fixup! Setting the metadata outside the LoopVectorizeHints

And use the string value to represent tail-folding style (again).

Author: mshockwave

llvm/include/llvm/Transforms/Vectorize/LoopVectorizationLegality.h

@@ -64,8 +64,7 @@ class LoopVectorizeHints {
     HK_FORCE,
     HK_ISVECTORIZED,
     HK_PREDICATE,
-    HK_SCALABLE,
-    HK_TAILFOLDING
+    HK_SCALABLE
   };
 
   /// Hint - associates name and validation with the hint value.
@@ -92,9 +91,6 @@ class LoopVectorizeHints {
   /// Already Vectorized
   Hint IsVectorized;
 
-  /// Tail folding style of a vectorized loop.
-  Hint TailFoldingStyle;
-
   /// Vector Predicate
   Hint Predicate;
 
@@ -125,12 +121,6 @@ class LoopVectorizeHints {
     SK_PreferScalable = 1
   };
 
-  enum TailFoldingKind {
-    TFK_Unspecified = -1,
-    /// Tail folding with explicit vector length intrinsics.
-    TFK_EVL = 0
-  };
-
   LoopVectorizeHints(const Loop *L, bool InterleaveOnlyWhenForced,
                      OptimizationRemarkEmitter &ORE,
                      const TargetTransformInfo *TTI = nullptr);
@@ -141,10 +131,6 @@ class LoopVectorizeHints {
   bool allowVectorization(Function *F, Loop *L,
                           bool VectorizeOnlyWhenForced) const;
 
-  /// Mark the loop as being vectorized with a specific tail folding style.
-  void setVectorizedTailFoldingStyle(TailFoldingKind Kind);
-  void setEVLVectorized() { setVectorizedTailFoldingStyle(TFK_EVL); }
-
   /// Dumps all the hint information.
   void emitRemarkWithHints() const;
 
@@ -176,14 +162,6 @@ class LoopVectorizeHints {
     return (ScalableForceKind)Scalable.Value == SK_FixedWidthOnly;
   }
 
-  /// \return the tail folding style of a vectorized loop.
-  TailFoldingKind getVectorizedTailFoldingStyle() const {
-    return (TailFoldingKind)TailFoldingStyle.Value;
-  }
-  bool isEVLVectorized() const {
-    return getVectorizedTailFoldingStyle() == TFK_EVL;
-  }
-
   /// If hints are provided that force vectorization, use the AlwaysPrint
   /// pass name to force the frontend to print the diagnostic.
   const char *vectorizeAnalysisPassName() const;

llvm/lib/Transforms/Vectorize/LoopVectorizationLegality.cpp

@@ -94,8 +94,6 @@ bool LoopVectorizeHints::Hint::validate(unsigned Val) {
     return isPowerOf2_32(Val) && Val <= MaxInterleaveFactor;
   case HK_FORCE:
     return (Val <= 1);
-  case HK_TAILFOLDING:
-    return Val == 0;
   case HK_ISVECTORIZED:
   case HK_PREDICATE:
   case HK_SCALABLE:
@@ -112,8 +110,6 @@ LoopVectorizeHints::LoopVectorizeHints(const Loop *L,
       Interleave("interleave.count", InterleaveOnlyWhenForced, HK_INTERLEAVE),
       Force("vectorize.enable", FK_Undefined, HK_FORCE),
       IsVectorized("isvectorized", 0, HK_ISVECTORIZED),
-      TailFoldingStyle("isvectorized.tailfoldingstyle", TFK_Unspecified,
-                       HK_TAILFOLDING),
       Predicate("vectorize.predicate.enable", FK_Undefined, HK_PREDICATE),
       Scalable("vectorize.scalable.enable", SK_Unspecified, HK_SCALABLE),
       TheLoop(L), ORE(ORE) {
@@ -158,14 +154,6 @@ LoopVectorizeHints::LoopVectorizeHints(const Loop *L,
     // nothing more that we can do.
     IsVectorized.Value =
         getWidth() == ElementCount::getFixed(1) && getInterleave() == 1;
-
-  if ((LoopVectorizeHints::TailFoldingKind)TailFoldingStyle.Value !=
-          TFK_Unspecified &&
-      !IsVectorized.Value)
-    // If the loop is not vectorized, do not attach the tail folding style
-    // metadata.
-    TailFoldingStyle.Value = TFK_Unspecified;
-
   LLVM_DEBUG(if (InterleaveOnlyWhenForced && getInterleave() == 1) dbgs()
              << "LV: Interleaving disabled by the pass manager\n");
 }
@@ -189,24 +177,6 @@ void LoopVectorizeHints::setAlreadyVectorized() {
   IsVectorized.Value = 1;
 }
 
