re PR libgcc/86213 (-fsplit-stack runtime may clobber SSE input param reg)

libgcc/:
	PR libgcc/86213
	* generic-morestack.c (allocate_segment): Move calls to getenv and
	getpagesize to __morestack_load_mmap.
	(__morestack_load_mmap) Initialize static_pagesize and
	use_guard_page here so as to avoid clobbering SSE regs during a
	__morestack call.
gcc/testsuite/:
	* gcc.dg/split-8.c: New.

From-SVN: r261823

2 files changed, 48 insertions, 0 deletions

diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index 0343e8e..2e333b4 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,8 @@
+2018-06-20  Than McIntosh  <thanm@google.com>
+
+	PR libgcc/86213
+	* gcc.dg/split-8.c: New.
+
 2018-06-20  Kelvin Nilsen  <kelvin@gcc.gnu.org>
 
 	* gcc.target/powerpc/builtins-1.c: Adjust dg directives to scan
diff --git a/gcc/testsuite/gcc.dg/split-8.c b/gcc/testsuite/gcc.dg/split-8.c
new file mode 100644
index 0000000..33662e2
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/split-8.c
@@ -0,0 +1,43 @@
+/* { dg-do run } */
+/* { dg-require-effective-target split_stack } */
+/* { dg-options "-fsplit-stack" } */
+
+/* Testcase for PR86213. On the first call to __morestack there is a live
+   value in xmm0, which was being clobbered by a call to getenv().  */
+
+#include <stdlib.h>
+
+double gd[8];
+int z;
+
+double bar(double q)  __attribute__ ((noinline));
+double foo(double q)  __attribute__ ((noinline));
+int ck(double q)  __attribute__ ((noinline));
+int main(int argc, char **argv) __attribute__ ((no_split_stack));
+
+double bar(double q)
+{
+  double d[8];
+  for (unsigned i = 0; i < 8; ++i)
+    d[i] = gd[8-i-1];
+  return q + d[z&3];
+}
+
+double foo(double d)
+{
+  return bar(d);
+}
+
+int ck(double d)
+{
+  if (d != 64.0)
+    abort();
+  return 0;
+}
+
+typedef double (*fp)(double);
+fp g = foo;
+
+int main(int argc, char **argv) {
+  return ck(g(64.0));
+}