llvm/llvm-project

Unnecessary vector type produces wrong ll parser error

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#29,043 opened on Jul 22, 2016

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bugzillagood first issuellvm:core

Description
Bugzilla Link 28669
Version trunk
OS Linux
CC @ekatz

Extended Description

This testcase produces a misleading parse error

; RUN: llvm-as < %s
define void @add_v2i16(<2 x i16> addrspace(1)* %out, <2 x i16> %in) {
  %arst = add <2 x i16> %in, <2 x i16> <i16 123, i16 456>
  store <2 x i16> %arst, <2 x i16> addrspace(1)* %out
  ret void
}

expected-type-wrong-error.ll:3:31: error: expected type
  %arst = add <2 x i16> %in, <2 x i16> <i16 123, i16 456>

It is erroring on the 2nd operand <2 x i16> type, it really means the type is unexpected. The correctly parsing version is

  %arst = add <2 x i16> %in, <i16 123, i16 456>

Contributor guide

Tech stack
cpp
Domain
toolingcli
Issue type
bug
DifficultyEstimated implementation difficulty for a new contributor, from 1 for very small changes to 5 for expert-level work.
3
Estimated timeA rough time range for an experienced contributor to investigate, implement, test, and prepare a pull request.
1-3 hours
Activity statusHow available the issue appears right now: fresh, active, stale, blocked, or waiting on maintainer input.
stale
ClarityHow clearly the issue explains the expected change, acceptance criteria, and next step.
clear
Prerequisites
basic knowledge of LLVM IRC++ programming
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
30
Research direction
Investigate the LLVM assembler parser in llvm/lib/AsmParser/LLParser.cpp. Look for where the error message 'expected type' is generated when parsing the second operand of an add instruction. The issue indicates that the parser incorrectly rejects a redundant type specifier. Determine if the fix should improve the error message or allow the redundant type as valid syntax. Check comments in the issue and consider any linked PRs.