[PATCH] D75790: [PowerPC] Fix compile time issue in recursive CTR analysis code

[Teresa Johnson via Phabricator via llvm-commits]

This revision was automatically updated to reflect the committed changes.
Closed by commit rG8f5e3c74b678: [PowerPC] Fix compile time issue in recursive CTR analysis code (authored by tejohnson).

Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D75790/new/

https://reviews.llvm.org/D75790

Files:
  llvm/lib/Target/PowerPC/PPCTargetTransformInfo.cpp
  llvm/lib/Target/PowerPC/PPCTargetTransformInfo.h


Index: llvm/lib/Target/PowerPC/PPCTargetTransformInfo.h
===================================================================
--- llvm/lib/Target/PowerPC/PPCTargetTransformInfo.h
+++ llvm/lib/Target/PowerPC/PPCTargetTransformInfo.h
@@ -33,7 +33,8 @@
 
   const PPCSubtarget *getST() const { return ST; }
   const PPCTargetLowering *getTLI() const { return TLI; }
-  bool mightUseCTR(BasicBlock *BB, TargetLibraryInfo *LibInfo);
+  bool mightUseCTR(BasicBlock *BB, TargetLibraryInfo *LibInfo,
+                   SmallPtrSetImpl<const Value *> &Visited);
 
 public:
   explicit PPCTTIImpl(const PPCTargetMachine *TM, const Function &F)
Index: llvm/lib/Target/PowerPC/PPCTargetTransformInfo.cpp
===================================================================
--- llvm/lib/Target/PowerPC/PPCTargetTransformInfo.cpp
+++ llvm/lib/Target/PowerPC/PPCTargetTransformInfo.cpp
@@ -217,8 +217,8 @@
   return BaseT::getUserCost(U, Operands);
 }
 
-bool PPCTTIImpl::mightUseCTR(BasicBlock *BB,
-                             TargetLibraryInfo *LibInfo) {
+bool PPCTTIImpl::mightUseCTR(BasicBlock *BB, TargetLibraryInfo *LibInfo,
+                             SmallPtrSetImpl<const Value *> &Visited) {
   const PPCTargetMachine &TM = ST->getTargetMachine();
 
   // Loop through the inline asm constraints and look for something that
@@ -237,8 +237,11 @@
 
   // Determining the address of a TLS variable results in a function call in
   // certain TLS models.
-  std::function<bool(const Value*)> memAddrUsesCTR =
-    [&memAddrUsesCTR, &TM](const Value *MemAddr) -> bool {
+  std::function<bool(const Value *)> memAddrUsesCTR =
+      [&memAddrUsesCTR, &TM, &Visited](const Value *MemAddr) -> bool {
+    // No need to traverse again if we already checked this operand.
+    if (!Visited.insert(MemAddr).second)
+      return false;
     const auto *GV = dyn_cast<GlobalValue>(MemAddr);
     if (!GV) {
       // Recurse to check for constants that refer to TLS global variables.
@@ -502,9 +505,10 @@
 
   // We don't want to spill/restore the counter register, and so we don't
   // want to use the counter register if the loop contains calls.
+  SmallPtrSet<const Value *, 4> Visited;
   for (Loop::block_iterator I = L->block_begin(), IE = L->block_end();
        I != IE; ++I)
-    if (mightUseCTR(*I, LibInfo))
+    if (mightUseCTR(*I, LibInfo, Visited))
       return false;
 
   SmallVector<BasicBlock*, 4> ExitingBlocks;


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