Move O0 logic to front of codegen, minor test and code fixups

Author: SLTozer

clang/lib/CodeGen/CGCleanup.cpp

@@ -116,7 +116,11 @@ bool EHScopeStack::containsOnlyNoopCleanups(
     EHScopeStack::stable_iterator Old) const {
   for (EHScopeStack::iterator it = begin(); stabilize(it) != Old; it++) {
     EHCleanupScope *cleanup = dyn_cast<EHCleanupScope>(&*it);
-    if (!cleanup || !(cleanup->isLifetimeMarker() || cleanup->isFakeUse()))
+    // If this is anything other than a lifetime marker or fake use cleanup,
+    // then the scope stack does not contain only noop cleanups.
+    if (!cleanup)
+      return false;
+    if (!cleanup->isLifetimeMarker() && !cleanup->isFakeUse())
       return false;
   }
 

clang/lib/CodeGen/CGDecl.cpp

@@ -1717,7 +1717,7 @@ CodeGenFunction::EmitAutoVarAlloca(const VarDecl &D) {
   if (CGM.getCodeGenOpts().ExtendLifetimes) {
     if (extendLifetime(getContext(), CurCodeDecl, D, CXXABIThisDecl))
       EHStack.pushCleanup<FakeUse>(NormalFakeUse,
-                                   emission.getAllocatedAddress());
+                                   emission.getOriginalAllocatedAddress());
   }
 
   return emission;

clang/lib/Frontend/CompilerInvocation.cpp

@@ -1834,6 +1834,13 @@ bool CompilerInvocation::ParseCodeGenArgs(CodeGenOptions &Opts, ArgList &Args,
     Opts.setInlining(CodeGenOptions::NormalInlining);
   }
 
+  // Extended lifetimes are meaningless if we are not going to run any
+  // optimizations, so skip them here.
+  if (Opts.OptimizationLevel == 0 && !Opts.DisableO0ImplyOptNone) {
+    Opts.ExtendLifetimes = false;
+    Opts.ExtendThisPtr = false;
+  }
+
   // PIC defaults to -fno-direct-access-external-data while non-PIC defaults to
   // -fdirect-access-external-data.
   Opts.DirectAccessExternalData =

clang/test/CodeGen/fake-use-landingpad.c

@@ -1,4 +1,4 @@
-// RUN: %clang_cc1 %s -O0 -disable-O0-optnone -emit-llvm -fextend-lifetimes -fexceptions -o - | FileCheck %s --implicit-check-not=landingpad
+// RUN: %clang_cc1 %s -O0 -disable-O0-optnone -emit-llvm -fextend-lifetimes -fexceptions -o - | FileCheck %s --implicit-check-not="landingpad {"
 
 // Check that fake uses do not mistakenly cause a landing pad to be generated when
 // exceptions are enabled.