[AMDGPU] gfx1010 wavefrontsize intrinsic folding

Differential Revision: https://reviews.llvm.org/D63206

llvm-svn: 363588

3 files changed, 59 insertions, 16 deletions

diff --git a/llvm/lib/Target/AMDGPU/AMDGPU.h b/llvm/lib/Target/AMDGPU/AMDGPU.h
index 94dad0d7470..19a7b38004c 100644
--- a/llvm/lib/Target/AMDGPU/AMDGPU.h
+++ b/llvm/lib/Target/AMDGPU/AMDGPU.h
@@ -53,7 +53,8 @@ FunctionPass *createSIMemoryLegalizerPass();
 FunctionPass *createSIInsertWaitcntsPass();
 FunctionPass *createSIPreAllocateWWMRegsPass();
 FunctionPass *createSIFormMemoryClausesPass();
-FunctionPass *createAMDGPUSimplifyLibCallsPass(const TargetOptions &);
+FunctionPass *createAMDGPUSimplifyLibCallsPass(const TargetOptions &,
+                                               const TargetMachine *);
 FunctionPass *createAMDGPUUseNativeCallsPass();
 FunctionPass *createAMDGPUCodeGenPreparePass();
 FunctionPass *createAMDGPUMachineCFGStructurizerPass();
diff --git a/llvm/lib/Target/AMDGPU/AMDGPULibCalls.cpp b/llvm/lib/Target/AMDGPU/AMDGPULibCalls.cpp
index 581e229b4a0..7156824638a 100644
--- a/llvm/lib/Target/AMDGPU/AMDGPULibCalls.cpp
+++ b/llvm/lib/Target/AMDGPU/AMDGPULibCalls.cpp
@@ -15,6 +15,7 @@
 
 #include "AMDGPU.h"
 #include "AMDGPULibFunc.h"
+#include "AMDGPUSubtarget.h"
 #include "llvm/Analysis/AliasAnalysis.h"
 #include "llvm/Analysis/Loads.h"
 #include "llvm/ADT/StringSet.h"
@@ -22,6 +23,7 @@
 #include "llvm/IR/Constants.h"
 #include "llvm/IR/DerivedTypes.h"
 #include "llvm/IR/Instructions.h"
+#include "llvm/IR/Intrinsics.h"
 #include "llvm/IR/IRBuilder.h"
 #include "llvm/IR/Function.h"
 #include "llvm/IR/LLVMContext.h"
@@ -29,6 +31,7 @@
 #include "llvm/IR/ValueSymbolTable.h"
 #include "llvm/Support/Debug.h"
 #include "llvm/Support/raw_ostream.h"
+#include "llvm/Target/TargetMachine.h"
 #include "llvm/Target/TargetOptions.h"
 #include <vector>
 #include <cmath>
@@ -65,6 +68,8 @@ private:
 
   typedef llvm::AMDGPULibFunc FuncInfo;
 
+  const TargetMachine *TM;
+
   // -fuse-native.
   bool AllNative = false;
 
@@ -134,6 +139,9 @@ private:
   // __read_pipe/__write_pipe
   bool fold_read_write_pipe(CallInst *CI, IRBuilder<> &B, FuncInfo &FInfo);
 
+  // llvm.amdgcn.wavefrontsize
+  bool fold_wavefrontsize(CallInst *CI, IRBuilder<> &B);
+
   // Get insertion point at entry.
   BasicBlock::iterator getEntryIns(CallInst * UI);
   // Insert an Alloc instruction.
@@ -152,6 +160,8 @@ protected:
   }
 
 public:
+  AMDGPULibCalls(const TargetMachine *TM_ = nullptr) : TM(TM_) {}
+
   bool fold(CallInst *CI, AliasAnalysis *AA = nullptr);
 
   void initNativeFuncs();
@@ -166,15 +176,16 @@ namespace {
 
   class AMDGPUSimplifyLibCalls : public FunctionPass {
 
-  AMDGPULibCalls Simplifier;
-
   const TargetOptions Options;
 
+  AMDGPULibCalls Simplifier;
+
   public:
     static char ID; // Pass identification
 
-    AMDGPUSimplifyLibCalls(const TargetOptions &Opt = TargetOptions())
-      : FunctionPass(ID), Options(Opt) {
+    AMDGPUSimplifyLibCalls(const TargetOptions &Opt = TargetOptions(),
+                           const TargetMachine *TM = nullptr)
+      : FunctionPass(ID), Options(Opt), Simplifier(TM) {
       initializeAMDGPUSimplifyLibCallsPass(*PassRegistry::getPassRegistry());
     }
 
