Run LICM pass after loop unrolling pass.
Runtime unrollng will introduce a runtime check in loop prologue.
If the unrolled loop is a inner loop, then the proglogue will be inside
the outer loop. LICM pass can help to promote the runtime check out if
the checked value is loop invariant.
llvm-svn: 231630
diff --git a/llvm/lib/Transforms/IPO/PassManagerBuilder.cpp b/llvm/lib/Transforms/IPO/PassManagerBuilder.cpp
index 21fa34d..7ff55a7 100644
--- a/llvm/lib/Transforms/IPO/PassManagerBuilder.cpp
+++ b/llvm/lib/Transforms/IPO/PassManagerBuilder.cpp
@@ -364,8 +364,14 @@
MPM.add(createCFGSimplificationPass());
MPM.add(createInstructionCombiningPass());
- if (!DisableUnrollLoops)
+ if (!DisableUnrollLoops) {
MPM.add(createLoopUnrollPass()); // Unroll small loops
+ // Runtime unrollng will introduce runtime check in loop prologue. If the
+ // unrolled loop is a inner loop, then the prologue will be inside the
+ // outer loop. LICM pass can help to promote the runtime check out if the
+ // checked value is loop invariant.
+ MPM.add(createLICMPass());
+ }
// After vectorization and unrolling, assume intrinsics may tell us more
// about pointer alignments.