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-rw-r--r--lib/VMCore/BasicBlock.cpp20
-rw-r--r--lib/VMCore/ConstantFold.cpp37
-rw-r--r--lib/VMCore/Constants.cpp31
3 files changed, 74 insertions, 14 deletions
diff --git a/lib/VMCore/BasicBlock.cpp b/lib/VMCore/BasicBlock.cpp
index 7d47044..70265c8 100644
--- a/lib/VMCore/BasicBlock.cpp
+++ b/lib/VMCore/BasicBlock.cpp
@@ -147,6 +147,26 @@ Instruction* BasicBlock::getFirstNonPHIOrDbg() {
return &*i;
}
+Instruction* BasicBlock::getFirstNonPHIOrDbgOrLifetime() {
+ // All valid basic blocks should have a terminator,
+ // which is not a PHINode. If we have an invalid basic
+ // block we'll get an assertion failure when dereferencing
+ // a past-the-end iterator.
+ BasicBlock::iterator i = begin();
+ for (;; ++i) {
+ if (isa<PHINode>(i) || isa<DbgInfoIntrinsic>(i))
+ continue;
+
+ const IntrinsicInst *II = dyn_cast<IntrinsicInst>(i);
+ if (!II)
+ break;
+ if (II->getIntrinsicID() != Intrinsic::lifetime_start &&
+ II->getIntrinsicID() != Intrinsic::lifetime_end)
+ break;
+ }
+ return &*i;
+}
+
void BasicBlock::dropAllReferences() {
for(iterator I = begin(), E = end(); I != E; ++I)
I->dropAllReferences();
diff --git a/lib/VMCore/ConstantFold.cpp b/lib/VMCore/ConstantFold.cpp
index 579d356..b7a1350 100644
--- a/lib/VMCore/ConstantFold.cpp
+++ b/lib/VMCore/ConstantFold.cpp
@@ -730,9 +730,12 @@ Constant *llvm::ConstantFoldSelectInstruction(Constant *Cond,
}
+ if (isa<UndefValue>(Cond)) {
+ if (isa<UndefValue>(V1)) return V1;
+ return V2;
+ }
if (isa<UndefValue>(V1)) return V2;
if (isa<UndefValue>(V2)) return V1;
- if (isa<UndefValue>(Cond)) return V1;
if (V1 == V2) return V1;
if (ConstantExpr *TrueVal = dyn_cast<ConstantExpr>(V1)) {
@@ -1014,20 +1017,38 @@ Constant *llvm::ConstantFoldBinaryInstruction(unsigned Opcode,
case Instruction::Add:
case Instruction::Sub:
return UndefValue::get(C1->getType());
- case Instruction::Mul:
case Instruction::And:
+ if (isa<UndefValue>(C1) && isa<UndefValue>(C2)) // undef & undef -> undef
+ return C1;
+ return Constant::getNullValue(C1->getType()); // undef & X -> 0
+ case Instruction::Mul: {
+ ConstantInt *CI;
+ // X * undef -> undef if X is odd or undef
+ if (((CI = dyn_cast<ConstantInt>(C1)) && CI->getValue()[0]) ||
+ ((CI = dyn_cast<ConstantInt>(C2)) && CI->getValue()[0]) ||
+ (isa<UndefValue>(C1) && isa<UndefValue>(C2)))
+ return UndefValue::get(C1->getType());
+
+ // X * undef -> 0 otherwise
return Constant::getNullValue(C1->getType());
+ }
case Instruction::UDiv:
case Instruction::SDiv:
+ // undef / 1 -> undef
+ if (Opcode == Instruction::UDiv || Opcode == Instruction::SDiv)
+ if (ConstantInt *CI2 = dyn_cast<ConstantInt>(C2))
+ if (CI2->isOne())
+ return C1;
+ // FALL THROUGH
case Instruction::URem:
case Instruction::SRem:
if (!isa<UndefValue>(C2)) // undef / X -> 0
return Constant::getNullValue(C1->getType());
return C2; // X / undef -> undef
case Instruction::Or: // X | undef -> -1
- if (const VectorType *PTy = dyn_cast<VectorType>(C1->getType()))
- return Constant::getAllOnesValue(PTy);
- return Constant::getAllOnesValue(C1->getType());
+ if (isa<UndefValue>(C1) && isa<UndefValue>(C2)) // undef | undef -> undef
+ return C1;
+ return Constant::getAllOnesValue(C1->getType()); // undef | X -> ~0
case Instruction::LShr:
if (isa<UndefValue>(C2) && isa<UndefValue>(C1))
return C1; // undef lshr undef -> undef
@@ -1041,6 +1062,8 @@ Constant *llvm::ConstantFoldBinaryInstruction(unsigned Opcode,
else
return C1; // X ashr undef --> X
case Instruction::Shl:
+ if (isa<UndefValue>(C2) && isa<UndefValue>(C1))
+ return C1; // undef shl undef -> undef
// undef << X -> 0 or X << undef -> 0
return Constant::getNullValue(C1->getType());
}
@@ -1831,7 +1854,9 @@ Constant *llvm::ConstantFoldCompareInstruction(unsigned short pred,
if (isa<UndefValue>(C1) || isa<UndefValue>(C2)) {
// For EQ and NE, we can always pick a value for the undef to make the
// predicate pass or fail, so we can return undef.
- if (ICmpInst::isEquality(ICmpInst::Predicate(pred)))
+ // Also, if both operands are undef, we can return undef.
+ if (ICmpInst::isEquality(ICmpInst::Predicate(pred)) ||
+ (isa<UndefValue>(C1) && isa<UndefValue>(C2)))
return UndefValue::get(ResultTy);
// Otherwise, pick the same value as the non-undef operand, and fold
// it to true or false.
diff --git a/lib/VMCore/Constants.cpp b/lib/VMCore/Constants.cpp
index 87f2fe6..4e6e64d 100644
--- a/lib/VMCore/Constants.cpp
+++ b/lib/VMCore/Constants.cpp
@@ -1011,17 +1011,32 @@ bool ConstantArray::isCString() const {
}
-/// getAsString - If the sub-element type of this array is i8
-/// then this method converts the array to an std::string and returns it.
-/// Otherwise, it asserts out.
+/// convertToString - Helper function for getAsString() and getAsCString().
+static std::string convertToString(const User *U, unsigned len)
+{
+ std::string Result;
+ Result.reserve(len);
+ for (unsigned i = 0; i != len; ++i)
+ Result.push_back((char)cast<ConstantInt>(U->getOperand(i))->getZExtValue());
+ return Result;
+}
+
+/// getAsString - If this array is isString(), then this method converts the
+/// array to an std::string and returns it. Otherwise, it asserts out.
///
std::string ConstantArray::getAsString() const {
assert(isString() && "Not a string!");
- std::string Result;
- Result.reserve(getNumOperands());
- for (unsigned i = 0, e = getNumOperands(); i != e; ++i)
- Result.push_back((char)cast<ConstantInt>(getOperand(i))->getZExtValue());
- return Result;
+ return convertToString(this, getNumOperands());
+}
+
+
+/// getAsCString - If this array is isCString(), then this method converts the
+/// array (without the trailing null byte) to an std::string and returns it.
+/// Otherwise, it asserts out.
+///
+std::string ConstantArray::getAsCString() const {
+ assert(isCString() && "Not a string!");
+ return convertToString(this, getNumOperands() - 1);
}
generated by cgit v1.1 at 2025-03-31 12:55:35 +0000