Move llvm::computeLoopSafetyInfo from LICM.cpp to LoopUtils.cpp. NFC

Move computeLoopSafetyInfo, defined in Transforms/Utils/LoopUtils.h,
into the corresponding LoopUtils.cpp, as opposed to LICM where it resides
at the moment. This will allow other functions from Transforms/Utils
to reference it.

llvm-svn: 325151

1 files changed, 37 insertions, 0 deletions

diff --git a/llvm/lib/Transforms/Utils/LoopUtils.cpp b/llvm/lib/Transforms/Utils/LoopUtils.cpp
index 75665cfb7e9..c9c50cd7384 100644
--- a/llvm/lib/Transforms/Utils/LoopUtils.cpp
+++ b/llvm/lib/Transforms/Utils/LoopUtils.cpp
@@ -1481,6 +1481,43 @@ void llvm::deleteDeadLoop(Loop *L, DominatorTree *DT = nullptr,
   }
 }
 
+/// Computes loop safety information, checks loop body & header
+/// for the possibility of may throw exception.
+///
+void llvm::computeLoopSafetyInfo(LoopSafetyInfo *SafetyInfo, Loop *CurLoop) {
+  assert(CurLoop != nullptr && "CurLoop cant be null");
+  BasicBlock *Header = CurLoop->getHeader();
+  // Setting default safety values.
+  SafetyInfo->MayThrow = false;
+  SafetyInfo->HeaderMayThrow = false;
+  // Iterate over header and compute safety info.
+  for (BasicBlock::iterator I = Header->begin(), E = Header->end();
+       (I != E) && !SafetyInfo->HeaderMayThrow; ++I)
+    SafetyInfo->HeaderMayThrow |=
+        !isGuaranteedToTransferExecutionToSuccessor(&*I);
+
+  SafetyInfo->MayThrow = SafetyInfo->HeaderMayThrow;
+  // Iterate over loop instructions and compute safety info.
+  // Skip header as it has been computed and stored in HeaderMayThrow.
+  // The first block in loopinfo.Blocks is guaranteed to be the header.
+  assert(Header == *CurLoop->getBlocks().begin() &&
+         "First block must be header");
+  for (Loop::block_iterator BB = std::next(CurLoop->block_begin()),
+                            BBE = CurLoop->block_end();
+       (BB != BBE) && !SafetyInfo->MayThrow; ++BB)
+    for (BasicBlock::iterator I = (*BB)->begin(), E = (*BB)->end();
+         (I != E) && !SafetyInfo->MayThrow; ++I)
+      SafetyInfo->MayThrow |= !isGuaranteedToTransferExecutionToSuccessor(&*I);
+
+  // Compute funclet colors if we might sink/hoist in a function with a funclet
+  // personality routine.
+  Function *Fn = CurLoop->getHeader()->getParent();
+  if (Fn->hasPersonalityFn())
+    if (Constant *PersonalityFn = Fn->getPersonalityFn())
+      if (isFuncletEHPersonality(classifyEHPersonality(PersonalityFn)))
+        SafetyInfo->BlockColors = colorEHFunclets(*Fn);
+}
+
 /// Returns true if the instruction in a loop is guaranteed to execute at least
 /// once.
 bool llvm::isGuaranteedToExecute(const Instruction &Inst,