add support for special values NotaNumber, MinusZero
MODIFY
instrumentation/split-compares-pass.so.cc
instrumentation/split-compares-pass.so.cc
@@ -882,6 +882,7 @@ size_t SplitComparesTransform::splitFPCompares(Module &M) {
// BUG FIXME TODO: u64 does not work for > 64 bit ... e.g. 80 and 128 bit
if (sizeInBits > 64) { continue; }
+ IntegerType *intType = IntegerType::get(C, op_size);
const unsigned int precision = sizeInBits == 32 ? 24
: sizeInBits == 64 ? 53
: sizeInBits == 128 ? 113
@@ -913,14 +914,99 @@ size_t SplitComparesTransform::splitFPCompares(Module &M) {
BasicBlock *end_bb = bb->splitBasicBlock(BasicBlock::iterator(FcmpInst));
/* create the integers from floats directly */
- Instruction *b_op0, *b_op1;
- b_op0 = CastInst::Create(Instruction::BitCast, op0,
+ Instruction *bpre_op0, *bpre_op1;
+ bpre_op0 = CastInst::Create(Instruction::BitCast, op0,
IntegerType::get(C, op_size));
- bb->getInstList().insert(BasicBlock::iterator(bb->getTerminator()), b_op0);
+ bb->getInstList().insert(BasicBlock::iterator(bb->getTerminator()), bpre_op0);
- b_op1 = CastInst::Create(Instruction::BitCast, op1,
+ bpre_op1 = CastInst::Create(Instruction::BitCast, op1,
IntegerType::get(C, op_size));
- bb->getInstList().insert(BasicBlock::iterator(bb->getTerminator()), b_op1);
+ bb->getInstList().insert(BasicBlock::iterator(bb->getTerminator()), bpre_op1);
+
+
+ /* Check if any operand is NaN.
+ * If so, all comparisons except unequal (which yields true) yield false */
+
+ /* build mask for NaN */
+ const unsigned long long NaN_lowend = mask_exponent << precision;
+ // errs() << "Fractions: IntFractionTy size " <<
+ // IntFractionTy->getPrimitiveSizeInBits() << ", op_size " << op_size <<
+ // ", mask_fraction 0x";
+ // errs().write_hex(mask_fraction);
+ // errs() << ", precision " << precision <<
+ // ", NaN_lowend 0x";
+ // errs().write_hex(NaN_lowend); errs() << "\n";
+
+ /* Check op0 for NaN */
+ /* Shift left 1 Bit, ignore sign bit */
+ Instruction *nan_op0, *nan_op1;
+ nan_op0 = BinaryOperator::Create(
+ Instruction::Shl, bpre_op0,
+ ConstantInt::get(bpre_op0->getType(), 1));
+ bb->getInstList().insert(BasicBlock::iterator(bb->getTerminator()), nan_op0);
+
+ /* compare to NaN interval */
+ Instruction *is_op0_nan =
+ CmpInst::Create(Instruction::ICmp, CmpInst::ICMP_UGT, nan_op0, ConstantInt::get(intType, NaN_lowend) );
+ bb->getInstList().insert(BasicBlock::iterator(bb->getTerminator()),
+ is_op0_nan);
+
+ /* Check op1 for NaN */
+ /* Shift right 1 Bit, ignore sign bit */
+ nan_op1 = BinaryOperator::Create(
+ Instruction::Shl, bpre_op1,
+ ConstantInt::get(bpre_op1->getType(), 1));
+ bb->getInstList().insert(BasicBlock::iterator(bb->getTerminator()), nan_op1);
+
+ /* compare to NaN interval */
+ Instruction *is_op1_nan =
+ CmpInst::Create(Instruction::ICmp, CmpInst::ICMP_UGT, nan_op1, ConstantInt::get(intType, NaN_lowend) );
+ bb->getInstList().insert(BasicBlock::iterator(bb->getTerminator()),
+ is_op1_nan);
+
+ /* combine checks */
+ Instruction *is_nan = BinaryOperator::Create(
