[all-commits] [llvm/llvm-project] 86bf23: [IR] Change the default value of InstertElement to...

[Hyeongyu Kim via All-commits]

  Branch: refs/heads/main
  Home:   https://github.com/llvm/llvm-project
  Commit: 86bf234d0b7038479292a0d771dc05966140b908
      https://github.com/llvm/llvm-project/commit/86bf234d0b7038479292a0d771dc05966140b908
  Author: hyeongyu kim <gusrb406 at snu.ac.kr>
  Date:   2021-09-28 (Tue, 28 Sep 2021)

  Changed paths:
    M llvm/include/llvm/IR/IRBuilder.h
    M llvm/lib/IR/AutoUpgrade.cpp
    M llvm/lib/Target/NVPTX/NVPTXGenericToNVVM.cpp
    M llvm/unittests/IR/IRBuilderTest.cpp
    M llvm/unittests/IR/PatternMatch.cpp

  Log Message:
  -----------
  [IR] Change the default value of InstertElement to poison (1/4)

This patch is for fixing potential insertElement-related bugs like D93818.
```
V = UndefValue::get(VecTy);
for(...)
  V = Builder.CreateInsertElementy(V, Elt, Idx);
=>
V = PoisonValue::get(VecTy);
for(...)
  V = Builder.CreateInsertElementy(V, Elt, Idx);
```
Like above, this patch changes the placeholder V to poison.
The patch will be separated into several commits.

Reviewed By: aqjune

Differential Revision: https://reviews.llvm.org/D110311