https://gcc.gnu.org/bugzilla/show_bug.cgi?id=114487
--- Comment #2 from Uroš Bizjak <ubizjak at gmail dot com> ---
(In reply to Richard Biener from comment #1)
> (insn 6 5 0 (set (reg/v:SF 99 [ gamma ])
> (reg:SF 20 xmm0)) "testautomation-testautomation_pixels.i":15:17 -1
> (nil))
>
> I'm not sure what's wrong - looks like a target issue to me.
We are working with SFmode, so -msse is enough to trigger the bug.
This is known issue. GCC assumes that at least moves of all hard registers are
working, which is not the case when LTO-compiling
testautomation-testautomation_pixels.i with SDL_test_fuzzer.o (that enables and
uses XMM registers via -msse -mfpmath=sse).
It looks to me that the compiler hits this part in function_value_32 when
LTO-compiling:
--cut here--
/* Override FP return register with %xmm0 for local functions when
SSE math is enabled or for functions with sseregparm attribute. */
if ((fn || fntype) && (mode == SFmode || mode == DFmode))
{
int sse_level = ix86_function_sseregparm (fntype, fn, false);
if (sse_level == -1)
{
error ("calling %qD with SSE calling convention without "
"SSE/SSE2 enabled", fn);
sorry ("this is a GCC bug that can be worked around by adding "
"attribute used to function called");
}
else if ((sse_level >= 1 && mode == SFmode)
|| (sse_level == 2 && mode == DFmode))
regno = FIRST_SSE_REG;
}
--cut here--
Adding -msse to the second compilation works OK, removing -mfpmath=sse from the
first compilation also works OK.
