[PATCH, i386]: Fix PR 60017 Struct not returned correctly

[Uros Bizjak]

Hello!

There is off-by-one error in classify_argument, when processing
integer atomic types. When bit_offset is 64, two X86_64_INTEGER CLASS
registers should be used.

Attached patch fixes this off-by-one error, so we won't use size = 0
when bit_offset = 64.

2014-02-02  Uros Bizjak  <ubiz...@gmail.com>

    PR target/60017
    * config/i386/i386.c (classify_argument): Fix handling of bit_offset
    when calculating size of integer atomic types.

testsuite/ChangeLog:

2014-02-02  Uros Bizjak  <ubiz...@gmail.com>

    PR target/60017
    * gcc.c-torture/execute/pr60017.c: New test.

Tested on x86_64-linux-gnu, committed to mainline SVN.

Patch will be backported to other release branches in a couple of days.

Uros.

Index: config/i386/i386.c
===================================================================
--- config/i386/i386.c  (revision 207393)
+++ config/i386/i386.c  (working copy)
@@ -6627,25 +6627,28 @@ classify_argument (enum machine_mode mode, const_t
     case CHImode:
     case CQImode:
       {
-       int size = (bit_offset % 64)+ (int) GET_MODE_BITSIZE (mode);
+       int size = bit_offset + (int) GET_MODE_BITSIZE (mode);
 
-       if (size <= 32)
+       /* Analyze last 128 bits only.  */
+       size = (size - 1) & 0x7f;
+
+       if (size < 32)
          {
            classes[0] = X86_64_INTEGERSI_CLASS;
            return 1;
          }
-       else if (size <= 64)
+       else if (size < 64)
          {
            classes[0] = X86_64_INTEGER_CLASS;
            return 1;
          }
-       else if (size <= 64+32)
+       else if (size < 64+32)
          {
            classes[0] = X86_64_INTEGER_CLASS;
            classes[1] = X86_64_INTEGERSI_CLASS;
            return 2;
          }
-       else if (size <= 64+64)
+       else if (size < 64+64)
          {
            classes[0] = classes[1] = X86_64_INTEGER_CLASS;
            return 2;
Index: testsuite/gcc.c-torture/execute/pr60017.c
===================================================================
--- testsuite/gcc.c-torture/execute/pr60017.c   (revision 0)
+++ testsuite/gcc.c-torture/execute/pr60017.c   (working copy)
@@ -0,0 +1,33 @@
+/* PR target/60017 */
+
+extern void abort (void);
+
+struct S0
+{
+  short m0;
+  short m1;
+};
+
+struct S1
+{
+  unsigned m0:1;
+  char m1[2][2];
+  struct S0 m2[2];
+};
+
+struct S1 x = { 1, {{2, 3}, {4, 5}}, {{6, 7}, {8, 9}} };
+
+struct S1 func (void)
+{
+  return x;
+}
+
+int main (void)
+{
+  struct S1 ret = func ();
+
+  if (ret.m2[1].m1 != 9)
+    abort ();
+
+  return 0;
+}