[llvm] [InstCombine] Simplify select if it combinated and/or/xor (PR #73362)
via llvm-commits
llvm-commits at lists.llvm.org
Wed Feb 14 21:41:17 PST 2024
================
@@ -1672,6 +1672,138 @@ static Value *foldSelectInstWithICmpConst(SelectInst &SI, ICmpInst *ICI,
return nullptr;
}
+static Instruction *foldSelectICmpEq(SelectInst &SI, ICmpInst *ICI,
+ InstCombinerImpl &IC) {
+ ICmpInst::Predicate Pred = ICI->getPredicate();
+ if (!ICmpInst::isEquality(Pred))
+ return nullptr;
+
+ Value *TrueVal = SI.getTrueValue();
+ Value *FalseVal = SI.getFalseValue();
+ Value *CmpLHS = ICI->getOperand(0);
+ Value *CmpRHS = ICI->getOperand(1);
+
+ if (Pred == ICmpInst::ICMP_NE) {
+ Pred = ICmpInst::ICMP_EQ;
+ std::swap(TrueVal, FalseVal);
+ }
+
+ // Transform (X == C) ? X : Y -> (X == C) ? C : Y
+ // specific handling for Bitwise operation.
+ // https://alive2.llvm.org/ce/z/mW3eYR
+ // x&y -> (x|y) ^ (x^y) or (x|y) & ~(x^y)
+ // x|y -> (x&y) | (x^y) or (x&y) ^ (x^y)
+ // x^y -> (x|y) ^ (x&y) or (x|y) & ~(x&y)
+ Value *X, *Y;
+ if (!(match(CmpLHS, m_BitwiseLogic(m_Value(X), m_Value(Y)))) ||
+ !(match(TrueVal, m_BitwiseLogic(m_Specific(X), m_Specific(Y)))))
+ return nullptr;
+
+ Value *AllOnes = Constant::getAllOnesValue(TrueVal->getType());
+ Value *Null = Constant::getNullValue(TrueVal->getType());
+ Instruction *ISI = &cast<Instruction>(SI);
+ const unsigned AndOps = Instruction::And, OrOps = Instruction::Or,
+ XorOps = Instruction::Xor, NoOps = 0;
+ enum NotMask { None = 0, NotInner, NotRHS };
+
+ auto matchFalseVal = [&](Value *FalseVal, Value *CmpRHS, Value *X, Value *Y,
+ unsigned OuterOpc, unsigned InnerOpc,
+ unsigned NotMask) {
+ auto matchInner = m_c_BinOp(InnerOpc, m_Specific(X), m_Specific(Y));
+ if (OuterOpc == NoOps) {
+ if (match(CmpRHS, m_Zero()))
+ return match(FalseVal, matchInner);
+ else
+ return false;
+ }
+
+ if (NotMask == NotInner) {
+ return match(FalseVal,
+ m_c_BinOp(OuterOpc, m_Not(matchInner), m_Specific(CmpRHS)));
+ } else if (NotMask == NotRHS) {
+ return match(FalseVal,
+ m_c_BinOp(OuterOpc, matchInner, m_Not(m_Specific(CmpRHS))));
+ } else {
+ return match(FalseVal,
+ m_c_BinOp(OuterOpc, matchInner, m_Specific(CmpRHS)));
+ }
+ };
+
+ // https://alive2.llvm.org/ce/z/rw7XWv
+ // (X&Y)==C ? X|Y : X^Y -> (X^Y)|C : X^Y or (X^Y)^ C : X^Y
+ // (X&Y)==C ? X^Y : X|Y -> (X|Y)^C : X|Y or (X|Y)&~C : X|Y
+ // if C== 0, X^Y:X|Y -> ~0&X|Y:X|Y -> X|Y, X|Y:X^Y -> 0|X^Y:X^Y -> X^Y
+ // if C==-1, X^Y:X|Y ->~-1&X|Y:X|Y -> 0:X|Y, X|Y:X^Y -> -1|X^Y:X^Y ->-1:X^Y
+ // otherwise,
+ // X|Y:(X^Y)|C -> (X^Y)|C, X|Y:(X^Y)^C -> (X^Y)|C,
+ // X^Y:(X|Y)&~C -> (X|Y)&~C, X^Y:(X|Y)^C -> (X|Y)^C
+ if (match(CmpLHS, m_And(m_Value(X), m_Value(Y)))) {
+ if (match(TrueVal, m_c_Or(m_Specific(X), m_Specific(Y)))) {
+ if (matchFalseVal(FalseVal, CmpRHS, X, Y, NoOps, XorOps, None) ||
+ matchFalseVal(FalseVal, CmpRHS, X, Y, OrOps, XorOps, None) ||
+ matchFalseVal(FalseVal, CmpRHS, X, Y, XorOps, XorOps, None))
