From 1c043a9f28629929719c7262c74f837476416d43 Mon Sep 17 00:00:00 2001 From: Bjorn Pettersson Date: Tue, 24 Oct 2017 12:08:11 +0000 Subject: [ConstantFolding] Avoid assert when folding ptrtoint of vectorized GEP Summary: Got asserts in llvm::CastInst::getCastOpcode saying: `DestBits == SrcBits && "Illegal cast to vector (wrong type or size)"' failed. Problem seemed to be that llvm::ConstantFoldCastInstruction did not handle ptrtoint cast of a getelementptr returning a vector correctly. I assume such situations are quite rare, since the GEP needs to be considered as a constant value (base pointer being null). The solution used here is to simply avoid the constant fold of ptrtoint when the value is a vector. It is not supported, and by bailing out we do not fail on assertions later on. Reviewers: craig.topper, majnemer, davide, filcab, efriedma Reviewed By: efriedma Subscribers: efriedma, filcab, llvm-commits Differential Revision: https://reviews.llvm.org/D38546 llvm-svn: 316430 --- llvm/lib/IR/ConstantFold.cpp | 9 +++++++++ 1 file changed, 9 insertions(+) (limited to 'llvm/lib/IR/ConstantFold.cpp') diff --git a/llvm/lib/IR/ConstantFold.cpp b/llvm/lib/IR/ConstantFold.cpp index 60dd20e4659..044cc1ff449 100644 --- a/llvm/lib/IR/ConstantFold.cpp +++ b/llvm/lib/IR/ConstantFold.cpp @@ -629,6 +629,15 @@ Constant *llvm::ConstantFoldCastInstruction(unsigned opc, Constant *V, if (ConstantExpr *CE = dyn_cast(V)) if (CE->getOpcode() == Instruction::GetElementPtr && CE->getOperand(0)->isNullValue()) { + // FIXME: Looks like getFoldedSizeOf(), getFoldedOffsetOf() and + // getFoldedAlignOf() don't handle the case when DestTy is a vector of + // pointers yet. We end up in asserts in CastInst::getCastOpcode (see + // test/Analysis/ConstantFolding/cast-vector.ll). I've only seen this + // happen in one "real" C-code test case, so it does not seem to be an + // important optimization to handle vectors here. For now, simply bail + // out. + if (DestTy->isVectorTy()) + return nullptr; GEPOperator *GEPO = cast(CE); Type *Ty = GEPO->getSourceElementType(); if (CE->getNumOperands() == 2) { -- cgit v1.2.3