PR target/39137

[pf3gnuchains/gcc-fork.git] / gcc / config / i386 / i386.c

diff --git a/gcc/config/i386/i386.c b/gcc/config/i386/i386.c
index e7dd5be..9a34912 100644 (file)
--- a/gcc/config/i386/i386.c
+++ b/gcc/config/i386/i386.c
@@ -19347,15 +19347,39 @@ ix86_data_alignment (tree type, int align)
   return align;
 }
 
-/* Compute the alignment for a local variable or a stack slot.  TYPE is
-   the data type, MODE is the widest mode available and ALIGN is the
-   alignment that the object would ordinarily have.  The value of this
-   macro is used instead of that alignment to align the object.  */
+/* Compute the alignment for a local variable or a stack slot.  EXP is
+   the data type or decl itself, MODE is the widest mode available and
+   ALIGN is the alignment that the object would ordinarily have.  The
+   value of this macro is used instead of that alignment to align the
+   object.  */
 
 unsigned int
-ix86_local_alignment (tree type, enum machine_mode mode,
+ix86_local_alignment (tree exp, enum machine_mode mode,
                      unsigned int align)
 {
+  tree type, decl;
+
+  if (exp && DECL_P (exp))
+    {
+      type = TREE_TYPE (exp);
+      decl = exp;
+    }
+  else
+    {
+      type = exp;
+      decl = NULL;
+    }
+
+  /* Don't do dynamic stack realignment for long long objects with
+     -mpreferred-stack-boundary=2.  */
+  if (!TARGET_64BIT
+      && align == 64
+      && ix86_preferred_stack_boundary < 64
+      && (mode == DImode || (type && TYPE_MODE (type) == DImode))
+      && (!type || !TYPE_USER_ALIGN (type))
+      && (!decl || !DECL_USER_ALIGN (decl)))
+    align = 32;
+
   /* If TYPE is NULL, we are allocating a stack slot for caller-save
      register in MODE.  We will return the largest alignment of XF
      and DF.  */