[PATCH] s390: Add emit_barrier() after trap.

[Dominik Vogt]

This patch fixes an ICE on S390 when a trap is generated because
the given -mstack-size is to small.  A barrier was missing after
the trap, so on higher optimization levels a NULL pointer fron an
uninitialized basic block was used.  The patch also contains a
test case.

Ciao

Dominik ^_^  ^_^

-- 

Dominik Vogt
IBM Germany

gcc/ChangeLog
 
        * config/s390/s390.c (s390_emit_prologue): Add emit_barrier() after
        trap to fix ICE.

gcc/testsuite/ChangeLog
 
        * gcc.target/s390/20150826-1.c: New test.

>From ec6b88cd51234d138bd559271def086156fcae07 Mon Sep 17 00:00:00 2001
From: Dominik Vogt <v...@linux.vnet.ibm.com>
Date: Wed, 26 Aug 2015 14:37:00 +0100
Subject: [PATCH] s390: Add emit_barrier() after trap.

---
 gcc/config/s390/s390.c                     |  1 +
 gcc/testsuite/gcc.target/s390/20150826-1.c | 11 +++++++++++
 2 files changed, 12 insertions(+)
 create mode 100644 gcc/testsuite/gcc.target/s390/20150826-1.c

diff --git a/gcc/config/s390/s390.c b/gcc/config/s390/s390.c
index 6366691..5951598 100644
--- a/gcc/config/s390/s390.c
+++ b/gcc/config/s390/s390.c
@@ -10491,6 +10491,7 @@ s390_emit_prologue (void)
 		       current_function_name(), cfun_frame_layout.frame_size,
 		       s390_stack_size);
 	      emit_insn (gen_trap ());
+	      emit_barrier ();
 	    }
 	  else
 	    {
diff --git a/gcc/testsuite/gcc.target/s390/20150826-1.c b/gcc/testsuite/gcc.target/s390/20150826-1.c
new file mode 100644
index 0000000..830772f
--- /dev/null
+++ b/gcc/testsuite/gcc.target/s390/20150826-1.c
@@ -0,0 +1,11 @@
+/* Check that -mstack-size=32 does not cause an ICE.  */
+
+/* { dg-do compile } */
+/* { dg-options "-O3 -mstack-size=32 -Wno-pointer-to-int-cast" } */
+
+extern char* bar(char *);
+int foo(void)
+{
+  char b[100];
+  return (int)bar(b);
+} /* { dg-warning "An unconditional trap is added" } */
-- 
2.3.0