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| author | Reid Spencer <rspencer@reidspencer.com> | 2007-03-23 05:33:23 +0000 |
|---|---|---|
| committer | Reid Spencer <rspencer@reidspencer.com> | 2007-03-23 05:33:23 +0000 |
| commit | b8f1c1657f1b63f92957c5b1c5a4e26e4945c34d (patch) | |
| tree | 6bc837c298cdd4082a9d97631b702db984dd94ef /lib/VMCore | |
| parent | f62cc9f9e5ddd95adcb0f7317ef4458bbdbebffd (diff) | |
| download | external_llvm-b8f1c1657f1b63f92957c5b1c5a4e26e4945c34d.zip external_llvm-b8f1c1657f1b63f92957c5b1c5a4e26e4945c34d.tar.gz external_llvm-b8f1c1657f1b63f92957c5b1c5a4e26e4945c34d.tar.bz2 | |
Fix constant fold of div by zero and rem by zero to match IEEE 754
requirements. We must return NaN in some cases and correctly signed
infinity in other cases. Passes CFP2006 (not that that says much).
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@35277 91177308-0d34-0410-b5e6-96231b3b80d8
Diffstat (limited to 'lib/VMCore')
| -rw-r--r-- | lib/VMCore/ConstantFold.cpp | 26 |
1 files changed, 18 insertions, 8 deletions
diff --git a/lib/VMCore/ConstantFold.cpp b/lib/VMCore/ConstantFold.cpp index 05a7588..d7e5195 100644 --- a/lib/VMCore/ConstantFold.cpp +++ b/lib/VMCore/ConstantFold.cpp @@ -651,17 +651,27 @@ Constant *llvm::ConstantFoldBinaryInstruction(unsigned Opcode, case Instruction::Mul: return ConstantFP::get(CFP1->getType(), C1Val * C2Val); case Instruction::FDiv: - if (CFP2->isExactlyValue(0.0)) - return ConstantFP::get(CFP1->getType(), - std::numeric_limits<double>::infinity()); - if (CFP2->isExactlyValue(-0.0)) - return ConstantFP::get(CFP1->getType(), - -std::numeric_limits<double>::infinity()); + if (CFP2->isExactlyValue(0.0) || CFP2->isExactlyValue(-0.0)) + if (CFP1->isExactlyValue(0.0) || CFP1->isExactlyValue(-0.0)) + // IEEE 754, Section 7.1, #4 + return ConstantFP::get(CFP1->getType(), + std::numeric_limits<double>::quiet_NaN()); + else if (CFP2->isExactlyValue(-0.0) || C1Val < 0.0) + // IEEE 754, Section 7.2, negative infinity case + return ConstantFP::get(CFP1->getType(), + -std::numeric_limits<double>::infinity()); + else + // IEEE 754, Section 7.2, positive infinity case + return ConstantFP::get(CFP1->getType(), + std::numeric_limits<double>::infinity()); return ConstantFP::get(CFP1->getType(), C1Val / C2Val); case Instruction::FRem: - if (CFP2->isNullValue()) - return 0; + if (CFP2->isExactlyValue(0.0) || CFP2->isExactlyValue(-0.0)) + // IEEE 754, Section 7.1, #5 + return ConstantFP::get(CFP1->getType(), + std::numeric_limits<double>::quiet_NaN()); return ConstantFP::get(CFP1->getType(), std::fmod(C1Val, C2Val)); + } } } else if (const ConstantVector *CP1 = dyn_cast<ConstantVector>(C1)) { |