diff --git a/Ghidra/Features/Decompiler/src/decompile/cpp/ruleaction.cc b/Ghidra/Features/Decompiler/src/decompile/cpp/ruleaction.cc index 74ec9ea4b7..6aec2546db 100644 --- a/Ghidra/Features/Decompiler/src/decompile/cpp/ruleaction.cc +++ b/Ghidra/Features/Decompiler/src/decompile/cpp/ruleaction.cc @@ -9476,6 +9476,26 @@ bool RuleIgnoreNan::checkBackForCompare(Varnode *floatVar,Varnode *root) return false; } +/// \brief Test if the given Varnode is produced by a NaN operation. +/// +/// The Varnode can be the direct or negated output of a NaN. +/// \param vn is the given Varnode +/// \return \b true if the Varnode is the output of the NaN +bool RuleIgnoreNan::isAnotherNan(Varnode *vn) + +{ + if (!vn->isWritten()) return false; + PcodeOp *op = vn->getDef(); + OpCode opc = op->code(); + if (opc == CPUI_BOOL_NEGATE) { + vn = op->getIn(0); + if (!vn->isWritten()) return false; + op = vn->getDef(); + opc = op->code(); + } + return (opc == CPUI_FLOAT_NAN); +} + /// \brief Test if a boolean expression incorporates a floating-point comparison, and remove the NaN data-flow if it does /// /// The given PcodeOp takes input from a NaN operation through a specific slot. We look for a floating-point comparison @@ -9497,35 +9517,34 @@ Varnode *RuleIgnoreNan::testForComparison(Varnode *floatVar,PcodeOp *op,int4 slo { if (op->code() == matchCode) { - Varnode *vn = op->getIn(1-slot); + Varnode *vn = op->getIn(1 - slot); if (checkBackForCompare(floatVar,vn)) { - data.opSetOpcode(op, CPUI_COPY); - data.opRemoveInput(op, 1); - data.opSetInput(op, vn, 0); + data.opSetOpcode(op,CPUI_COPY); + data.opRemoveInput(op,1); + data.opSetInput(op,vn,0); count += 1; } - return op->getOut(); - } - if (op->code() != CPUI_CBRANCH) - return (Varnode *)0; - BlockBasic *parent = op->getParent(); - bool flowToFromCompare = false; - PcodeOp *lastOp; - int4 outDir = (matchCode == CPUI_BOOL_OR) ? 0 : 1; - if (op->isBooleanFlip()) - outDir = 1 - outDir; - FlowBlock *outBranch = parent->getOut(outDir); - lastOp = outBranch->lastOp(); - if (lastOp != (PcodeOp *)0 && lastOp->code() == CPUI_CBRANCH) { - FlowBlock *otherBranch = parent->getOut(1-outDir); - if (outBranch->getOut(0) == otherBranch || outBranch->getOut(1) == otherBranch) { - if (checkBackForCompare(floatVar, lastOp->getIn(1))) - flowToFromCompare = true; + else if (isAnotherNan(vn)) { + return op->getOut(); } } - if (flowToFromCompare) { - data.opSetInput(op,data.newConstant(1, 0),1); // Treat result of NaN as false - count += 1; + else if (op->code() == CPUI_CBRANCH) { + BlockBasic *parent = op->getParent(); + PcodeOp *lastOp; + int4 outDir = (matchCode == CPUI_BOOL_OR) ? 0 : 1; + if (op->isBooleanFlip()) + outDir = 1 - outDir; + FlowBlock *outBranch = parent->getOut(outDir); + lastOp = outBranch->lastOp(); + if (lastOp != (PcodeOp*)0 && lastOp->code() == CPUI_CBRANCH) { + FlowBlock *otherBranch = parent->getOut(1 - outDir); + if (outBranch->getOut(0) == otherBranch || outBranch->getOut(1) == otherBranch) { + if (checkBackForCompare(floatVar,lastOp->getIn(1))) { + data.opSetInput(op,data.newConstant(1,(matchCode == CPUI_BOOL_OR) ? 0 : 1),1); + count += 1; + } + } + } } return (Varnode *)0; } diff --git a/Ghidra/Features/Decompiler/src/decompile/cpp/ruleaction.hh b/Ghidra/Features/Decompiler/src/decompile/cpp/ruleaction.hh index 97a7576ef1..b38af07623 100644 --- a/Ghidra/Features/Decompiler/src/decompile/cpp/ruleaction.hh +++ b/Ghidra/Features/Decompiler/src/decompile/cpp/ruleaction.hh @@ -1550,6 +1550,7 @@ public: class RuleIgnoreNan : public Rule { static bool checkBackForCompare(Varnode *floatVar,Varnode *root); + static bool isAnotherNan(Varnode *vn); static Varnode *testForComparison(Varnode *floatVar,PcodeOp *op,int4 slot,OpCode matchCode,int4 &count,Funcdata &data); public: RuleIgnoreNan(const string &g) : Rule( g, 0, "ignorenan") {} ///< Constructor