+ Instruction::Or, is_op0_nan, is_op1_nan);
+ bb->getInstList().insert(BasicBlock::iterator(bb->getTerminator()),
+ is_nan);
+
+ /* the result of the comparison, when at least one op is NaN
+ is true only for the "NOT EQUAL" predicates. */
+ bool NaNcmp_result =
+ FcmpInst->getPredicate() == CmpInst::FCMP_ONE ||
+ FcmpInst->getPredicate() == CmpInst::FCMP_UNE;
+
+ BasicBlock *nonan_bb =
+ BasicBlock::Create(C, "noNaN", end_bb->getParent(), end_bb);
+
+ BranchInst::Create(end_bb, nonan_bb);
+
+ auto term = bb->getTerminator();
+ /* if no operand is NaN goto nonan_bb else to handleNaN_bb */
+ BranchInst::Create(end_bb, nonan_bb, is_nan, bb);
+ term->eraseFromParent();
+
+ /*** now working in nonan_bb ***/
+
+ /* Treat -0.0 as equal to +0.0, that is for -0.0 make it +0.0 */
+ Instruction *b_op0, *b_op1;
+ Instruction *isMzero_op0, *isMzero_op1;
+ const unsigned long long MinusZero = 1UL << (sizeInBits - 1U);
+ const unsigned long long PlusZero = 0;
+
+ isMzero_op0 =
+ CmpInst::Create(Instruction::ICmp, CmpInst::ICMP_EQ, bpre_op0, ConstantInt::get(intType, MinusZero));
+ nonan_bb->getInstList().insert(BasicBlock::iterator(nonan_bb->getTerminator()), isMzero_op0);
+
+ isMzero_op1 =
+ CmpInst::Create(Instruction::ICmp, CmpInst::ICMP_EQ, bpre_op1, ConstantInt::get(intType, MinusZero));
+ nonan_bb->getInstList().insert(BasicBlock::iterator(nonan_bb->getTerminator()), isMzero_op1);
+
+ b_op0 = SelectInst::Create(isMzero_op0, ConstantInt::get(intType, PlusZero), bpre_op0);
+ nonan_bb->getInstList().insert(BasicBlock::iterator(nonan_bb->getTerminator()), b_op0);
+
+ b_op1 = SelectInst::Create(isMzero_op1, ConstantInt::get(intType, PlusZero), bpre_op1);
+ nonan_bb->getInstList().insert(BasicBlock::iterator(nonan_bb->getTerminator()), b_op1);
/* isolate signs of value of floating point type */
@@ -931,21 +1017,21 @@ size_t SplitComparesTransform::splitFPCompares(Module &M) {
s_s0 =
BinaryOperator::Create(Instruction::LShr, b_op0,
ConstantInt::get(b_op0->getType(), op_size - 1));
- bb->getInstList().insert(BasicBlock::iterator(bb->getTerminator()), s_s0);
+ nonan_bb->getInstList().insert(BasicBlock::iterator(nonan_bb->getTerminator()), s_s0);
t_s0 = new TruncInst(s_s0, Int1Ty);
- bb->getInstList().insert(BasicBlock::iterator(bb->getTerminator()), t_s0);
+ nonan_bb->getInstList().insert(BasicBlock::iterator(nonan_bb->getTerminator()), t_s0);
s_s1 =
BinaryOperator::Create(Instruction::LShr, b_op1,
ConstantInt::get(b_op1->getType(), op_size - 1));
- bb->getInstList().insert(BasicBlock::iterator(bb->getTerminator()), s_s1);
+ nonan_bb->getInstList().insert(BasicBlock::iterator(nonan_bb->getTerminator()), s_s1);
t_s1 = new TruncInst(s_s1, Int1Ty);
- bb->getInstList().insert(BasicBlock::iterator(bb->getTerminator()), t_s1);
+ nonan_bb->getInstList().insert(BasicBlock::iterator(nonan_bb->getTerminator()), t_s1);
/* compare of the sign bits */
icmp_sign_bit =
CmpInst::Create(Instruction::ICmp, CmpInst::ICMP_EQ, t_s0, t_s1);
- bb->getInstList().insert(BasicBlock::iterator(bb->getTerminator()),
