[PATCH] D51486: Add check to Latch's terminator in UnrollRuntimeLoopRemainder

[Dave Green via Phabricator via llvm-commits]

dmgreen added a comment.

Because I wanted to make sure it worked, I wrote this. Feel free to clean it up and use it as a unittest if you like:

  //===- BasicBlockUtils.cpp - Unit tests for BasicBlockUtils ---------------===//
  //
  //                     The LLVM Compiler Infrastructure
  //
  // This file is distributed under the University of Illinois Open Source
  // License. See LICENSE.TXT for details.
  //
  //===----------------------------------------------------------------------===//
  
  #include "llvm/Transforms/Utils/UnrollLoop.h"
  #include "llvm/Analysis/AssumptionCache.h"
  #include "llvm/Analysis/LoopInfo.h"
  #include "llvm/Analysis/ScalarEvolution.h"
  #include "llvm/Analysis/TargetLibraryInfo.h"
  #include "llvm/AsmParser/Parser.h"
  #include "llvm/IR/BasicBlock.h"
  #include "llvm/IR/Dominators.h"
  #include "llvm/IR/LLVMContext.h"
  #include "llvm/Support/SourceMgr.h"
  #include "gtest/gtest.h"
  
  using namespace llvm;
  
  static std::unique_ptr<Module> parseIR(LLVMContext &C, const char *IR) {
    SMDiagnostic Err;
    std::unique_ptr<Module> Mod = parseAssemblyString(IR, Err, C);
    if (!Mod)
      Err.print("BasicBlockUtilsTests", errs());
    return Mod;
  }
  
  TEST(LoopUnrollRuntime, Latch) {
    LLVMContext C;
  
    std::unique_ptr<Module> M = parseIR(
      C,
      R"(define i32 @test(i32* %a, i32* %b, i32* %c, i64 %n) {
  entry:
    br label %while.cond
  
  while.cond:                                       ; preds = %while.body, %entry
    %i.0 = phi i64 [ 0, %entry ], [ %inc, %while.body ]
    %cmp = icmp slt i64 %i.0, %n
    br i1 %cmp, label %while.body, label %while.end
  
  while.body:                                       ; preds = %while.cond
    %arrayidx = getelementptr inbounds i32, i32* %b, i64 %i.0
    %0 = load i32, i32* %arrayidx
    %arrayidx1 = getelementptr inbounds i32, i32* %c, i64 %i.0
    %1 = load i32, i32* %arrayidx1
    %mul = mul nsw i32 %0, %1
    %arrayidx2 = getelementptr inbounds i32, i32* %a, i64 %i.0
    store i32 %mul, i32* %arrayidx2
    %inc = add nsw i64 %i.0, 1
    br label %while.cond
  
  while.end:                                        ; preds = %while.cond
    ret i32 0
  })"
      );
  
    auto *F = M->getFunction("test");
    DominatorTree DT(*F);
    LoopInfo LI(DT);
    AssumptionCache AC(*F);
    TargetLibraryInfoImpl TLII;
    TargetLibraryInfo TLI(TLII);
    ScalarEvolution SE(*F, TLI, AC, DT, LI);
  
    bool ret = UnrollRuntimeLoopRemainder(*LI.begin(), 4, true, true, false, &LI, &SE, &DT, &AC, true);
    EXPECT_FALSE(ret);
  }


Repository:
  rL LLVM

https://reviews.llvm.org/D51486