[Bug target/88671] New: generic vector passed in MMX regs

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=88671

            Bug ID: 88671
           Summary: generic vector passed in MMX regs
           Product: gcc
           Version: 9.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: target
          Assignee: unassigned at gcc dot gnu.org
          Reporter: rguenth at gcc dot gnu.org
  Target Milestone: ---

typedef unsigned int U32;
typedef U32 U32x2 __attribute__((vector_size(8)));
typedef U32 U32x4 __attribute__((vector_size(16)));

void bar2(U32x2);
void foo2(U32x2 *p)
{
  bar2(*p);
}

void bar4(U32x4);
void foo4(U32x4 *p)
{
  bar4(*p);
}

shows bar2/foo2 passing U32x2 in MMX regs on i?86-linux with -msse2
(on the stack when using -mno-mmx).  On x86_64-linux args are passed in
SSE regs.

clang passes U32x2 values on the stack on i?86-linux independent of
-m[no-]mmx.