AVR: target/119989 - Add missing clobbers to xload_<mode>_libgcc.

libgcc's __xload_1...4 is clobbering Z (and also R21 is some cases),
but avr.md had clobbers of respective GPRs only up to reload.
Outcome was that code reading from the same __memx address twice
could be wrong.  This patch adds respective clobbers.

gcc/
	* config/avr/avr.md (xload_<mode>_libgcc): Clobber R21, Z.

gcc/testsuite/
	* gcc.target/avr/torture/pr119989.h: New file.
	* gcc.target/avr/torture/pr119989-memx-1.c: New test.
	* gcc.target/avr/torture/pr119989-memx-2.c: New test.
	* gcc.target/avr/torture/pr119989-memx-3.c: New test.
	* gcc.target/avr/torture/pr119989-memx-4.c: New test.

diff --git a/gcc/config/avr/avr.md b/gcc/config/avr/avr.md
index 823fc716f2c7757e9f3f0809138f3ec7d0c732fd..e07626dc1096819c2666caa5827fbbb96acbfba8 100644 (file)
--- a/gcc/config/avr/avr.md
+++ b/gcc/config/avr/avr.md
@@ -674,12 +674,16 @@
   [(parallel [(set (reg:MOVMODE 22)
               (mem:MOVMODE (lo_sum:PSI (reg:QI 21)
                                        (reg:HI REG_Z))))
+              (clobber (reg:QI 21))
+              (clobber (reg:HI REG_Z))
               (clobber (reg:CC REG_CC))])])
 
 (define_insn "*xload_<mode>_libgcc"
   [(set (reg:MOVMODE 22)
         (mem:MOVMODE (lo_sum:PSI (reg:QI 21)
                                  (reg:HI REG_Z))))
+   (clobber (reg:QI 21))
+   (clobber (reg:HI REG_Z))
    (clobber (reg:CC REG_CC))]
   "avr_xload_libgcc_p (<MODE>mode)
    && reload_completed"

diff --git a/gcc/testsuite/gcc.target/avr/torture/pr119989-memx-1.c b/gcc/testsuite/gcc.target/avr/torture/pr119989-memx-1.c
new file mode 100644 (file)
index 0000000..27b89e4
--- /dev/null
+++ b/gcc/testsuite/gcc.target/avr/torture/pr119989-memx-1.c
@@ -0,0 +1,6 @@
+/* { dg-do run { target { ! avr_tiny } } } */
+/* { dg-additional-options "-std=gnu99" } */
+
+typedef __UINT8_TYPE__ TYP;
+
+#include "pr119989.h"

diff --git a/gcc/testsuite/gcc.target/avr/torture/pr119989-memx-2.c b/gcc/testsuite/gcc.target/avr/torture/pr119989-memx-2.c
new file mode 100644 (file)
index 0000000..a8011a2
--- /dev/null
+++ b/gcc/testsuite/gcc.target/avr/torture/pr119989-memx-2.c
@@ -0,0 +1,6 @@
+/* { dg-do run { target { ! avr_tiny } } } */
+/* { dg-additional-options "-std=gnu99" } */
+
+typedef __UINT16_TYPE__ TYP;
+
+#include "pr119989.h"

diff --git a/gcc/testsuite/gcc.target/avr/torture/pr119989-memx-3.c b/gcc/testsuite/gcc.target/avr/torture/pr119989-memx-3.c
new file mode 100644 (file)
index 0000000..ea1c4b6
--- /dev/null
+++ b/gcc/testsuite/gcc.target/avr/torture/pr119989-memx-3.c
@@ -0,0 +1,6 @@
+/* { dg-do run { target { ! avr_tiny } } } */
+/* { dg-additional-options "-std=gnu99" } */
+
+__extension__ typedef __uint24 TYP;
+
+#include "pr119989.h"

diff --git a/gcc/testsuite/gcc.target/avr/torture/pr119989-memx-4.c b/gcc/testsuite/gcc.target/avr/torture/pr119989-memx-4.c
new file mode 100644 (file)
index 0000000..32b5cd3
--- /dev/null
+++ b/gcc/testsuite/gcc.target/avr/torture/pr119989-memx-4.c
@@ -0,0 +1,6 @@
+/* { dg-do run { target { ! avr_tiny } } } */
+/* { dg-additional-options "-std=gnu99" } */
+
+typedef __UINT32_TYPE__ TYP;
+
+#include "pr119989.h"

diff --git a/gcc/testsuite/gcc.target/avr/torture/pr119989.h b/gcc/testsuite/gcc.target/avr/torture/pr119989.h
new file mode 100644 (file)
index 0000000..ab9d14a
--- /dev/null
+++ b/gcc/testsuite/gcc.target/avr/torture/pr119989.h
@@ -0,0 +1,37 @@
+const __memx TYP some_data[] = { 1, 2, 3, 4, 5 };
+const __memx TYP *IP;
+
+TYP DT, a, b;
+
+__attribute__((noipa))
+void do_test1 (void)
+{
+    DT = *IP;
+    DT = *IP--;
+}
+
+__attribute__((noipa))
+void do_test2 (void)
+{
+    DT = *IP;
+    __asm volatile ("" ::: "memory"); // Prevents unwanted optimization
+    DT = *IP--;
+}
+
+TYP difference(void)
+{
+    IP = &some_data[3];
+    do_test1();
+    a = DT;
+    IP = &some_data[3];
+    do_test2();
+    b = DT;
+    return a - b; // Expected: 0
+}
+
+int main (void)
+{
+    if (difference () != 0)
+        __builtin_exit (__LINE__);
+    return 0;
+}