Enable redundant phi elimination after LSR.

This will be more important as we extend the LSR pass in ways that don't rely on the formula solver. In particular, we need it for constructing IV chains.

llvm-svn: 147724

diff --git a/llvm/lib/Transforms/Scalar/LoopStrengthReduce.cpp b/llvm/lib/Transforms/Scalar/LoopStrengthReduce.cpp
index 8f3a5ab..c61714d 100644 (file)
--- a/llvm/lib/Transforms/Scalar/LoopStrengthReduce.cpp
+++ b/llvm/lib/Transforms/Scalar/LoopStrengthReduce.cpp
@@ -86,8 +86,10 @@ static cl::opt<bool> EnableRetry(
 // Temporary flag to cleanup congruent phis after LSR phi expansion.
 // It's currently disabled until we can determine whether it's truly useful or
 // not. The flag should be removed after the v3.0 release.
+// This is now needed for ivchains.
 static cl::opt<bool> EnablePhiElim(
-  "enable-lsr-phielim", cl::Hidden, cl::desc("Enable LSR phi elimination"));
+  "enable-lsr-phielim", cl::Hidden, cl::init(true),
+  cl::desc("Enable LSR phi elimination"));
 
 namespace {