[LoopVectorize] Rename pass options. NFC.

Rename:
NoUnrolling to InterleaveOnlyWhenForced
and
AlwaysVectorize to !VectorizeOnlyWhenForced

Contrary to what the name 'AlwaysVectorize' suggests, it does not
unconditionally vectorize all loops, but applies a cost model to
determine whether vectorization is profitable to all loops. Hence,
passing false will disable the cost model, except when a loop is marked
with llvm.loop.vectorize.enable. The 'OnlyWhenForced' suffix (suggested
by @hfinkel in D55716) better matches this behavior.

Similarly, 'NoUnrolling' disables the profitability cost model for
interleaving (a term to distinguish it from unrolling by the
LoopUnrollPass); rename it for consistency.

Differential Revision: https://reviews.llvm.org/D55785

llvm-svn: 349513

1 files changed, 11 insertions, 8 deletions

diff --git a/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp b/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp
index 0341cce214a..c74352cf703 100644
--- a/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp
+++ b/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp
@@ -1359,7 +1359,8 @@ static bool isExplicitVecOuterLoop(Loop *OuterLp,
     return false;
 
   Function *Fn = OuterLp->getHeader()->getParent();
-  if (!Hints.allowVectorization(Fn, OuterLp, false /*AlwaysVectorize*/)) {
+  if (!Hints.allowVectorization(Fn, OuterLp,
+                                true /*VectorizeOnlyWhenForced*/)) {
     LLVM_DEBUG(dbgs() << "LV: Loop hints prevent outer loop vectorization.\n");
     return false;
   }
@@ -1415,10 +1416,11 @@ struct LoopVectorize : public FunctionPass {
 
   LoopVectorizePass Impl;
 
-  explicit LoopVectorize(bool NoUnrolling = false, bool AlwaysVectorize = true)
+  explicit LoopVectorize(bool InterleaveOnlyWhenForced = false,
+                         bool VectorizeOnlyWhenForced = false)
       : FunctionPass(ID) {
-    Impl.DisableUnrolling = NoUnrolling;
-    Impl.AlwaysVectorize = AlwaysVectorize;
+    Impl.InterleaveOnlyWhenForced = InterleaveOnlyWhenForced;
+    Impl.VectorizeOnlyWhenForced = VectorizeOnlyWhenForced;
     initializeLoopVectorizePass(*PassRegistry::getPassRegistry());
   }
 
@@ -6022,8 +6024,9 @@ INITIALIZE_PASS_END(LoopVectorize, LV_NAME, lv_name, false, false)
 
 namespace llvm {
 
-Pass *createLoopVectorizePass(bool NoUnrolling, bool AlwaysVectorize) {
-  return new LoopVectorize(NoUnrolling, AlwaysVectorize);
+Pass *createLoopVectorizePass(bool InterleaveOnlyWhenForced,
+                              bool VectorizeOnlyWhenForced) {
+  return new LoopVectorize(InterleaveOnlyWhenForced, VectorizeOnlyWhenForced);
 }
 
 } // end namespace llvm
@@ -7141,7 +7144,7 @@ bool LoopVectorizePass::processLoop(Loop *L) {
                     << L->getHeader()->getParent()->getName() << "\" from "
                     << DebugLocStr << "\n");
 
-  LoopVectorizeHints Hints(L, DisableUnrolling, *ORE);
+  LoopVectorizeHints Hints(L, InterleaveOnlyWhenForced, *ORE);
 
   LLVM_DEBUG(
       dbgs() << "LV: Loop hints:"
@@ -7165,7 +7168,7 @@ bool LoopVectorizePass::processLoop(Loop *L) {
   // less verbose reporting vectorized loops and unvectorized loops that may
   // benefit from vectorization, respectively.
 
-  if (!Hints.allowVectorization(F, L, AlwaysVectorize)) {
+  if (!Hints.allowVectorization(F, L, VectorizeOnlyWhenForced)) {
     LLVM_DEBUG(dbgs() << "LV: Loop hints prevent vectorization.\n");
     return false;
   }