LLVM issues affecting LDC

This page lists issues in previous version of LLVM known to affect LDC.

Because of such issues, use of the latest LLVM release is highly recommended. If there are no recent LLVM packages for your distribution, see Building LDC from source. LLVM is statically linked by default and can thus be removed again after building LDC. It does not have to be installed system-wide.

LLVM 3.1

• There is an infinite recursion bug in the scalar evolution optimization pass in LLVM 3.1 (LLVM PR: TBD). It is known to be triggered by the std.exception unit tests on x86_64. In GDB, the cycle looks similar to this:

[…]
#2 llvm::ScalarEvolution::isKnownPredicate(llvm::CmpInst::Predicate, llvm::SCEV const*, llvm::SCEV const*) ()
#3 llvm::ScalarEvolution::getUMaxExpr(llvm::SmallVectorImpl<llvm::SCEV const*>&) ()
#4 llvm::ScalarEvolution::getUMaxExpr(llvm::SCEV const*, llvm::SCEV const*) ()
#5 llvm::ScalarEvolution::createSCEV(llvm::Value*) ()
#6 llvm::ScalarEvolution::getSCEV(llvm::Value*) ()
#7 llvm::ScalarEvolution::isImpliedCond(llvm::CmpInst::Predicate, llvm::SCEV const*, llvm::SCEV const*, llvm::Value*, bool) ()
#8 llvm::ScalarEvolution::isKnownPredicate(llvm::CmpInst::Predicate, llvm::SCEV const*, llvm::SCEV const*) ()
[…]

The issue does not occur on LLVM 3.0 and 3.2. Because of this, the release-mode std.exception unittests with reduced optimizations on x86_64 LLVM 3.1.