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avutil/cpu: move slow gather checks below in the function
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Put them together with other similar slow flag checks.

Signed-off-by: James Almer <[email protected]>
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jamrial committed Dec 21, 2021
1 parent eebe406 commit 8c2d2fd
Showing 1 changed file with 9 additions and 14 deletions.
23 changes: 9 additions & 14 deletions libavutil/x86/cpu.c
Original file line number Diff line number Diff line change
Expand Up @@ -146,21 +146,8 @@ int ff_get_cpu_flags_x86(void)
if (max_std_level >= 7) {
cpuid(7, eax, ebx, ecx, edx);
#if HAVE_AVX2
if ((rval & AV_CPU_FLAG_AVX) && (ebx & 0x00000020)) {
if ((rval & AV_CPU_FLAG_AVX) && (ebx & 0x00000020))
rval |= AV_CPU_FLAG_AVX2;
cpuid(1, eax, ebx, ecx, std_caps);
family = ((eax >> 8) & 0xf) + ((eax >> 20) & 0xff);
model = ((eax >> 4) & 0xf) + ((eax >> 12) & 0xf0);
/* Haswell has slow gather */
if (!strncmp(vendor.c, "GenuineIntel", 12))
if (family == 6 && model < 70)
rval |= AV_CPU_FLAG_SLOW_GATHER;
/* Zen 3 and earlier have slow gather */
if (!strncmp(vendor.c, "AuthenticAMD", 12))
if (family <= 0x19)
rval |= AV_CPU_FLAG_SLOW_GATHER;
}

#if HAVE_AVX512 /* F, CD, BW, DQ, VL */
if ((xcr0_lo & 0xe0) == 0xe0) { /* OPMASK/ZMM state */
if ((rval & AV_CPU_FLAG_AVX2) && (ebx & 0xd0030000) == 0xd0030000)
Expand Down Expand Up @@ -209,6 +196,10 @@ int ff_get_cpu_flags_x86(void)
used unless explicitly disabled by checking AV_CPU_FLAG_AVXSLOW. */
if ((family == 0x15 || family == 0x16) && (rval & AV_CPU_FLAG_AVX))
rval |= AV_CPU_FLAG_AVXSLOW;

/* Zen 3 and earlier have slow gather */
if ((family <= 0x19) && (rval & AV_CPU_FLAG_AVX2))
rval |= AV_CPU_FLAG_SLOW_GATHER;
}

/* XOP and FMA4 use the AVX instruction coding scheme, so they can't be
Expand Down Expand Up @@ -248,6 +239,10 @@ int ff_get_cpu_flags_x86(void)
if ((rval & AV_CPU_FLAG_SSSE3) && !(rval & AV_CPU_FLAG_SSE4) &&
family == 6 && model < 23)
rval |= AV_CPU_FLAG_SSSE3SLOW;

/* Haswell has slow gather */
if ((rval & AV_CPU_FLAG_AVX2) && family == 6 && model < 70)
rval |= AV_CPU_FLAG_SLOW_GATHER;
}

#endif /* cpuid */
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