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From: "foom at fuhm dot net" <gcc-bugzilla@gcc.gnu.org> To: gcc-bugs@gcc.gnu.org Subject: [Bug target/98522] New: _mm_cvttps_pi32 and _mm_cvtps_pi32 raise spurious FP exceptions Date: Tue, 05 Jan 2021 02:54:42 +0000 [thread overview] Message-ID: <bug-98522-4@http.gcc.gnu.org/bugzilla/> (raw) https://gcc.gnu.org/bugzilla/show_bug.cgi?id=98522 Bug ID: 98522 Summary: _mm_cvttps_pi32 and _mm_cvtps_pi32 raise spurious FP exceptions Product: gcc Version: 11.0 Status: UNCONFIRMED Severity: normal Priority: P3 Component: target Assignee: unassigned at gcc dot gnu.org Reporter: foom at fuhm dot net Target Milestone: --- This is a regression due to the MMX in SSE work in GCC10. As far as I can tell, it affects only these two functions. Example test, which should return 0, but instead throws SIGFPE: #pragma stdc fenv_access #define _GNU_SOURCE #include <emmintrin.h> #include <fenv.h> __attribute__((noinline)) __m64 test(__m128 a) { return _mm_cvtt_ps2pi(a); } int main() { feenableexcept(FE_INVALID); __m128 x = (__m128)(__m128i){0x0000000000000000LL, 0x7fffffffffffffffLL}; volatile __m64 y = test(x); } In GCC 10 and trunk, the function test is compiled to: cvttps2dq xmm0, xmm0 ret which will convert the upper 64 bits as well as the lower 64 bits -- and therefore raises FP exceptions accordingly. But, it ought to be ignoring the upper 64bits.
next reply other threads:[~2021-01-05 2:54 UTC|newest] Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top 2021-01-05 2:54 foom at fuhm dot net [this message] 2021-01-05 10:07 ` [Bug target/98522] " ubizjak at gmail dot com 2021-01-06 9:47 ` ubizjak at gmail dot com
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