[PATCH] D30703: [DSE] Merge stores when the later store only writes to memory locations the early store also wrote to.

Fri Aug 4 13:15:44 PDT 2017

rnk added a comment.

We're seeing null derefs on some code in Chromium after this patch:

  ninja -v -d keeprsp -C out\clang_tot obj/third_party/angle/libANGLE/Caps.obj
  ninja.exe -v -d keeprsp -C out\clang_tot obj/third_party/angle/libANGLE/Caps.obj -j 46 -l 48
  ninja: Entering directory `out\clang_tot'
  [1 processes, 1/1 @ 0.2/s : 4.732s ] ../../third_party/llvm-build/Release+Asserts/bin/clang-cl.exe /nologo /showIncludes  @obj/third_party/angle/libANGLE/Caps.obj.rsp /c ../../third_party/angle/src/libANGLE/Caps.cpp /Foobj/third_party/angle/libANGLE/Caps.obj /Fd"obj/third_party/angle/libANGLE_cc.pdb"
  FAILED: obj/third_party/angle/libANGLE/Caps.obj
  ../../third_party/llvm-build/Release+Asserts/bin/clang-cl.exe /nologo /showIncludes  @obj/third_party/angle/libANGLE/Caps.obj.rsp /c ../../third_party/angle/src/libANGLE/Caps.cpp /Foobj/third_party/angle/libANGLE/Caps.obj /Fd"obj/third_party/angle/libANGLE_cc.pdb"
  Assertion failed: Val && "isa<> used on a null pointer", file C:\src\chromium3\src\third_party\llvm\include\llvm/Support/Casting.h, line 106
  Wrote crash dump file "c:\src\Temp\clang-cl.exe-d4113f.dmp"
  #0 0x00007ff6f6338775 HandleAbort c:\src\chromium3\src\third_party\llvm\lib\support\windows\signals.inc:411:0
  #1 0x00007ff6f7b99769 raise minkernel\crts\ucrt\src\appcrt\misc\signal.cpp:516:0
  #2 0x00007ff6f7b86df8 abort minkernel\crts\ucrt\src\appcrt\startup\abort.cpp:71:0
  #3 0x00007ff6f7b86532 common_assert_to_stderr<wchar_t> minkernel\crts\ucrt\src\appcrt\startup\assert.cpp:149:0
  #4 0x00007ff6f7b865ce _wassert minkernel\crts\ucrt\src\appcrt\startup\assert.cpp:404:0
  #5 0x00007ff6f5ed6de3 llvm::GEPOperator::hasAllZeroIndices(void)const  c:\src\chromium3\src\third_party\llvm\include\llvm\ir\operator.h:456:0
  #6 0x00007ff6f5ed32fe `anonymous namespace'::stripPointerCastsAndOffsets<1> c:\src\chromium3\src\third_party\llvm\lib\ir\value.cpp:483:0
  #7 0x00007ff6f61bd100 isOverwrite c:\src\chromium3\src\third_party\llvm\lib\transforms\scalar\deadstoreelimination.cpp:326:0
  #8 0x00007ff6f61b9bd6 eliminateDeadStores c:\src\chromium3\src\third_party\llvm\lib\transforms\scalar\deadstoreelimination.cpp:1131:0
  #9 0x00007ff6f61ba7d7 eliminateDeadStores c:\src\chromium3\src\third_party\llvm\lib\transforms\scalar\deadstoreelimination.cpp:1265:0
  #10 0x00007ff6f61bf55c `anonymous namespace'::DSELegacyPass::runOnFunction c:\src\chromium3\src\third_party\llvm\lib\transforms\scalar\deadstoreelimination.cpp:1308:0
  #11 0x00007ff6f5ee35fd llvm::FPPassManager::runOnFunction(class llvm::Function &) c:\src\chromium3\src\third_party\llvm\lib\ir\legacypassmanager.cpp:1514:0
  #12 0x00007ff6f5bdae07 `anonymous namespace'::CGPassManager::RunPassOnSCC c:\src\chromium3\src\third_party\llvm\lib\analysis\callgraphsccpass.cpp:149:0
  #13 0x00007ff6f5bdab93 `anonymous namespace'::CGPassManager::RunAllPassesOnSCC c:\src\chromium3\src\third_party\llvm\lib\analysis\callgraphsccpass.cpp:418:0
  #14 0x00007ff6f5bdba59 `anonymous namespace'::CGPassManager::runOnModule c:\src\chromium3\src\third_party\llvm\lib\analysis\callgraphsccpass.cpp:474:0
