From ab6cd2d498b6d929469dacc923043eec90a31fd3 Mon Sep 17 00:00:00 2001
From: Matt Arsenault <Matthew.Arsenault@amd.com>
Date: Sun, 30 Jul 2023 10:50:42 -0400
Subject: [PATCH] AMDGPU: Simplify early exit handling for libcall simplify

Early exit on intrinsics and don't duplicate indirect call
checks. Also let the IRBuilder constructor figure out the insert point
rather than doing it manually. Also avoid debug print about trying to
simplify calls in more unhandled scenarios.
---
 llvm/lib/Target/AMDGPU/AMDGPULibCalls.cpp | 81 +++++++----------------
 1 file changed, 24 insertions(+), 57 deletions(-)

diff --git a/llvm/lib/Target/AMDGPU/AMDGPULibCalls.cpp b/llvm/lib/Target/AMDGPU/AMDGPULibCalls.cpp
index de5c2d9acb0d3..674bd433cf8a7 100644
--- a/llvm/lib/Target/AMDGPU/AMDGPULibCalls.cpp
+++ b/llvm/lib/Target/AMDGPU/AMDGPULibCalls.cpp
@@ -500,6 +500,8 @@ bool AMDGPULibCalls::sincosUseNative(CallInst *aCI, const FuncInfo &FInfo) {
 bool AMDGPULibCalls::useNative(CallInst *aCI) {
   CI = aCI;
   Function *Callee = aCI->getCalledFunction();
+  if (!Callee)
+    return false;
 
   FuncInfo FInfo;
   if (!parseFunctionName(Callee->getName(), FInfo) || !FInfo.isMangled() ||
@@ -587,27 +589,18 @@ bool AMDGPULibCalls::fold_read_write_pipe(CallInst *CI, IRBuilder<> &B,
 bool AMDGPULibCalls::fold(CallInst *CI, AliasAnalysis *AA) {
   this->CI = CI;
   Function *Callee = CI->getCalledFunction();
-
   // Ignore indirect calls.
-  if (Callee == nullptr)
+  if (!Callee)
     return false;
 
-  BasicBlock *BB = CI->getParent();
-  LLVMContext &Context = CI->getParent()->getContext();
-  IRBuilder<> B(Context);
-
-  // Set the builder to the instruction after the call.
-  B.SetInsertPoint(BB, CI->getIterator());
-
-  // Copy fast flags from the original call.
-  if (const FPMathOperator *FPOp = dyn_cast<const FPMathOperator>(CI))
-    B.setFastMathFlags(FPOp->getFastMathFlags());
-
+  IRBuilder<> B(CI);
   switch (Callee->getIntrinsicID()) {
-  default:
+  case Intrinsic::not_intrinsic:
     break;
   case Intrinsic::amdgcn_wavefrontsize:
     return !EnablePreLink && fold_wavefrontsize(CI, B);
+  default:
+    return false;
   }
 
   FuncInfo FInfo;
@@ -618,6 +611,8 @@ bool AMDGPULibCalls::fold(CallInst *CI, AliasAnalysis *AA) {
   if (CI->arg_size() != FInfo.getNumArgs())
     return false;
 
+  LLVM_DEBUG(dbgs() << "AMDIC: try folding " << *CI << '\n');
+
   if (TDOFold(CI, FInfo))
     return true;
 
@@ -627,6 +622,10 @@ bool AMDGPULibCalls::fold(CallInst *CI, AliasAnalysis *AA) {
   if (isUnsafeMath(CI) && evaluateCall(CI, FInfo))
     return true;
 
+  // Copy fast flags from the original call.
+  if (const FPMathOperator *FPOp = dyn_cast<const FPMathOperator>(CI))
+    B.setFastMathFlags(FPOp->getFastMathFlags());
+
   // Specialized optimizations for each function call
   switch (FInfo.getId()) {
   case AMDGPULibFunc::EI_RECIP:
@@ -1664,19 +1663,10 @@ bool AMDGPUSimplifyLibCalls::runOnFunction(Function &F) {
       // Ignore non-calls.
       CallInst *CI = dyn_cast<CallInst>(I);
       ++I;
-      // Ignore intrinsics that do not become real instructions.
-      if (!CI || isa<DbgInfoIntrinsic>(CI) || CI->isLifetimeStartOrEnd())
-        continue;
-
-      // Ignore indirect calls.
-      Function *Callee = CI->getCalledFunction();
-      if (Callee == nullptr)
-        continue;
-
-      LLVM_DEBUG(dbgs() << "AMDIC: try folding " << *CI << "\n";
-                 dbgs().flush());
-      if(Simplifier.fold(CI, AA))
-        Changed = true;
+      if (CI) {
+        if (Simplifier.fold(CI, AA))
+          Changed = true;
+      }
     }
   }
   return Changed;
@@ -1698,19 +1688,11 @@ PreservedAnalyses AMDGPUSimplifyLibCallsPass::run(Function &F,
       // Ignore non-calls.
       CallInst *CI = dyn_cast<CallInst>(I);
       ++I;
-      // Ignore intrinsics that do not become real instructions.
-      if (!CI || isa<DbgInfoIntrinsic>(CI) || CI->isLifetimeStartOrEnd())
-        continue;
-
-      // Ignore indirect calls.
-      Function *Callee = CI->getCalledFunction();
-      if (Callee == nullptr)
-        continue;
-
-      LLVM_DEBUG(dbgs() << "AMDIC: try folding " << *CI << "\n";
-                 dbgs().flush());
-      if (Simplifier.fold(CI, AA))
-        Changed = true;
+
+      if (CI) {
+        if (Simplifier.fold(CI, AA))
+          Changed = true;
+      }
     }
   }
   return Changed ? PreservedAnalyses::none() : PreservedAnalyses::all();
@@ -1726,14 +1708,7 @@ bool AMDGPUUseNativeCalls::runOnFunction(Function &F) {
       // Ignore non-calls.
       CallInst *CI = dyn_cast<CallInst>(I);
       ++I;
-      if (!CI) continue;
-
-      // Ignore indirect calls.
-      Function *Callee = CI->getCalledFunction();
-      if (Callee == nullptr)
-        continue;
-
-      if (Simplifier.useNative(CI))
+      if (CI && Simplifier.useNative(CI))
         Changed = true;
     }
   }
@@ -1754,15 +1729,7 @@ PreservedAnalyses AMDGPUUseNativeCallsPass::run(Function &F,
       // Ignore non-calls.
       CallInst *CI = dyn_cast<CallInst>(I);
       ++I;
-      if (!CI)
-        continue;
-
-      // Ignore indirect calls.
-      Function *Callee = CI->getCalledFunction();
-      if (Callee == nullptr)
-        continue;
-
-      if (Simplifier.useNative(CI))
+      if (CI && Simplifier.useNative(CI))
         Changed = true;
     }
   }