68#define DEBUG_TYPE "amdgpu-rewrite-undef-for-phi"
72class AMDGPURewriteUndefForPHILegacy :
public FunctionPass {
80 return "AMDGPU Rewrite Undef for PHI";
94char AMDGPURewriteUndefForPHILegacy::ID = 0;
97 "Rewrite undef for PHI",
false,
false)
104 bool Changed =
false;
107 for (
auto &
PHI : BB.phis()) {
108 if (UA.isDivergent(&
PHI))
112 Value *UniqueDefinedIncoming =
nullptr;
119 for (
unsigned i = 0; i <
PHI.getNumIncomingValues(); i++) {
120 Value *Incoming =
PHI.getIncomingValue(i);
123 if (Incoming == &
PHI)
126 if (isa<UndefValue>(Incoming)) {
128 if (!DT->dominates(&BB, IncomingBB))
133 if (!UniqueDefinedIncoming) {
134 UniqueDefinedIncoming = Incoming;
135 DominateBB = IncomingBB;
136 }
else if (Incoming == UniqueDefinedIncoming) {
138 if (DT->dominates(IncomingBB, DominateBB))
139 DominateBB = IncomingBB;
141 UniqueDefinedIncoming =
nullptr;
149 if (!UniqueDefinedIncoming || Undefs.
empty() ||
158 return DT->dominates(DominateBB, UD);
160 PHI.replaceAllUsesWith(UniqueDefinedIncoming);
167 for (
auto *
PHI : ToBeDeleted)
168 PHI->eraseFromParent();
173bool AMDGPURewriteUndefForPHILegacy::runOnFunction(
Function &
F) {
175 getAnalysis<UniformityInfoWrapperPass>().getUniformityInfo();
176 DominatorTree *DT = &getAnalysis<DominatorTreeWrapperPass>().getDomTree();
195 return new AMDGPURewriteUndefForPHILegacy();
for(const MachineOperand &MO :llvm::drop_begin(OldMI.operands(), Desc.getNumOperands()))
Rewrite undef for false bool rewritePHIs(Function &F, UniformityInfo &UA, DominatorTree *DT)
This file contains the declarations for the subclasses of Constant, which represent the different fla...
#define INITIALIZE_PASS_DEPENDENCY(depName)
#define INITIALIZE_PASS_END(passName, arg, name, cfg, analysis)
#define INITIALIZE_PASS_BEGIN(passName, arg, name, cfg, analysis)
PreservedAnalyses run(Function &F, FunctionAnalysisManager &AM)
A container for analyses that lazily runs them and caches their results.
PassT::Result & getResult(IRUnitT &IR, ExtraArgTs... ExtraArgs)
Get the result of an analysis pass for a given IR unit.
Represent the analysis usage information of a pass.
AnalysisUsage & addRequired()
AnalysisUsage & addPreserved()
Add the specified Pass class to the set of analyses preserved by this pass.
void setPreservesCFG()
This function should be called by the pass, iff they do not:
LLVM Basic Block Representation.
const Instruction * getTerminator() const LLVM_READONLY
Returns the terminator instruction if the block is well formed or null if the block is not well forme...
Represents analyses that only rely on functions' control flow.
Analysis pass which computes a DominatorTree.
Legacy analysis pass which computes a DominatorTree.
Concrete subclass of DominatorTreeBase that is used to compute a normal dominator tree.
FunctionPass class - This class is used to implement most global optimizations.
virtual bool runOnFunction(Function &F)=0
runOnFunction - Virtual method overriden by subclasses to do the per-function processing of the pass.
static PassRegistry * getPassRegistry()
getPassRegistry - Access the global registry object, which is automatically initialized at applicatio...
virtual void getAnalysisUsage(AnalysisUsage &) const
getAnalysisUsage - This function should be overriden by passes that need analysis information to do t...
virtual StringRef getPassName() const
getPassName - Return a nice clean name for a pass.
A set of analyses that are preserved following a run of a transformation pass.
static PreservedAnalyses all()
Construct a special preserved set that preserves all passes.
void preserveSet()
Mark an analysis set as preserved.
void push_back(const T &Elt)
This is a 'vector' (really, a variable-sized array), optimized for the case when the array is small.
StringRef - Represent a constant reference to a string, i.e.
LLVM Value Representation.
unsigned ID
LLVM IR allows to use arbitrary numbers as calling convention identifiers.
This is an optimization pass for GlobalISel generic memory operations.
bool all_of(R &&range, UnaryPredicate P)
Provide wrappers to std::all_of which take ranges instead of having to pass begin/end explicitly.
void initializeAMDGPURewriteUndefForPHILegacyPass(PassRegistry &)
FunctionPass * createAMDGPURewriteUndefForPHILegacyPass()