[llvm-dev] Intrinsic opt failure

Konstantin Vladimirov via llvm-dev llvm-dev at lists.llvm.org
Tue Feb 16 06:44:37 PST 2016


Working on private backend, based on llvm-3.7

Inside lib/Transforms/InstCombine/InstCombineCompares.cpp there is
attempt to optimize fabs:

        if (F->getIntrinsicID() == Intrinsic::fabs ||
          switch (I.getPredicate()) {
          case FCmpInst::FCMP_OGT:
            return new FCmpInst(FCmpInst::FCMP_ONE, CI->getArgOperand(0), RHSC);


CI->getArgOperand(0) returns operand with type (double*) rather then
double, because in our ABI doubles are passed via memory.

Next assertion fires inside FCmpInst ctor:

llvm::FCmpInst::FCmpInst(llvm::CmpInst::Predicate, llvm::Value*,
llvm::Value*, const llvm::Twine&): Assertion `getOperand(0)->getType()
== getOperand(1)->getType() && "Both operands to FCmp instruction are
not of the same type!"' failed.

I think, here required some check that CI->getArgOperand returns
correct value before trying to optimize.

What would you advise?

With best regards, Konstantin

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