+ nonan_bb->getInstList().insert(BasicBlock::iterator(nonan_bb->getTerminator()),
icmp_sign_bit);
/* create a new basic block which is executed if the signedness bits are
@@ -962,9 +1048,9 @@ size_t SplitComparesTransform::splitFPCompares(Module &M) {
BranchInst::Create(end_bb, middle_bb);
- auto term = bb->getTerminator();
+ term = nonan_bb->getTerminator();
/* if the signs are different goto end_bb else to signequal_bb */
- BranchInst::Create(signequal_bb, end_bb, icmp_sign_bit, bb);
+ BranchInst::Create(signequal_bb, end_bb, icmp_sign_bit, nonan_bb);
term->eraseFromParent();
/* insert code for equal signs */
@@ -1261,7 +1347,7 @@ size_t SplitComparesTransform::splitFPCompares(Module &M) {
}
- PHINode *PN = PHINode::Create(Int1Ty, 3, "");
+ PHINode *PN = PHINode::Create(Int1Ty, 4, "");
switch (FcmpInst->getPredicate()) {
@@ -1269,37 +1355,45 @@ size_t SplitComparesTransform::splitFPCompares(Module &M) {
case CmpInst::FCMP_OEQ:
/* unequal signs cannot be equal values */
/* goto false branch */
- PN->addIncoming(ConstantInt::get(Int1Ty, 0), bb);
+ PN->addIncoming(ConstantInt::get(Int1Ty, 0), nonan_bb);
/* unequal exponents cannot be equal values, too */
PN->addIncoming(ConstantInt::get(Int1Ty, 0), signequal_bb);
/* fractions comparison */
PN->addIncoming(icmp_fraction_result, middle2_bb);
+ /* NaNs */
+ PN->addIncoming(ConstantInt::get(Int1Ty, NaNcmp_result), bb);
break;
case CmpInst::FCMP_ONE:
case CmpInst::FCMP_UNE:
/* unequal signs are unequal values */
/* goto true branch */
- PN->addIncoming(ConstantInt::get(Int1Ty, 1), bb);
+ PN->addIncoming(ConstantInt::get(Int1Ty, 1), nonan_bb);
/* unequal exponents are unequal values, too */
PN->addIncoming(icmp_exponent_result, signequal_bb);
/* fractions comparison */
PN->addIncoming(icmp_fraction_result, middle2_bb);
+ /* NaNs */
+ PN->addIncoming(ConstantInt::get(Int1Ty, NaNcmp_result), bb);
break;
case CmpInst::FCMP_OGT:
case CmpInst::FCMP_UGT:
/* if op1 is negative goto true branch,
else go on comparing */
- PN->addIncoming(t_s1, bb);
+ PN->addIncoming(t_s1, nonan_bb);
PN->addIncoming(icmp_exponent_result, signequal2_bb);
PN->addIncoming(PN2, middle2_bb);
+ /* NaNs */
+ PN->addIncoming(ConstantInt::get(Int1Ty, NaNcmp_result), bb);
break;
case CmpInst::FCMP_OLT:
case CmpInst::FCMP_ULT:
/* if op0 is negative goto true branch,
else go on comparing */
- PN->addIncoming(t_s0, bb);
+ PN->addIncoming(t_s0, nonan_bb);
PN->addIncoming(icmp_exponent_result, signequal2_bb);
PN->addIncoming(PN2, middle2_bb);
+ /* NaNs */
+ PN->addIncoming(ConstantInt::get(Int1Ty, NaNcmp_result), bb);
break;
default:
continue;
@@ -1341,19 +1435,16 @@ bool SplitComparesTransform::runOnModule(Module &M) {
if (enableFPSplit) {
+ simplifyFPCompares(M);
count = splitFPCompares(M);
- /*
- if (!be_quiet) {
+ if (!be_quiet && !debug) {
errs() << "Split-floatingpoint-compare-pass: " << count
- << " FP comparisons split\n";
+ << " FP comparisons splitted\n";
}
- */
- simplifyFPCompares(M);
-
}
std::vector<CmpInst *> worklist;

add support for special values NotaNumber, MinusZero