+/// Given operands for an FAdd, see if we can fold the result. If not, this
+/// returns null.
+static Value *SimplifyFAddInst(Value *Op0, Value *Op1, FastMathFlags FMF,
+ const Query &Q, unsigned MaxRecurse) {
+ if (Constant *CLHS = dyn_cast<Constant>(Op0)) {
+ if (Constant *CRHS = dyn_cast<Constant>(Op1)) {
+ Constant *Ops[] = { CLHS, CRHS };
+ return ConstantFoldInstOperands(Instruction::FAdd, CLHS->getType(),
+ Ops, Q.TD, Q.TLI);
+ }
+
+ // Canonicalize the constant to the RHS.
+ std::swap(Op0, Op1);
+ }
+
+ // fadd X, -0 ==> X
+ if (match(Op1, m_NegZero()))
+ return Op0;
+
+ // fadd X, 0 ==> X, when we know X is not -0
+ if (match(Op1, m_Zero()) &&
+ (FMF.noSignedZeros() || CannotBeNegativeZero(Op0)))
+ return Op0;
+
+ // fadd [nnan ninf] X, (fsub [nnan ninf] 0, X) ==> 0
+ // where nnan and ninf have to occur at least once somewhere in this
+ // expression
+ Value *SubOp = 0;
+ if (match(Op1, m_FSub(m_AnyZero(), m_Specific(Op0))))
+ SubOp = Op1;
+ else if (match(Op0, m_FSub(m_AnyZero(), m_Specific(Op1))))
+ SubOp = Op0;
+ if (SubOp) {
+ Instruction *FSub = cast<Instruction>(SubOp);
+ if ((FMF.noNaNs() || FSub->hasNoNaNs()) &&
+ (FMF.noInfs() || FSub->hasNoInfs()))
+ return Constant::getNullValue(Op0->getType());
+ }
+
+ return 0;
+}
+
+/// Given operands for an FSub, see if we can fold the result. If not, this
+/// returns null.
+static Value *SimplifyFSubInst(Value *Op0, Value *Op1, FastMathFlags FMF,
+ const Query &Q, unsigned MaxRecurse) {
+ if (Constant *CLHS = dyn_cast<Constant>(Op0)) {
+ if (Constant *CRHS = dyn_cast<Constant>(Op1)) {
+ Constant *Ops[] = { CLHS, CRHS };
+ return ConstantFoldInstOperands(Instruction::FSub, CLHS->getType(),
+ Ops, Q.TD, Q.TLI);
+ }
+ }
+
+ // fsub X, 0 ==> X
+ if (match(Op1, m_Zero()))
+ return Op0;
+
+ // fsub X, -0 ==> X, when we know X is not -0
+ if (match(Op1, m_NegZero()) &&
+ (FMF.noSignedZeros() || CannotBeNegativeZero(Op0)))
+ return Op0;
+
+ // fsub 0, (fsub -0.0, X) ==> X
+ Value *X;
+ if (match(Op0, m_AnyZero())) {
+ if (match(Op1, m_FSub(m_NegZero(), m_Value(X))))
+ return X;
+ if (FMF.noSignedZeros() && match(Op1, m_FSub(m_AnyZero(), m_Value(X))))
+ return X;
+ }
+
+ // fsub nnan ninf x, x ==> 0.0
+ if (FMF.noNaNs() && FMF.noInfs() && Op0 == Op1)
+ return Constant::getNullValue(Op0->getType());
+
+ return 0;
+}
+