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SPU/PPU LLVM: Fix FMA signed zeroes handling

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This commit is contained in:
Eladash 2020-08-05 18:03:21 +03:00 • committed by Ani
parent f188589685
commit 7e11855330
2 changed files with 40 additions and 15 deletions
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2
rpcs3/Emu/Cell/PPUTranslator.cpp
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@ -948,7 +948,7 @@ void PPUTranslator::VMADDFP(ppu_opcode_t op)
// Optimization: Emit only a floating multiply if the addend is zero
if (auto [ok, data] = get_const_vector(b.value, m_addr, 2000); ok)
{
if (data == v128{})
if (data == v128::from32p(1u << 31))
{
set_vr(op.vd, vec_handle_result(a * c));
ppu_log.notice("LLVM: VMADDFP with 0 addend at [0x%08x]", m_addr + (m_reloc ? m_reloc->addr : 0));

53
rpcs3/Emu/Cell/SPURecompiler.cpp
View file

@ -7483,13 +7483,14 @@ public:
}
// Checks for postive and negative zero, or Denormal (treated as zero)
bool is_spu_float_zero(v128 a)
// If sign is +-1 check equality againts all sign bits
bool is_spu_float_zero(v128 a, int sign = 0)
{
for (u32 i = 0; i < 4; i++)
{
const u32 exponent = a._u32[i] & 0x7f800000u;
if (exponent)
if (exponent || (sign && (sign >= 0) != (a._s32[i] >= 0)))
{
// Normalized number
return false;
@ -7727,28 +7728,52 @@ public:
// This is odd since SPU code could just use the FM instruction, but it seems common enough
if (auto [ok, data] = get_const_vector(c.value, m_pos, 4000); ok)
{
if (is_spu_float_zero(data))
if (is_spu_float_zero(data, -1))
{
r = eval(a * b);
return r;
}
}
if (auto [ok, data] = get_const_vector(b.value, m_pos, 4000); ok)
if ([&]()
{
if (is_spu_float_zero(data))
if (auto [ok, data] = get_const_vector(a.value, m_pos, 4000); ok)
{
// Just return the added value if either a or b is 0
return c;
}
}
if (!is_spu_float_zero(data, +1))
{
return false;
}
if (auto [ok, data] = get_const_vector(a.value, m_pos, 4000); ok)
{
if (is_spu_float_zero(data))
{
return c;
if (auto [ok0, data0] = get_const_vector(b.value, m_pos, 4000); ok0)
{
if (is_spu_float_zero(data0, +1))
{
return true;
}
}
}
if (auto [ok, data] = get_const_vector(a.value, m_pos, 4000); ok)
{
if (!is_spu_float_zero(data, -1))
{
return false;
}
if (auto [ok0, data0] = get_const_vector(b.value, m_pos, 4000); ok0)
{
if (is_spu_float_zero(data0, -1))
{
return true;
}
}
}
return false;
}())
{
// Just return the added value if both a and b is +0 or -0 (+0 and -0 arent't allowed alone)
return c;
}
if (m_use_fma)