-void LoopVectorizeHints::setVectorizedTailFoldingStyle(TailFoldingKind Kind) {
-  if (Kind == TFK_Unspecified)
-    return;
-
-  LLVMContext &Context = TheLoop->getHeader()->getContext();
-  MDNode *TailFoldingMD = MDNode::get(
-      Context,
-      {MDString::get(Context, "llvm.loop.isvectorized.tailfoldingstyle"),
-       ConstantAsMetadata::get(ConstantInt::get(Context, APInt(32, Kind)))});
-  MDNode *LoopID = TheLoop->getLoopID();
-  MDNode *NewLoopID =
-      makePostTransformationMetadata(Context, LoopID, {}, {TailFoldingMD});
-  TheLoop->setLoopID(NewLoopID);
-
-  // Update internal cache.
-  TailFoldingStyle.Value = Kind;
-}
-
 bool LoopVectorizeHints::allowVectorization(
     Function *F, Loop *L, bool VectorizeOnlyWhenForced) const {
   if (getForce() == LoopVectorizeHints::FK_Disabled) {
@@ -330,9 +300,8 @@ void LoopVectorizeHints::setHint(StringRef Name, Metadata *Arg) {
     return;
   unsigned Val = C->getZExtValue();
 
-  Hint *Hints[] = {&Width,        &Interleave,       &Force,
-                   &IsVectorized, &TailFoldingStyle, &Predicate,
-                   &Scalable};
+  Hint *Hints[] = {&Width,        &Interleave, &Force,
+                   &IsVectorized, &Predicate,  &Scalable};
   for (auto *H : Hints) {
     if (Name == H->Name) {
       if (H->validate(Val))

llvm/lib/Transforms/Vectorize/LoopVectorize.cpp

@@ -7830,16 +7830,24 @@ DenseMap<const SCEV *, Value *> LoopVectorizationPlanner::executePlan(
       Hints.setAlreadyVectorized();
 
       // Check if it's EVL-vectorized and mark the corresponding metadata.
-      // Note that we could have done this during the codegen of
-      // ExplictVectorLength, but the enclosing vector loop was not in a good
-      // shape for us to attach the metadata.
-      if (any_of(*HeaderVPBB, [](const VPRecipeBase &Recipe) {
+      bool IsEVLVectorized =
+          llvm::any_of(*HeaderVPBB, [](const VPRecipeBase &Recipe) {
             // Looking for the ExplictVectorLength VPInstruction.
             if (const auto *VI = dyn_cast<VPInstruction>(&Recipe))
               return VI->getOpcode() == VPInstruction::ExplicitVectorLength;
             return false;
-          }))
-        Hints.setEVLVectorized();
+          });
+      if (IsEVLVectorized) {
+        LLVMContext &Context = L->getHeader()->getContext();
+        MDNode *LoopID = L->getLoopID();
+        auto *IsEVLVectorizedMD = MDNode::get(
+            Context,
+            {MDString::get(Context, "llvm.loop.isvectorized.tailfoldingstyle"),
+             MDString::get(Context, "evl")});
+        MDNode *NewLoopID = makePostTransformationMetadata(Context, LoopID, {},
+                                                           {IsEVLVectorizedMD});
+        L->setLoopID(NewLoopID);
+      }
     }
     TargetTransformInfo::UnrollingPreferences UP;
     TTI.getUnrollingPreferences(L, *PSE.getSE(), UP, ORE);

llvm/test/Transforms/LoopVectorize/RISCV/truncate-to-minimal-bitwidth-evl-crash.ll

