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riscv: Reduce norms in Slt/Sltu overlap cases.

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We can skip an SEXT.W in common cases where the dest and src overlap.
This commit is contained in:
Unknown W. Brackets committed 2023-07-30 14:19:28 -07:00
1 parent d1dc346899
commit e34736fbb2
1 file changed
+22 -13
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Core/MIPS/RiscV/RiscVCompALU.cpp
+22 -13
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@@ -374,21 +374,27 @@ void RiscVJit::CompIR_Compare(IRInst inst) {
RiscVReg rhs = INVALID_REG;
switch (inst.op) {
case IROp::Slt:
// Not using the NORM32 flag so we don't confuse ourselves on overlap.
gpr.MapDirtyInIn(inst.dest, inst.src1, inst.src2);
gpr.SpillLock(inst.dest, inst.src1, inst.src2);
gpr.MapReg(inst.src1);
gpr.MapReg(inst.src2);
NormalizeSrc12(inst, &lhs, &rhs, SCRATCH1, SCRATCH2, true);
gpr.MapReg(inst.dest, MIPSMap::NOINIT | MIPSMap::MARK_NORM32);
gpr.ReleaseSpillLock(inst.dest, inst.src1, inst.src2);
SLT(gpr.R(inst.dest), lhs, rhs);
gpr.MarkDirty(gpr.R(inst.dest), true);
break;
case IROp::SltConst:
// Not using the NORM32 flag so we don't confuse ourselves on overlap.
gpr.MapDirtyIn(inst.dest, inst.src1);
if (inst.constant == 0) {
// Basically, getting the sign bit. Let's shift instead.
gpr.MapDirtyIn(inst.dest, inst.src1, MapType::AVOID_LOAD_MARK_NORM32);
SRLIW(gpr.R(inst.dest), gpr.R(inst.src1), 31);
} else {
gpr.SpillLock(inst.dest, inst.src1);
gpr.MapReg(inst.src1);
NormalizeSrc1(inst, &lhs, SCRATCH1, false);
gpr.MapReg(inst.dest, MIPSMap::NOINIT | MIPSMap::MARK_NORM32);
gpr.ReleaseSpillLock(inst.dest, inst.src1);
if ((int32_t)inst.constant >= -2048 && (int32_t)inst.constant <= 2047) {
SLTI(gpr.R(inst.dest), lhs, (int32_t)inst.constant);
@@ -396,26 +402,31 @@ void RiscVJit::CompIR_Compare(IRInst inst) {
LI(SCRATCH2, (int32_t)inst.constant);
SLT(gpr.R(inst.dest), lhs, SCRATCH2);
}
gpr.MarkDirty(gpr.R(inst.dest), true);
}
gpr.MarkDirty(gpr.R(inst.dest), true);
break;
case IROp::SltU:
// Not using the NORM32 flag so we don't confuse ourselves on overlap.
gpr.MapDirtyInIn(inst.dest, inst.src1, inst.src2);
gpr.SpillLock(inst.dest, inst.src1, inst.src2);
gpr.MapReg(inst.src1);
gpr.MapReg(inst.src2);
// It's still fine to sign extend, the biggest just get even bigger.
NormalizeSrc12(inst, &lhs, &rhs, SCRATCH1, SCRATCH2, true);
gpr.MapReg(inst.dest, MIPSMap::NOINIT | MIPSMap::MARK_NORM32);
gpr.ReleaseSpillLock(inst.dest, inst.src1, inst.src2);
SLTU(gpr.R(inst.dest), lhs, rhs);
gpr.MarkDirty(gpr.R(inst.dest), true);
break;
case IROp::SltUConst:
// Not using the NORM32 flag so we don't confuse ourselves on overlap.
gpr.MapDirtyIn(inst.dest, inst.src1);
if (inst.constant == 0) {
gpr.SetImm(inst.dest, 0);
} else {
gpr.SpillLock(inst.dest, inst.src1);
gpr.MapReg(inst.src1);
NormalizeSrc1(inst, &lhs, SCRATCH1, false);
gpr.MapReg(inst.dest, MIPSMap::NOINIT | MIPSMap::MARK_NORM32);
gpr.ReleaseSpillLock(inst.dest, inst.src1);
// We sign extend because we're comparing against something normalized.
// It's also the most efficient to set.
@@ -425,8 +436,6 @@ void RiscVJit::CompIR_Compare(IRInst inst) {
LI(SCRATCH2, (int32_t)inst.constant);
SLTU(gpr.R(inst.dest), lhs, SCRATCH2);
}
gpr.MarkDirty(gpr.R(inst.dest), true);
}
break;