+ return IC.replaceInstUsesWith(*ISI, FalseVal);
+ else if (match(CmpRHS, m_AllOnes()))
+ return IC.replaceOperand(SI, 1, AllOnes);
+ } else if (match(TrueVal, m_c_Xor(m_Specific(X), m_Specific(Y)))) {
+ if (matchFalseVal(FalseVal, CmpRHS, X, Y, NoOps, OrOps, None) ||
+ matchFalseVal(FalseVal, CmpRHS, X, Y, XorOps, OrOps, None) ||
+ matchFalseVal(FalseVal, CmpRHS, X, Y, AndOps, OrOps, NotRHS))
+ return IC.replaceInstUsesWith(*ISI, FalseVal);
+ else if (match(CmpRHS, m_AllOnes()))
+ return IC.replaceOperand(SI, 1, Null);
+ }
+ }
+
+ // https://alive2.llvm.org/ce/z/5yaUzR
+ // (X|Y)==C ? X&Y : X^Y -> (X^Y)^C : X^Y or ~(X^Y)&C : X^Y
+ // (X|Y)==C ? X^Y : X&Y -> (X&Y)^C : X&Y or ~(X&Y)&C : X&Y
+ // if C == 0, (X BitwiseOp Y) : FalseVal -> 0:FalseVal
+ // if C == 0, X&Y:X^Y -> 0^(X^Y):X^Y -> X^Y, X^Y:X&Y -> 0^(X&Y):X&Y -> X&Y
+ // X&Y|(X^Y)^C -> (X^Y)^C, X&Y:~(X^Y)&C -> ~(X^Y)&C
+ // X^Y:(X&Y)^C -> (X&Y)^C, X^Y:~(X&Y)&C -> ~(X&Y)&C
+ if (match(CmpLHS, m_Or(m_Value(X), m_Value(Y)))) {
+ if (match(TrueVal, m_c_And(m_Specific(X), m_Specific(Y)))) {
+ if (matchFalseVal(FalseVal, CmpRHS, X, Y, NoOps, XorOps, None) ||
+ matchFalseVal(FalseVal, CmpRHS, X, Y, XorOps, XorOps, None) ||
+ matchFalseVal(FalseVal, CmpRHS, X, Y, AndOps, XorOps, NotInner))
+ return IC.replaceInstUsesWith(*ISI, FalseVal);
+ } else if (match(TrueVal, m_c_Xor(m_Specific(X), m_Specific(Y)))) {
+ if (matchFalseVal(FalseVal, CmpRHS, X, Y, NoOps, AndOps, None) ||
+ matchFalseVal(FalseVal, CmpRHS, X, Y, XorOps, AndOps, None) ||
+ matchFalseVal(FalseVal, CmpRHS, X, Y, AndOps, AndOps, NotInner))
+ return IC.replaceInstUsesWith(*ISI, FalseVal);
+ } else if (match(TrueVal, m_BitwiseLogic(m_Specific(X), m_Specific(Y))) &&
+ match(CmpRHS, m_Zero()))
+ return IC.replaceOperand(SI, 1, Null);
+ }
+
+ // https://alive2.llvm.org/ce/z/dA9Hy-
+ // (X^Y)==C ? X&Y : X|Y -> (X|Y)^C : X|Y or (X|Y)&~C : X|Y
+ // (X^Y)==C ? X|Y : X&Y -> (X&Y)|C : X&Y or (X&Y)^ C : X&Y
+ // X^Y==-1 ? X&Y:~(X|Y) -> (X|Y)^-1:~(X|Y)-> ~(X|Y)
+ // X^Y==-1 ? X|Y: X^Y -> (X&Y)|-1: X^Y -> -1:X^Y
+ // X&Y:(X|Y)^C -> (X|Y)^C, X&Y:(X|Y)&~C -> (X|Y)&~C
+ // X|Y:(X&Y)|C -> (X&Y)|C, X|Y:(X&Y)^C -> (X&Y)^C
+ if (match(CmpLHS, m_Xor(m_Value(X), m_Value(Y)))) {
+ if ((match(TrueVal, m_c_And(m_Specific(X), m_Specific(Y))))) {
+ if (matchFalseVal(FalseVal, CmpRHS, X, Y, XorOps, OrOps, None) ||
+ matchFalseVal(FalseVal, CmpRHS, X, Y, XorOps, OrOps, None) ||
+ matchFalseVal(FalseVal, CmpRHS, X, Y, AndOps, OrOps, NotRHS))
+ return IC.replaceInstUsesWith(*ISI, FalseVal);
+ } else if (match(TrueVal, m_c_Or(m_Specific(X), m_Specific(Y)))) {
+ if (matchFalseVal(FalseVal, CmpRHS, X, Y, OrOps, AndOps, None) ||
+ matchFalseVal(FalseVal, CmpRHS, X, Y, OrOps, AndOps, None) ||
----------------
ParkHanbum wrote:
sorry about that. fixed it.
https://github.com/llvm/llvm-project/pull/73362
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