@@ -54,7 +54,7 @@ define void @truncate_to_minimal_bitwidths_widen_cast_recipe(ptr %src) {
 ; CHECK-NEXT:    store i8 [[CONV36]], ptr null, align 1
 ; CHECK-NEXT:    [[IV_NEXT]] = add i64 [[IV1]], 1
 ; CHECK-NEXT:    [[EC:%.*]] = icmp eq i64 [[IV1]], 8
-; CHECK-NEXT:    br i1 [[EC]], label %[[EXIT]], label %[[LOOP]], !llvm.loop [[LOOP3:![0-9]+]]
+; CHECK-NEXT:    br i1 [[EC]], label %[[EXIT]], label %[[LOOP]], !llvm.loop [[LOOP4:![0-9]+]]
 ; CHECK:       [[EXIT]]:
 ; CHECK-NEXT:    ret void
 ;
@@ -80,7 +80,7 @@ exit:                                             ; preds = %loop
 ;.
 ; CHECK: [[LOOP0]] = distinct !{[[LOOP0]], [[META1:![0-9]+]], [[META2:![0-9]+]], [[META3:![0-9]+]]}
 ; CHECK: [[META1]] = !{!"llvm.loop.isvectorized", i32 1}
-; CHECK: [[META2]] = !{!"llvm.loop.isvectorized.tailfoldingstyle", i32 0}
+; CHECK: [[META2]] = !{!"llvm.loop.isvectorized.tailfoldingstyle", !"evl"}
 ; CHECK: [[META3]] = !{!"llvm.loop.unroll.runtime.disable"}
 ; CHECK: [[LOOP4]] = distinct !{[[LOOP4]], [[META3]], [[META1]]}
 ;.

llvm/test/Transforms/LoopVectorize/RISCV/type-info-cache-evl-crash.ll

@@ -115,7 +115,7 @@ exit:
 ; CHECK: [[META4]] = distinct !{[[META4]], [[META2]]}
 ; CHECK: [[LOOP5]] = distinct !{[[LOOP5]], [[META6:![0-9]+]], [[META7:![0-9]+]], [[META8:![0-9]+]]}
 ; CHECK: [[META6]] = !{!"llvm.loop.isvectorized", i32 1}
-; CHECK: [[META7]] = !{!"llvm.loop.isvectorized.tailfoldingstyle", i32 0}
+; CHECK: [[META7]] = !{!"llvm.loop.isvectorized.tailfoldingstyle", !"evl"}
 ; CHECK: [[META8]] = !{!"llvm.loop.unroll.runtime.disable"}
 ; CHECK: [[LOOP9]] = distinct !{[[LOOP9]], [[META6]]}
 ;.

llvm/test/Transforms/LoopVectorize/RISCV/vectorize-force-tail-with-evl-bin-unary-ops-args.ll

@@ -1746,7 +1746,7 @@ finish.loopexit:
 ;.
 ; IF-EVL: [[LOOP0]] = distinct !{[[LOOP0]], [[META1:![0-9]+]], [[META2:![0-9]+]], [[META3:![0-9]+]]}
 ; IF-EVL: [[META1]] = !{!"llvm.loop.isvectorized", i32 1}
-; IF-EVL: [[META2]] = !{!"llvm.loop.isvectorized.tailfoldingstyle", i32 0}
+; IF-EVL: [[META2]] = !{!"llvm.loop.isvectorized.tailfoldingstyle", !"evl"}
 ; IF-EVL: [[META3]] = !{!"llvm.loop.unroll.runtime.disable"}
 ; IF-EVL: [[LOOP4]] = distinct !{[[LOOP4]], [[META1]]}
 ; IF-EVL: [[LOOP5]] = distinct !{[[LOOP5]], [[META1]], [[META2]], [[META3]]}

llvm/test/Transforms/LoopVectorize/RISCV/vectorize-force-tail-with-evl-call-intrinsics.ll

@@ -1048,7 +1048,7 @@ declare i32 @llvm.abs.i32(i32, i1 immarg)
 ;.
 ; IF-EVL: [[LOOP0]] = distinct !{[[LOOP0]], [[META1:![0-9]+]], [[META2:![0-9]+]], [[META3:![0-9]+]]}
 ; IF-EVL: [[META1]] = !{!"llvm.loop.isvectorized", i32 1}
-; IF-EVL: [[META2]] = !{!"llvm.loop.isvectorized.tailfoldingstyle", i32 0}
+; IF-EVL: [[META2]] = !{!"llvm.loop.isvectorized.tailfoldingstyle", !"evl"}
 ; IF-EVL: [[META3]] = !{!"llvm.loop.unroll.runtime.disable"}
 ; IF-EVL: [[LOOP4]] = distinct !{[[LOOP4]], [[META1]]}
 ; IF-EVL: [[LOOP5]] = distinct !{[[LOOP5]], [[META1]], [[META2]], [[META3]]}

llvm/test/Transforms/LoopVectorize/RISCV/vectorize-force-tail-with-evl-cast-intrinsics.ll

