "+y" (y));
+ y.a = 0;
+ __asm volatile ("; y = %0" : "+y" (y));
+ ab = y;
+}
+
+int main ()
+{
+ yoo (ab);
+
+ if (ab.a != 0)
+ abort();
+
+ if (ab.b != 56)
+ abort();
+
+ exit (0);
+
+ return 0;
+}
Index: gcc.target/avr/pr46779-2.c
===================================================================
--- gcc.target/avr/pr46779-2.c (Revision 0)
+++ gcc.target/avr/pr46779-2.c (Revision 0)
@@ -0,0 +1,51 @@
+/* { dg-do run } */
+/* { dg-options "-Os -fno-split-wide-types" } */
+
+/* This testcase should uncover bugl like
+ PR46779
+ PR45291
+ PR41894
+
+ The inline asm just serves to direct y into the Y register.
+ Otherwise, it is hard to write a "stable" test case that
+ also fails with sligh variations in source code, middle- resp.
+ backend.
+
+ The problem is that Y is also the frame-pointer, and
+ avr.c:avr_hard_regno_mode_ok disallows QI to get in Y-reg.
+ However, the y.a = 0 generates a
+ (set (subreg:QI (reg:HI pseudo)) ...)
+ where pseudo gets allocated to Y.
+
+ Reload fails to generate the right spill.
+*/
+
+#include <stdlib.h>
+
+struct S
+{
+ unsigned char a, b;
+} ab = {12, 34};
+
+void yoo (struct S y)
+{
+ __asm volatile ("ldi %B0, 56" : "+y" (y));
+ y.a = 0;
+ __asm volatile ("; y = %0" : "+y" (y));
+ ab = y;
+}
+
+int main ()
+{
+ yoo (ab);
+
+ if (ab.a != 0)
+ abort();
+
+ if (ab.b != 56)
+ abort();
+
+ exit (0);
+
+ return 0;
+}
