[all-commits] [llvm/llvm-project] 0581c0: Revert "[SCEV] Look through single value PHIs."

[alitamur via All-commits]

  Branch: refs/heads/master
  Home:   https://github.com/llvm/llvm-project
  Commit: 0581c0b0eeba03da590d1176a4580cf9b9e8d1e3
      https://github.com/llvm/llvm-project/commit/0581c0b0eeba03da590d1176a4580cf9b9e8d1e3
  Author: Ali Tamur <tamur at google.com>
  Date:   2020-08-12 (Wed, 12 Aug 2020)

  Changed paths:
    M llvm/lib/Analysis/ScalarEvolution.cpp
    M llvm/test/Analysis/ScalarEvolution/solve-quadratic-i1.ll
    M llvm/test/Analysis/ScalarEvolution/solve-quadratic-overflow.ll
    M llvm/test/Transforms/LoopStrengthReduce/funclet.ll

  Log Message:
  -----------
  Revert "[SCEV] Look through single value PHIs."

This reverts commit e441b7a7a0a72c28daf5a8e594559c667e5b4534.

This patch causes a compile error in tensorflow opensource project. The stack trace looks like:

Point of crash:
llvm/include/llvm/Analysis/LoopInfoImpl.h : line 35

(gdb) ptype *this
type = const class llvm::LoopBase<llvm::BasicBlock, llvm::Loop> [with BlockT = llvm::BasicBlock, LoopT = llvm::Loop]

(gdb) p *this
$1 = {ParentLoop = 0x0, SubLoops = std::vector of length 0, capacity 0, Blocks = std::vector of length 0, capacity 1,
  DenseBlockSet = {<llvm::SmallPtrSetImpl<llvm::BasicBlock const*>> = {<llvm::SmallPtrSetImplBase> = {<llvm::DebugEpochBase> = {Epoch = 3}, SmallArray = 0x1b2bf6c8, CurArray = 0x1b2bf6c8,
        CurArraySize = 8, NumNonEmpty = 0, NumTombstones = 0}, <No data fields>}, SmallStorage = {0xfffffffffffffffe, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0}}, IsInvalid = true}

(gdb) p *this->DenseBlockSet->CurArray
$2 = (const void *) 0xfffffffffffffffe

I will try to get a case from tensorflow or use creduce to get a small case.