[PATCH, i386]: Fix warning in PR59405

[Uros Bizjak]

Hello!

Currently, gcc emits wrong warning for MMX argument passing on 32 bit
targets, even when MMX is enabled:

pr59405.c: In function ‘foo32x2_be’:
pr59405.c:7:1: warning: SSE vector argument without SSE enabled
changes the ABI [enabled by default]
 foo32x2_be (float32x2_t x)

Attached patch fixes this oversight.

The testcase also tests correct function of necessary _mm_empty intrinsic.

2013-12-06  Uros Bizjak  <ubiz...@gmail.com>

    PR target/59405
    * config/i386/i386.c (type_natural_mode): Properly handle
    size 8 for !TARGET_64BIT.

testsuite/ChangeLog:

2013-12-06  Uros Bizjak  <ubiz...@gmail.com>

    PR target/59405
    * gcc.target/i386/pr59405.c: New test.

Bootstrapped and regression tested on x86_64-pc-linux-gnu {,-m32} and
committed to mainline SVN. The patch will be backported to other
release branches.

Uros.

Index: config/i386/i386.c
===================================================================
--- config/i386/i386.c  (revision 205748)
+++ config/i386/i386.c  (working copy)
@@ -6172,7 +6172,8 @@ type_natural_mode (const_tree type, const CUMULATI
                      }
                    return TYPE_MODE (type);
                  }
-               else if ((size == 8 || size == 16) && !TARGET_SSE)
+               else if (((size == 8 && TARGET_64BIT) || size == 16)
+                        && !TARGET_SSE)
                  {
                    static bool warnedsse;
 
@@ -6184,10 +6185,21 @@ type_natural_mode (const_tree type, const CUMULATI
                        warning (0, "SSE vector argument without SSE "
                                 "enabled changes the ABI");
                      }
-                   return mode;
                  }
-               else
-                 return mode;
+               else if ((size == 8 && !TARGET_64BIT) && !TARGET_MMX)
+                 {
+                   static bool warnedmmx;
+
+                   if (cum
+                       && !warnedmmx
+                       && cum->warn_mmx)
+                     {
+                       warnedmmx = true;
+                       warning (0, "MMX vector argument without MMX "
+                                "enabled changes the ABI");
+                     }
+                 }
+               return mode;
              }
 
          gcc_unreachable ();
Index: testsuite/gcc.target/i386/pr59405.c
===================================================================
--- testsuite/gcc.target/i386/pr59405.c (revision 0)
+++ testsuite/gcc.target/i386/pr59405.c (working copy)
@@ -0,0 +1,24 @@
+/* { dg-do run } */
+/* { dg-options "-mmmx -mfpmath=387" } */
+
+#include "mmx-check.h"
+
+#include <mmintrin.h>
+
+typedef float float32x2_t __attribute__ ((vector_size (8)));
+
+float
+foo32x2_be (float32x2_t x)
+{
+  _mm_empty();
+  return x[1];
+}
+
+static void
+mmx_test (void)
+{
+  float32x2_t b = { 0.0f, 1.0f };
+
+  if (foo32x2_be (b) != 1.0f)
+    abort ();
+}