[Bug target/89993] Inconsistent incoming stack boundary

[hjl.tools at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=89993

--- Comment #2 from H.J. Lu <hjl.tools at gmail dot com> ---
(In reply to Uroš Bizjak from comment #1)
> (In reply to H.J. Lu from comment #0)
> > It looks like the default incoming stack isn't a constant:
> And where is the bug?

The bug is that -mstackrealign has different behaviors on tail call,
depending on if -mincoming-stack-boundary=4 or

__m128 x;

is used.  I am expecting the same tail call optimization with

-mstackrealign -S -O2

for

int tst2Foo(int*, int*, int);

int tst1Foo(int* pSrc, int* pDst, int len)
{
  return tst2Foo(pSrc, pDst, len);
}

and

#include <xmmintrin.h>

int tst2Foo(int*, int*, int, __m128*);

int tst1Foo(int* pSrc, int* pDst, int len)
{
  __m128 x;
  return tst2Foo(pSrc, pDst, len, &x);
}

with and without -mincoming-stack-boundary=4.