* config/i386/cygming.h (STACK_REALIGN_DEFAULT): Define.

From-SVN: r233791

gcc/ChangeLog

+2016-02-28  Eric Botcazou  <ebotcazou@adacore.com>
+
+	* config/i386/cygming.h (STACK_REALIGN_DEFAULT): Define.
+
 2016-02-27  Jeff Law  <law@redhat.com>
 
 	Revert

gcc/config/i386/cygming.h

@@ -39,6 +39,11 @@ along with GCC; see the file COPYING3.  If not see
 #undef MAX_STACK_ALIGNMENT
 #define MAX_STACK_ALIGNMENT  (TARGET_SEH ? 128 : MAX_OFILE_ALIGNMENT)
 
+/* 32-bit Windows aligns the stack on a 4-byte boundary but SSE instructions
+   may require 16-byte alignment.  */
+#undef STACK_REALIGN_DEFAULT
+#define STACK_REALIGN_DEFAULT TARGET_SSE
+
 /* Support hooks for SEH.  */
 #undef  TARGET_ASM_UNWIND_EMIT
 #define TARGET_ASM_UNWIND_EMIT  i386_pe_seh_unwind_emit

gcc/testsuite/ChangeLog

+2016-02-28  Eric Botcazou  <ebotcazou@adacore.com>
+
+	* gcc.target/i386/stack-realign-win.c: New test.
+
 2016-02-28  Harald Anlauf  <anlauf@gmx.de>
 
 	PR fortran/60126

gcc/testsuite/gcc.target/i386/stack-realign-win.c

+/* { dg-do compile { target *-*-mingw* *-*-cygwin* } } */
+/* { dg-require-effective-target ia32 } */
+/* { dg-options "-msse -O" } */
+
+extern void abort (void);
+
+typedef float __m128 __attribute__ ((__vector_size__ (16), __may_alias__));
+
+static __m128
+load_m128 (float *e)
+{
+  return * (__m128 *) e;
+}
+
+typedef union
+{
+  __m128  x;
+  float a[4];
+} union128;
+
+void test (void)
+{
+  union128 u;
+  float e[4] __attribute__ ((aligned (16)))
+    = {2134.3343, 1234.635654, 1.2234, 876.8976};
+  int i;
+
+  u.x = load_m128 (e);
+
+  for (i = 0; i < 4; i++)
+    if (u.a[i] != e[i])
+      abort ();
+}
+
+/* { dg-final { scan-assembler "andl\\t\\$-16, %esp" } } */