================
@@ -2732,100 +2732,114 @@ static Instruction *matchFunnelShift(Instruction &Or,
InstCombinerImpl &IC) {
// rotate matching code under visitSelect and visitTrunc?
unsigned Width = Or.getType()->getScalarSizeInBits();
- // First, find an or'd pair of opposite shifts:
- // or (lshr ShVal0, ShAmt0), (shl ShVal1, ShAmt1)
- BinaryOperator *Or0, *Or1;
- if (!match(Or.getOperand(0), m_BinOp(Or0)) ||
- !match(Or.getOperand(1), m_BinOp(Or1)))
- return nullptr;
-
- Value *ShVal0, *ShVal1, *ShAmt0, *ShAmt1;
- if (!match(Or0, m_OneUse(m_LogicalShift(m_Value(ShVal0), m_Value(ShAmt0))))
||
- !match(Or1, m_OneUse(m_LogicalShift(m_Value(ShVal1), m_Value(ShAmt1))))
||
- Or0->getOpcode() == Or1->getOpcode())
+ Instruction *Or0, *Or1;
+ if (!match(Or.getOperand(0), m_Instruction(Or0)) ||
+ !match(Or.getOperand(1), m_Instruction(Or1)))
return nullptr;
- // Canonicalize to or(shl(ShVal0, ShAmt0), lshr(ShVal1, ShAmt1)).
- if (Or0->getOpcode() == BinaryOperator::LShr) {
- std::swap(Or0, Or1);
- std::swap(ShVal0, ShVal1);
- std::swap(ShAmt0, ShAmt1);
- }
- assert(Or0->getOpcode() == BinaryOperator::Shl &&
- Or1->getOpcode() == BinaryOperator::LShr &&
- "Illegal or(shift,shift) pair");
-
- // Match the shift amount operands for a funnel shift pattern. This always
- // matches a subtraction on the R operand.
- auto matchShiftAmount = [&](Value *L, Value *R, unsigned Width) -> Value * {
- // Check for constant shift amounts that sum to the bitwidth.
- const APInt *LI, *RI;
- if (match(L, m_APIntAllowUndef(LI)) && match(R, m_APIntAllowUndef(RI)))
- if (LI->ult(Width) && RI->ult(Width) && (*LI + *RI) == Width)
- return ConstantInt::get(L->getType(), *LI);
-
- Constant *LC, *RC;
- if (match(L, m_Constant(LC)) && match(R, m_Constant(RC)) &&
- match(L, m_SpecificInt_ICMP(ICmpInst::ICMP_ULT, APInt(Width, Width)))
&&
- match(R, m_SpecificInt_ICMP(ICmpInst::ICMP_ULT, APInt(Width, Width)))
&&
- match(ConstantExpr::getAdd(LC, RC), m_SpecificIntAllowUndef(Width)))
- return ConstantExpr::mergeUndefsWith(LC, RC);
-
- // (shl ShVal, X) | (lshr ShVal, (Width - x)) iff X < Width.
- // We limit this to X < Width in case the backend re-expands the intrinsic,
- // and has to reintroduce a shift modulo operation (InstCombine might
remove
- // it after this fold). This still doesn't guarantee that the final codegen
- // will match this original pattern.
- if (match(R, m_OneUse(m_Sub(m_SpecificInt(Width), m_Specific(L))))) {
- KnownBits KnownL = IC.computeKnownBits(L, /*Depth*/ 0, &Or);
- return KnownL.getMaxValue().ult(Width) ? L : nullptr;
- }
+ bool IsFshl = true; // Sub on LSHR.
+ SmallVector<Value *, 3> FShiftArgs;
- // For non-constant cases, the following patterns currently only work for
- // rotation patterns.
- // TODO: Add general funnel-shift compatible patterns.
- if (ShVal0 != ShVal1)
+ // First, find an or'd pair of opposite shifts:
+ // or (lshr ShVal0, ShAmt0), (shl ShVal1, ShAmt1)
+ if (isa<BinaryOperator>(Or0) && isa<BinaryOperator>(Or1)) {
----------------
HaohaiWen wrote:
> This code seems new? Not that its wrong or anything.
I added this if statement in this patch.
It can be early returned in this patch, but I'd like to add another else if on
https://github.com/llvm/llvm-project/pull/68502/commits/5b3b1bbb5b263bc5711adde031d85b1461ccbab6.
If I removed this if statement, then I need to add the if back and indent the
code in the if statement on https://github.com/llvm/llvm-project/pull/68502.
This make the diff not clear.
https://github.com/llvm/llvm-project/pull/68474
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