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Don't fold "ptrtoint GV to bool" since this should be doing a truncate not 

a comparison against zero. Instead fold setne(GV,null) and seteq(GV,null)
to ConstantBool::True or ConstantBool::False, respectively.

llvm-svn: 32060
This commit is contained in:
Reid Spencer 2006-12-01 03:56:30 +00:00
parent 30477cd88e
commit 6f05d73938
1 changed files with 27 additions and 7 deletions
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34
llvm/lib/VMCore/ConstantFolding.cpp
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@ -893,11 +893,6 @@ Constant *llvm::ConstantFoldCastInstruction(unsigned opc, const Constant *V,
break;
case Instruction::PtrToInt:
// Cast of a global address to boolean is always true.
if (const GlobalValue *GV = dyn_cast<GlobalValue>(V)) {
if (DestTy == Type::BoolTy && !GV->hasExternalWeakLinkage())
return ConstantBool::getTrue();
}
break;
case Instruction::BitCast:
// Check to see if we are casting a pointer to an aggregate to a pointer to
@ -1371,10 +1366,35 @@ Constant *llvm::ConstantFoldBinaryInstruction(unsigned Opcode,
case Instruction::Shl: C = ConstRules::get(V1, V2).shl(V1, V2); break;
case Instruction::LShr: C = ConstRules::get(V1, V2).lshr(V1, V2); break;
case Instruction::AShr: C = ConstRules::get(V1, V2).ashr(V1, V2); break;
case Instruction::SetEQ: C = ConstRules::get(V1, V2).equalto(V1, V2); break;
case Instruction::SetEQ:
// SetEQ(null,GV) -> false
if (V1->isNullValue()) {
if (const GlobalValue *GV = dyn_cast<GlobalValue>(V2))
if (!GV->hasExternalWeakLinkage())
return ConstantBool::getFalse();
// SetEQ(GV,null) -> false
} else if (V2->isNullValue()) {
if (const GlobalValue *GV = dyn_cast<GlobalValue>(V1))
if (!GV->hasExternalWeakLinkage())
return ConstantBool::getFalse();
}
C = ConstRules::get(V1, V2).equalto(V1, V2);
break;
case Instruction::SetLT: C = ConstRules::get(V1, V2).lessthan(V1, V2);break;
case Instruction::SetGT: C = ConstRules::get(V1, V2).lessthan(V2, V1);break;
case Instruction::SetNE: // V1 != V2 === !(V1 == V2)
case Instruction::SetNE:
// SetNE(null,GV) -> true
if (V1->isNullValue()) {
if (const GlobalValue *GV = dyn_cast<GlobalValue>(V2))
if (!GV->hasExternalWeakLinkage())
return ConstantBool::getTrue();
// SetNE(GV,null) -> true
} else if (V2->isNullValue()) {
if (const GlobalValue *GV = dyn_cast<GlobalValue>(V1))
if (!GV->hasExternalWeakLinkage())
return ConstantBool::getTrue();
}
// V1 != V2 === !(V1 == V2)
C = ConstRules::get(V1, V2).equalto(V1, V2);
if (C) return ConstantExpr::getNot(C);
break;