  #15 0x00007ff6f5ee3a3e `anonymous namespace'::MPPassManager::runOnModule c:\src\chromium3\src\third_party\llvm\lib\ir\legacypassmanager.cpp:1591:0
  #16 0x00007ff6f5ee2ef1 llvm::legacy::PassManagerImpl::run(class llvm::Module &) c:\src\chromium3\src\third_party\llvm\lib\ir\legacypassmanager.cpp:1695:0
  #17 0x00007ff6f653810c `anonymous namespace'::EmitAssemblyHelper::EmitAssembly c:\src\chromium3\src\third_party\llvm\tools\clang\lib\codegen\backendutil.cpp:788:0
  #18 0x00007ff6f653a140 clang::EmitBackendOutput(class clang::DiagnosticsEngine &,class clang::HeaderSearchOptions const &,class clang::CodeGenOptions const &,class clang::TargetOptions const &,class clang::LangOptions const &,class llvm::DataLayout const &,class llvm::Module *,enum clang::BackendAction,class std::unique_ptr<class llvm::raw_pwrite_stream,struct std::default_delete<class llvm::raw_pwrite_stream> >) c:\src\chromium3\src\third_party\llvm\tools\clang\lib\codegen\backendutil.cpp:1148:0
  #19 0x00007ff6f7cc3a31 clang::BackendConsumer::HandleTranslationUnit(class clang::ASTContext &) c:\src\chromium3\src\third_party\llvm\tools\clang\lib\codegen\codegenaction.cpp:265:0
  #20 0x00007ff6f68c6cbc clang::MultiplexConsumer::HandleTranslationUnit(class clang::ASTContext &) c:\src\chromium3\src\third_party\llvm\tools\clang\lib\frontend\multiplexconsumer.cpp:305:0
  #21 0x00007ff6f6f224d6 clang::ParseAST(class clang::Sema &,bool,bool) c:\src\chromium3\src\third_party\llvm\tools\clang\lib\parse\parseast.cpp:162:0
  #22 0x00007ff6f688654d clang::ASTFrontendAction::ExecuteAction(void) c:\src\chromium3\src\third_party\llvm\tools\clang\lib\frontend\frontendaction.cpp:1005:0
  #23 0x00007ff6f7cc30fb clang::CodeGenAction::ExecuteAction(void) c:\src\chromium3\src\third_party\llvm\tools\clang\lib\codegen\codegenaction.cpp:992:0
  #24 0x00007ff6f68863db clang::FrontendAction::Execute(void) c:\src\chromium3\src\third_party\llvm\tools\clang\lib\frontend\frontendaction.cpp:906:0
  #25 0x00007ff6f6873b65 clang::CompilerInstance::ExecuteAction(class clang::FrontendAction &) c:\src\chromium3\src\third_party\llvm\tools\clang\lib\frontend\compilerinstance.cpp:981:0
  #26 0x00007ff6f68f7bfd clang::ExecuteCompilerInvocation(class clang::CompilerInstance *) c:\src\chromium3\src\third_party\llvm\tools\clang\lib\frontendtool\executecompilerinvocation.cpp:252:0
  #27 0x00007ff6f4fc5ff4 cc1_main(class llvm::ArrayRef<char const *>,char const *,void *) c:\src\chromium3\src\third_party\llvm\tools\clang\tools\driver\cc1_main.cpp:221:0
  #28 0x00007ff6f4fc1d40 ExecuteCC1Tool c:\src\chromium3\src\third_party\llvm\tools\clang\tools\driver\driver.cpp:313:0
  #29 0x00007ff6f4fc3b3a main c:\src\chromium3\src\third_party\llvm\tools\clang\tools\driver\driver.cpp:387:0
  #30 0x00007ff6f7b6349d __scrt_common_main_seh f:\dd\vctools\crt\vcstartup\src\startup\exe_common.inl:283:0
  #31 0x00007ff855298364 (C:\WINDOWS\System32\KERNEL32.DLL+0x8364)
  #32 0x00007ff855e870d1 (C:\WINDOWS\SYSTEM32\ntdll.dll+0x670d1)
  clang-cl.exe: error: clang frontend command failed due to signal (use -v to see invocation

I'll try to get a repro, but heads up.

Repository:
  rL LLVM

https://reviews.llvm.org/D30703