[BPI] Consider deoptimize calls as "unreachable"

Summary:
Calls to @llvm.experimental.deoptimize are expected to "never execute",
so optimize them as such.

Reviewers: chandlerc

Subscribers: junbuml, mcrosier, llvm-commits

Differential Revision: http://reviews.llvm.org/D19095

llvm-svn: 266654

1 files changed, 6 insertions, 1 deletions

diff --git a/llvm/lib/Analysis/BranchProbabilityInfo.cpp b/llvm/lib/Analysis/BranchProbabilityInfo.cpp
index 8512391d5ee..b431e621622 100644
--- a/llvm/lib/Analysis/BranchProbabilityInfo.cpp
+++ b/llvm/lib/Analysis/BranchProbabilityInfo.cpp
@@ -115,7 +115,12 @@ static const uint32_t IH_NONTAKEN_WEIGHT = 1;
 bool BranchProbabilityInfo::calcUnreachableHeuristics(const BasicBlock *BB) {
   const TerminatorInst *TI = BB->getTerminator();
   if (TI->getNumSuccessors() == 0) {
-    if (isa<UnreachableInst>(TI))
+    if (isa<UnreachableInst>(TI) ||
+        // If this block is terminated by a call to
+        // @llvm.experimental.deoptimize then treat it like an unreachable since
+        // the @llvm.experimental.deoptimize call is expected to practically
+        // never execute.
+        BB->getTerminatingDeoptimizeCall())
       PostDominatedByUnreachable.insert(BB);
     return false;
   }