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emit_x64_vector: Bugfix for EmitVectorLogicalShiftRight8: shift_amount can be >= 8

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This commit is contained in:
Merry 2021-03-27 21:32:07 +00:00
parent 91337788ee
commit 4d33feb1fa
1 changed files with 12 additions and 11 deletions
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23
src/backend/x64/emit_x64_vector.cpp
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@ -1524,18 +1524,19 @@ void EmitX64::EmitVectorLogicalShiftRight8(EmitContext& ctx, IR::Inst* inst) {
const Xbyak::Xmm result = ctx.reg_alloc.UseScratchXmm(args[0]);
const u8 shift_amount = args[1].GetImmediateU8();
if (shift_amount > 0) {
if (code.HasAVX512_Icelake()) {
// Galois 8x8 identity matrix, bit-shifted by the shift-amount
const u64 shift_matrix = 0x0102040810204080 << (shift_amount * 8);
code.vgf2p8affineqb(result, result, code.MConst(xword_b, shift_matrix), 0);
} else {
const u64 replicand = 0xFEULL >> shift_amount;
const u64 mask = Common::Replicate(replicand, Common::BitSize<u8>());
if (shift_amount == 0) {
// Do nothing
} else if (shift_amount >= 8) {
code.pxor(result, result);
} else if (code.HasAVX512_Icelake()) {
const u64 shift_matrix = 0x0102040810204080 << (shift_amount * 8);
code.vgf2p8affineqb(result, result, code.MConst(xword_b, shift_matrix), 0);
} else {
const u64 replicand = 0xFEULL >> shift_amount;
const u64 mask = Common::Replicate(replicand, Common::BitSize<u8>());
code.psrlw(result, shift_amount);
code.pand(result, code.MConst(xword, mask, mask));
}
code.psrlw(result, shift_amount);
code.pand(result, code.MConst(xword, mask, mask));
}
ctx.reg_alloc.DefineValue(inst, result);