Possible NULL dereference in llvm/Transforms/Scalar

[apach301]

Hi,

I found possible null pointer dereference with Svace static analyzer.

A SIUse pointer is checked on NULL and then dereferenced while casting in isValidSelectInst() at llvm/lib/Transforms/Scalar/DFAJumpThreading.cpp:

llvm-project/llvm/lib/Transforms/Scalar/DFAJumpThreading.cpp

Lines 522 to 525 in b5a1747

	Instruction *SIUse = dyn_cast<Instruction>(SI->user_back());
	// The use of the select inst should be either a phi or another select.
	if (!SIUse && !(isa<PHINode>(SIUse) || isa<SelectInst>(SIUse)))
	return false;