Probes emitted by the common code routines still use a store. Define
the "probe_stack" pattern to use a compare instead.
Bootstrapped and regression tested on s390x
Committed to mainline
gcc/ChangeLog:
2020-05-14 Andreas Krebbel <kreb...@linux.ibm.com>
* config/s390/s390.c (s390_emit_stack_probe): Call the probe_stack
expander.
* config/s390/s390.md ("@probe_stack2<mode>", "probe_stack"): New
expanders.
gcc/testsuite/ChangeLog:
2020-05-14 Andreas Krebbel <kreb...@linux.ibm.com>
* gcc.target/s390/stack-clash-2.c: New test.
---
gcc/ChangeLog | 7 +++++++
gcc/config/s390/s390.c | 7 +++----
gcc/config/s390/s390.md | 16 +++++++++++++++-
gcc/testsuite/ChangeLog | 4 ++++
gcc/testsuite/gcc.target/s390/stack-clash-2.c | 17 +++++++++++++++++
5 files changed, 46 insertions(+), 5 deletions(-)
create mode 100644 gcc/testsuite/gcc.target/s390/stack-clash-2.c
diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 51d3e425ad5..5c2366e3671 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,10 @@
+2020-05-14 Andreas Krebbel <kreb...@linux.ibm.com>
+
+ * config/s390/s390.c (s390_emit_stack_probe): Call the probe_stack
+ expander.
+ * config/s390/s390.md ("@probe_stack2<mode>", "probe_stack"): New
+ expanders.
+
2020-05-14 Andreas Krebbel <kreb...@linux.ibm.com>
* config/s390/s390.c (allocate_stack_space): Add missing updates
diff --git a/gcc/config/s390/s390.c b/gcc/config/s390/s390.c
index b4897256af5..4de3129f88e 100644
--- a/gcc/config/s390/s390.c
+++ b/gcc/config/s390/s390.c
@@ -10946,10 +10946,9 @@ s390_prologue_plus_offset (rtx target, rtx reg, rtx
offset, bool frame_related_p
static void
s390_emit_stack_probe (rtx addr)
{
- rtx tmp = gen_rtx_MEM (Pmode, addr);
- MEM_VOLATILE_P (tmp) = 1;
- s390_emit_compare (EQ, gen_rtx_REG (Pmode, 0), tmp);
- emit_insn (gen_blockage ());
+ rtx mem = gen_rtx_MEM (Pmode, addr);
+ MEM_VOLATILE_P (mem) = 1;
+ emit_insn (gen_probe_stack (mem));
}
/* Use a runtime loop if we have to emit more probes than this. */
diff --git a/gcc/config/s390/s390.md b/gcc/config/s390/s390.md
index 908de587e17..cd1c0634b71 100644
--- a/gcc/config/s390/s390.md
+++ b/gcc/config/s390/s390.md
@@ -11017,8 +11017,22 @@
emit_move_insn (operands[0], virtual_stack_dynamic_rtx);
DONE;
-})
+ })
+
+(define_expand "@probe_stack2<mode>"
+ [(set (reg:CCZ CC_REGNUM)
+ (compare:CCZ (reg:P 0)
+ (match_operand 0 "memory_operand")))
+ (unspec_volatile [(const_int 0)] UNSPECV_BLOCKAGE)]
+ "")
+(define_expand "probe_stack"
+ [(match_operand 0 "memory_operand")]
+ ""
+{
+ emit_insn (gen_probe_stack2 (Pmode, operands[0]));
+ DONE;
+})
;
; setjmp instruction pattern.
diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index 8ff0bbcc85b..498ebb7f678 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-2.c: New test.
+
2020-05-14 Andreas Krebbel <kreb...@linux.ibm.com>
* gcc.target/s390/stack-clash-1.c: New test.
diff --git a/gcc/testsuite/gcc.target/s390/stack-clash-2.c
b/gcc/testsuite/gcc.target/s390/stack-clash-2.c
new file mode 100644
index 00000000000..e554ad5ed0d
--- /dev/null
+++ b/gcc/testsuite/gcc.target/s390/stack-clash-2.c
@@ -0,0 +1,17 @@
+/* { dg-do compile } */
+/* { dg-options "-O2 -march=z900 -fstack-clash-protection" } */
+
+extern void bar (char *);
+
+void
+foo ()
+{
+ char * mem = __builtin_alloca (20000);
+ bar (mem);
+}
+
+/* For alloca a common code routine emits the probes. Make sure the
+ "probe_stack" expander is used in that case. We want to use mem
+ compares instead of stores. */
+/* { dg-final { scan-assembler-times "cg\t" 5 { target lp64 } } } */
+/* { dg-final { scan-assembler-times "c\t" 5 { target { ! lp64 } } } } */
--
2.17.1
