Assertion failure in TargetLoweringBase::isFAbsFree during SLP vectorization

[llvmbot]

Bugzilla Link	36628
Version	trunk
OS	Linux
Attachments	Backtrace, Reduced test case
Reporter	LLVM Bugzilla Contributor
CC	@sunfishcode,@sbc100

Extended Description

The failing program is musl's multc3 when compiled for wasm32. I will attach a reduced test case in the next comment.

[llvmbot]

Sorry, I meant compiler-rt, not musl.

[sunfishcode]

The testcase works for me with current trunk, processing it with opt -S -slp-vectorizer. Can you say what revision level of LLVM you see this with?

[llvmbot]

I'm still getting the same error on the same file with commit 9c07603 (revision 330542):

$ opt -mtriple=wasm32-unknown-unknown reduced.ll -S -slp-vectorizer
opt: llvm/include/llvm/CodeGen/TargetLowering.h:2191: virtual bool llvm::TargetLoweringBase::isFAbsFree(llvm::EVT) const: Assertion `VT.isFloatingPoint()' failed.

Are you building LLVM with the WebAssembly backend enabled?

[sunfishcode]

I'm able to reproduce it now. It seems to be a bug in target-independent code, as I'm also able to reproduce it with -mtriple=x86_64-unknown-unknown rather than wasm32.

The problem is related to the f128 fabs, which legalizes to two i64s, which the generic isFAbsFree function doesn't know how to handle, because i64 isn't floating-point.

[sbc100]

Did this ever get fixed?

[alexey-bataev]

Does not reproduce currently, fixed