Make sure -optimize-regalloc=false is used correctly by user.

Don't allow -optimize-regalloc=false with -regalloc given for anything other
than 'fast'. The other register allocators depend on the supporting passes
added by addOptimizedRegAlloc().

Reviewers: Quentin Colombet, Matthias Braun
https://reviews.llvm.org/D33181

llvm-svn: 303238

lib/CodeGen/TargetPassConfig.cpp

@@ -564,6 +564,14 @@ void TargetPassConfig::addISelPrepare() {
     addPass(createVerifierPass());
 }
 
+/// -regalloc=... command line option.
+static FunctionPass *useDefaultRegisterAllocator() { return nullptr; }
+static cl::opt<RegisterRegAlloc::FunctionPassCtor, false,
+               RegisterPassParser<RegisterRegAlloc> >
+RegAlloc("regalloc",
+         cl::init(&useDefaultRegisterAllocator),
+         cl::desc("Register allocator to use"));
+
 /// Add the complete set of target-independent postISel code generator passes.
 ///
 /// This can be read as the standard order of major LLVM CodeGen stages. Stages
@@ -625,8 +633,12 @@ void TargetPassConfig::addMachinePasses() {
   // including phi elimination and scheduling.
   if (getOptimizeRegAlloc())
     addOptimizedRegAlloc(createRegAllocPass(true));
-  else
+  else {
+    if (RegAlloc != &useDefaultRegisterAllocator &&
+        RegAlloc != &createFastRegisterAllocator)
+      report_fatal_error("Must use fast (default) register allocator for unoptimized regalloc.");
     addFastRegAlloc(createRegAllocPass(false));
+  }
 
   // Run post-ra passes.
   addPostRegAlloc();
@@ -759,19 +771,12 @@ MachinePassRegistry RegisterRegAlloc::Registry;
 /// A dummy default pass factory indicates whether the register allocator is
 /// overridden on the command line.
 static llvm::once_flag InitializeDefaultRegisterAllocatorFlag;
-static FunctionPass *useDefaultRegisterAllocator() { return nullptr; }
+
 static RegisterRegAlloc
 defaultRegAlloc("default",
                 "pick register allocator based on -O option",
                 useDefaultRegisterAllocator);
 
-/// -regalloc=... command line option.
-static cl::opt<RegisterRegAlloc::FunctionPassCtor, false,
-               RegisterPassParser<RegisterRegAlloc> >
-RegAlloc("regalloc",
-         cl::init(&useDefaultRegisterAllocator),
-         cl::desc("Register allocator to use"));
-
 static void initializeDefaultRegisterAllocatorOnce() {
   RegisterRegAlloc::FunctionPassCtor Ctor = RegisterRegAlloc::getDefault();
 
@@ -781,7 +786,6 @@ static void initializeDefaultRegisterAllocatorOnce() {
   }
 }
 
-
 /// Instantiate the default register allocator pass for this target for either
 /// the optimized or unoptimized allocation path. This will be added to the pass
 /// manager by addFastRegAlloc in the unoptimized case or addOptimizedRegAlloc