@@ -1056,7 +1056,7 @@ exit:
 ; IF-EVL: [[META4]] = distinct !{[[META4]], [[META2]]}
 ; IF-EVL: [[LOOP5]] = distinct !{[[LOOP5]], [[META6:![0-9]+]], [[META7:![0-9]+]], [[META8:![0-9]+]]}
 ; IF-EVL: [[META6]] = !{!"llvm.loop.isvectorized", i32 1}
-; IF-EVL: [[META7]] = !{!"llvm.loop.isvectorized.tailfoldingstyle", i32 0}
+; IF-EVL: [[META7]] = !{!"llvm.loop.isvectorized.tailfoldingstyle", !"evl"}
 ; IF-EVL: [[META8]] = !{!"llvm.loop.unroll.runtime.disable"}
 ; IF-EVL: [[LOOP9]] = distinct !{[[LOOP9]], [[META6]]}
 ; IF-EVL: [[META10]] = !{[[META11:![0-9]+]]}

llvm/test/Transforms/LoopVectorize/RISCV/vectorize-force-tail-with-evl-cond-reduction.ll

@@ -928,7 +928,7 @@ for.end:
 ;.
 ; IF-EVL-OUTLOOP: [[LOOP0]] = distinct !{[[LOOP0]], [[META1:![0-9]+]], [[META2:![0-9]+]], [[META3:![0-9]+]]}
 ; IF-EVL-OUTLOOP: [[META1]] = !{!"llvm.loop.isvectorized", i32 1}
-; IF-EVL-OUTLOOP: [[META2]] = !{!"llvm.loop.isvectorized.tailfoldingstyle", i32 0}
+; IF-EVL-OUTLOOP: [[META2]] = !{!"llvm.loop.isvectorized.tailfoldingstyle", !"evl"}
 ; IF-EVL-OUTLOOP: [[META3]] = !{!"llvm.loop.unroll.runtime.disable"}
 ; IF-EVL-OUTLOOP: [[LOOP4]] = distinct !{[[LOOP4]], [[META3]], [[META1]]}
 ; IF-EVL-OUTLOOP: [[LOOP5]] = distinct !{[[LOOP5]], [[META1]], [[META2]], [[META3]]}
@@ -938,7 +938,7 @@ for.end:
 ;.
 ; IF-EVL-INLOOP: [[LOOP0]] = distinct !{[[LOOP0]], [[META1:![0-9]+]], [[META2:![0-9]+]], [[META3:![0-9]+]]}
 ; IF-EVL-INLOOP: [[META1]] = !{!"llvm.loop.isvectorized", i32 1}
-; IF-EVL-INLOOP: [[META2]] = !{!"llvm.loop.isvectorized.tailfoldingstyle", i32 0}
+; IF-EVL-INLOOP: [[META2]] = !{!"llvm.loop.isvectorized.tailfoldingstyle", !"evl"}
 ; IF-EVL-INLOOP: [[META3]] = !{!"llvm.loop.unroll.runtime.disable"}
 ; IF-EVL-INLOOP: [[LOOP4]] = distinct !{[[LOOP4]], [[META3]], [[META1]]}
 ; IF-EVL-INLOOP: [[LOOP5]] = distinct !{[[LOOP5]], [[META1]], [[META2]], [[META3]]}

llvm/test/Transforms/LoopVectorize/RISCV/vectorize-force-tail-with-evl-div.ll

@@ -392,7 +392,7 @@ exit:
 ;.
 ; IF-EVL: [[LOOP0]] = distinct !{[[LOOP0]], [[META1:![0-9]+]], [[META2:![0-9]+]], [[META3:![0-9]+]]}
 ; IF-EVL: [[META1]] = !{!"llvm.loop.isvectorized", i32 1}
-; IF-EVL: [[META2]] = !{!"llvm.loop.isvectorized.tailfoldingstyle", i32 0}
+; IF-EVL: [[META2]] = !{!"llvm.loop.isvectorized.tailfoldingstyle", !"evl"}
 ; IF-EVL: [[META3]] = !{!"llvm.loop.unroll.runtime.disable"}
 ; IF-EVL: [[LOOP4]] = distinct !{[[LOOP4]], [[META3]], [[META1]]}
 ; IF-EVL: [[LOOP5]] = distinct !{[[LOOP5]], [[META1]], [[META2]], [[META3]]}