[ConstFold] Assertion failure folding llvm.vector.reduce on bitcast

[nikic]

Bugzilla Link	51811
Resolution	FIXED
Resolved on	Sep 10, 2021 09:27
Version	trunk
OS	Linux
Blocks	#50580
Fixed by commit(s)	af382b9 1ff9aa2

Extended Description

; RUN: opt -S -instsimplify < %s
define i8 @​test() {
%r = call i8 @​llvm.vector.reduce.mul.v16i8(<16 x i8> bitcast (<1 x i128> <i128 20011376718272490338853433276725592320> to <16 x i8>))
ret i8 %r
}

declare i8 @​llvm.vector.reduce.mul.v16i8(<16 x i8>)

opt: /home/nikic/llvm-project/llvm/include/llvm/Support/Casting.h:104: static bool llvm::isa_impl_cl<To, const From*>::doit(const From*) [with To = llvm::PoisonValue; From = llvm::Constant]: Assertion `Val && "isa<> used on a null pointer"' failed.
[...]
#​9 0x0000564c89438b9d llvm::Constant::containsPoisonElement() const (build/bin/opt+0x28bfb9d)
#​10 0x0000564c88b69eaa (anonymous namespace)::ConstantFoldScalarCall1(llvm::StringRef, unsigned int, llvm::Type*, llvm::ArrayRefllvm::Constant*, llvm::TargetLibraryInfo const*, llvm::CallBase const*) ConstantFolding.cpp:0:0

containsPoisonElement() does not account for the possibility of constant expressions, in which case getAggregateElement() may return null.

[nikic]

Fixed by af382b9.

[tstellar]

Merged: 1ff9aa2