AMDGPU: Fix incorrect selection of pseudo-branches

These should only be used if the machine structurizer is enabled.

llvm-svn: 315357

llvm/lib/Target/AMDGPU/AMDGPU.td

@@ -724,6 +724,8 @@ def HasIntClamp : Predicate<"Subtarget->hasIntClamp()">,
 def HasMadMix : Predicate<"Subtarget->hasMadMixInsts()">,
   AssemblerPredicate<"FeatureGFX9Insts">;
 
+def EnableLateCFGStructurize : Predicate<
+  "EnableLateStructurizeCFG">;
 
 // Exists to help track down where SubtargetPredicate isn't set rather
 // than letting tablegen crash with an unhelpful error.

llvm/lib/Target/AMDGPU/AMDGPUISelDAGToDAG.cpp

@@ -18,6 +18,7 @@
 #include "AMDGPUInstrInfo.h"
 #include "AMDGPURegisterInfo.h"
 #include "AMDGPUSubtarget.h"
+#include "AMDGPUTargetMachine.h"
 #include "SIDefines.h"
 #include "SIISelLowering.h"
 #include "SIInstrInfo.h"
@@ -69,12 +70,14 @@ class AMDGPUDAGToDAGISel : public SelectionDAGISel {
   // make the right decision when generating code for different targets.
   const AMDGPUSubtarget *Subtarget;
   AMDGPUAS AMDGPUASI;
+  bool EnableLateStructurizeCFG;
 
 public:
   explicit AMDGPUDAGToDAGISel(TargetMachine *TM = nullptr,
                               CodeGenOpt::Level OptLevel = CodeGenOpt::Default)
     : SelectionDAGISel(*TM, OptLevel) {
     AMDGPUASI = AMDGPU::getAMDGPUAS(*TM);
+    EnableLateStructurizeCFG = AMDGPUTargetMachine::EnableLateStructurizeCFG;
   }
   ~AMDGPUDAGToDAGISel() override = default;
 

llvm/lib/Target/AMDGPU/AMDGPUTargetMachine.cpp

@@ -117,10 +117,10 @@ static cl::opt<bool> EnableSIInsertWaitcntsPass(
   cl::init(true));
 
 // Option to run late CFG structurizer
-static cl::opt<bool> LateCFGStructurize(
+static cl::opt<bool, true> LateCFGStructurize(
   "amdgpu-late-structurize",
   cl::desc("Enable late CFG structurization"),
-  cl::init(false),
+  cl::location(AMDGPUTargetMachine::EnableLateStructurizeCFG),
   cl::Hidden);
 
 static cl::opt<bool> EnableAMDGPUFunctionCalls(
@@ -300,6 +300,8 @@ AMDGPUTargetMachine::AMDGPUTargetMachine(const Target &T, const Triple &TT,
 
 AMDGPUTargetMachine::~AMDGPUTargetMachine() = default;
 
+bool AMDGPUTargetMachine::EnableLateStructurizeCFG = false;
+
 StringRef AMDGPUTargetMachine::getGPUName(const Function &F) const {
   Attribute GPUAttr = F.getFnAttribute("target-cpu");
   return GPUAttr.hasAttribute(Attribute::None) ?

llvm/lib/Target/AMDGPU/AMDGPUTargetMachine.h

@@ -41,6 +41,8 @@ protected:
   StringRef getFeatureString(const Function &F) const;
 
 public:
+  static bool EnableLateStructurizeCFG;
+
   AMDGPUTargetMachine(const Target &T, const Triple &TT, StringRef CPU,
                       StringRef FS, TargetOptions Options,
                       Optional<Reloc::Model> RM, Optional<CodeModel::Model> CM,

llvm/lib/Target/AMDGPU/SIInstructions.td

@@ -204,12 +204,14 @@ def SI_MASK_BRANCH : VPseudoInstSI <
 
 let isTerminator = 1 in {
 
+let OtherPredicates = [EnableLateCFGStructurize] in {
  def SI_NON_UNIFORM_BRCOND_PSEUDO : CFPseudoInstSI <
   (outs),
   (ins SReg_64:$vcc, brtarget:$target),
   [(brcond i1:$vcc, bb:$target)]> {
     let Size = 12;
 }
+}
 
 def SI_IF: CFPseudoInstSI <
   (outs SReg_64:$dst), (ins SReg_64:$vcc, brtarget:$target),