@@ -639,14 +650,6 @@ bool AMDGPULibCalls::fold(CallInst *CI, AliasAnalysis *AA) {
   // Ignore indirect calls.
   if (Callee == 0) return false;
 
-  FuncInfo FInfo;
-  if (!parseFunctionName(Callee->getName(), &FInfo))
-    return false;
-
-  // Further check the number of arguments to see if they match.
-  if (CI->getNumArgOperands() != FInfo.getNumArgs())
-    return false;
-
   BasicBlock *BB = CI->getParent();
   LLVMContext &Context = CI->getParent()->getContext();
   IRBuilder<> B(Context);
@@ -658,6 +661,21 @@ bool AMDGPULibCalls::fold(CallInst *CI, AliasAnalysis *AA) {
   if (const FPMathOperator *FPOp = dyn_cast<const FPMathOperator>(CI))
     B.setFastMathFlags(FPOp->getFastMathFlags());
 
+  switch (Callee->getIntrinsicID()) {
+  default:
+    break;
+  case Intrinsic::amdgcn_wavefrontsize:
+    return !EnablePreLink && fold_wavefrontsize(CI, B);
+  }
+
+  FuncInfo FInfo;
+  if (!parseFunctionName(Callee->getName(), &FInfo))
+    return false;
+
+  // Further check the number of arguments to see if they match.
+  if (CI->getNumArgOperands() != FInfo.getNumArgs())
+    return false;
+
   if (TDOFold(CI, FInfo))
     return true;
 
@@ -1371,6 +1389,29 @@ bool AMDGPULibCalls::fold_sincos(CallInst *CI, IRBuilder<> &B,
   return true;
 }
 
+bool AMDGPULibCalls::fold_wavefrontsize(CallInst *CI, IRBuilder<> &B) {
+  if (!TM)
+    return false;
+
+  StringRef CPU = TM->getTargetCPU();
+  StringRef Features = TM->getTargetFeatureString();
+  if ((CPU.empty() || CPU.equals_lower("generic")) &&
+      (Features.empty() ||
+       Features.find_lower("wavefrontsize") == StringRef::npos))
+    return false;
+
+  Function *F = CI->getParent()->getParent();
+  const GCNSubtarget &ST = TM->getSubtarget<GCNSubtarget>(*F);
+  unsigned N = ST.getWavefrontSize();
+
+  LLVM_DEBUG(errs() << "AMDIC: fold_wavefrontsize (" << *CI << ") with "
+               << N << "\n");
+
+  CI->replaceAllUsesWith(ConstantInt::get(B.getInt32Ty(), N));
+  CI->eraseFromParent();
+  return true;
+}
+
 // Get insertion point at entry.
 BasicBlock::iterator AMDGPULibCalls::getEntryIns(CallInst * UI) {
   Function * Func = UI->getParent()->getParent();
@@ -1680,8 +1721,9 @@ bool AMDGPULibCalls::evaluateCall(CallInst *aCI, FuncInfo &FInfo) {
 }
 
 // Public interface to the Simplify LibCalls pass.
-FunctionPass *llvm::createAMDGPUSimplifyLibCallsPass(const TargetOptions &Opt) {
-  return new AMDGPUSimplifyLibCalls(Opt);
+FunctionPass *llvm::createAMDGPUSimplifyLibCallsPass(const TargetOptions &Opt,
+                                                     const TargetMachine *TM) {
+  return new AMDGPUSimplifyLibCalls(Opt, TM);
 }
 
 FunctionPass *llvm::createAMDGPUUseNativeCallsPass() {
diff --git a/llvm/lib/Target/AMDGPU/AMDGPUTargetMachine.cpp b/llvm/lib/Target/AMDGPU/AMDGPUTargetMachine.cpp
index 41a075756ee..ae422940b25 100644
--- a/llvm/lib/Target/AMDGPU/AMDGPUTargetMachine.cpp
+++ b/llvm/lib/Target/AMDGPU/AMDGPUTargetMachine.cpp
@@ -432,7 +432,7 @@ void AMDGPUTargetMachine::adjustPassManager(PassManagerBuilder &Builder) {
       PM.add(llvm::createAMDGPUPropagateAttributesEarlyPass(this));
       PM.add(llvm::createAMDGPUUseNativeCallsPass());
       if (LibCallSimplify)
-        PM.add(llvm::createAMDGPUSimplifyLibCallsPass(Opt));
+        PM.add(llvm::createAMDGPUSimplifyLibCallsPass(Opt, this));
   });
 
   Builder.addExtension(