After emitting probes in a loop last_probe_offset needs to be updated.
Not doing this usually assumes a too low distance to the last access
when emitting the remainder leading to stack probes being omitted.
Bootstrapped and regression tested on s390x
Committed to mainline
gcc/ChangeLog:
2020-05-14 Andreas Krebbel <kreb...@linux.ibm.com>
* config/s390/s390.c (allocate_stack_space): Add missing updates
of last_probe_offset.
gcc/testsuite/ChangeLog:
2020-05-14 Andreas Krebbel <kreb...@linux.ibm.com>
* gcc.target/s390/stack-clash-1.c: New test.
---
gcc/ChangeLog | 5 +++++
gcc/config/s390/s390.c | 3 +++
gcc/testsuite/ChangeLog | 4 ++++
gcc/testsuite/gcc.target/s390/stack-clash-1.c | 17 +++++++++++++++++
4 files changed, 29 insertions(+)
create mode 100644 gcc/testsuite/gcc.target/s390/stack-clash-1.c
diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 0b326ee09e8..51d3e425ad5 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,8 @@
+2020-05-14 Andreas Krebbel <kreb...@linux.ibm.com>
+
+ * config/s390/s390.c (allocate_stack_space): Add missing updates
+ of last_probe_offset.
+
2020-05-14 Andreas Krebbel <kreb...@linux.ibm.com>
* config/s390/s390.md ("allocate_stack"): Call
diff --git a/gcc/config/s390/s390.c b/gcc/config/s390/s390.c
index 18332271ed7..b4897256af5 100644
--- a/gcc/config/s390/s390.c
+++ b/gcc/config/s390/s390.c
@@ -10996,6 +10996,8 @@ allocate_stack_space (rtx size, HOST_WIDE_INT
last_probe_offset,
stack_pointer_rtx,
offset));
}
+ if (num_probes > 0)
+ last_probe_offset = INTVAL (offset);
dump_stack_clash_frame_info (PROBE_INLINE, residual != 0);
}
else
@@ -11029,6 +11031,7 @@ allocate_stack_space (rtx size, HOST_WIDE_INT
last_probe_offset,
s390_prologue_plus_offset (stack_pointer_rtx, temp_reg,
const0_rtx, true);
temp_reg_clobbered_p = true;
+ last_probe_offset = INTVAL (offset);
dump_stack_clash_frame_info (PROBE_LOOP, residual != 0);
}
diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index bb3e4c86adc..8ff0bbcc85b 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,7 @@
+2020-05-14 Andreas Krebbel <kreb...@linux.ibm.com>
+
+ * gcc.target/s390/stack-clash-1.c: New test.
+
2020-05-14 Andreas Krebbel <kreb...@linux.ibm.com>
* gcc.target/s390/stack-clash-3.c: New test.
diff --git a/gcc/testsuite/gcc.target/s390/stack-clash-1.c
b/gcc/testsuite/gcc.target/s390/stack-clash-1.c
new file mode 100644
index 00000000000..3d29cab9446
--- /dev/null
+++ b/gcc/testsuite/gcc.target/s390/stack-clash-1.c
@@ -0,0 +1,17 @@
+/* Make sure a stack probe is emitted also for the remaining bytes
+ after the loop probing the large chunk. */
+
+/* { dg-do compile } */
+/* { dg-options "-O2 -march=z9-ec -fstack-clash-protection" } */
+
+void large_stack() {
+ volatile int stack[8000];
+ int i;
+ for (i = 0; i < sizeof(stack) / sizeof(int); ++i)
+ stack[i] = i;
+}
+
+/* We use a compare for the stack probe. There needs to be one inside
+ a loop and another for the remaining bytes. */
+/* { dg-final { scan-assembler-times "cg\t" 2 { target lp64 } } } */
+/* { dg-final { scan-assembler-times "c\t" 2 { target { ! lp64 } } } } */
--
2.17.1
