LoopVectorize: guard appending InstsToScalarize; fix bug

llvm/lib/Transforms/Vectorize/LoopVectorize.cpp

@@ -5821,7 +5821,8 @@ void LoopVectorizationCostModel::collectInstsToScalarize(ElementCount VF) {
         // invalid scalarization costs.
         // Do not apply discount logic if hacked cost is needed
         // for emulated masked memrefs.
-        if (!VF.isScalable() && !useEmulatedMaskMemRefHack(&I, VF) &&
+        if (!isScalarAfterVectorization(&I, VF) && !VF.isScalable() &&
+            !useEmulatedMaskMemRefHack(&I, VF) &&
             computePredInstDiscount(&I, ScalarCosts, VF) >= 0)
           ScalarCostsVF.insert(ScalarCosts.begin(), ScalarCosts.end());
         // Remember that BB will remain after vectorization.

llvm/test/Transforms/LoopVectorize/X86/pr55096-scalarize-add.ll

@@ -1,13 +1,48 @@
-; RUN: opt -passes=loop-vectorize -force-vector-width=2 -force-vector-interleave=1 -S %s | FileCheck %s
-
-; REQUIRES: asserts
-; XFAIL: *
-
-target triple = "x86_64-apple-macosx"
-
-; CHECK: vector.body
+; NOTE: Assertions have been autogenerated by utils/update_test_checks.py UTC_ARGS: --version 4
+; RUN: opt -mtriple=x86_64-apple-macosx -passes=loop-vectorize,simplifycfg,dce -force-vector-width=2 -force-vector-interleave=1 -S %s | FileCheck %s
 
 define void @test_pr55096(i64 %c, ptr %p) {
+; CHECK-LABEL: define void @test_pr55096(
+; CHECK-SAME: i64 [[C:%.*]], ptr [[P:%.*]]) {
+; CHECK-NEXT:  entry:
+; CHECK-NEXT:    [[BROADCAST_SPLATINSERT:%.*]] = insertelement <2 x i64> poison, i64 [[C]], i64 0
+; CHECK-NEXT:    [[BROADCAST_SPLAT:%.*]] = shufflevector <2 x i64> [[BROADCAST_SPLATINSERT]], <2 x i64> poison, <2 x i32> zeroinitializer
+; CHECK-NEXT:    br label [[VECTOR_BODY:%.*]]
+; CHECK:       vector.body:
+; CHECK-NEXT:    [[INDEX:%.*]] = phi i64 [ 0, [[VECTOR_PH:%.*]] ], [ [[INDEX_NEXT:%.*]], [[PRED_STORE_CONTINUE3:%.*]] ]
+; CHECK-NEXT:    [[VEC_IND:%.*]] = phi <2 x i64> [ <i64 122, i64 123>, [[VECTOR_PH]] ], [ [[VEC_IND_NEXT:%.*]], [[PRED_STORE_CONTINUE3]] ]
+; CHECK-NEXT:    [[DOTCAST:%.*]] = trunc i64 [[INDEX]] to i16
+; CHECK-NEXT:    [[TMP0:%.*]] = mul i16 [[DOTCAST]], 2008
+; CHECK-NEXT:    [[OFFSET_IDX:%.*]] = add i16 6229, [[TMP0]]
+; CHECK-NEXT:    [[TMP1:%.*]] = icmp ult <2 x i64> [[VEC_IND]], [[BROADCAST_SPLAT]]
+; CHECK-NEXT:    [[TMP2:%.*]] = xor <2 x i1> [[TMP1]], <i1 true, i1 true>
+; CHECK-NEXT:    [[TMP3:%.*]] = extractelement <2 x i1> [[TMP2]], i32 0
+; CHECK-NEXT:    br i1 [[TMP3]], label [[PRED_STORE_IF:%.*]], label [[PRED_STORE_CONTINUE:%.*]]
+; CHECK:       pred.store.if:
+; CHECK-NEXT:    [[TMP4:%.*]] = add i16 [[OFFSET_IDX]], 0
+; CHECK-NEXT:    [[TMP5:%.*]] = add i16 [[TMP4]], 2008
+; CHECK-NEXT:    [[TMP6:%.*]] = udiv i16 4943, [[TMP5]]
+; CHECK-NEXT:    [[TMP7:%.*]] = getelementptr inbounds i16, ptr [[P]], i16 [[TMP6]]
+; CHECK-NEXT:    store i16 0, ptr [[TMP7]], align 2
+; CHECK-NEXT:    br label [[PRED_STORE_CONTINUE]]
+; CHECK:       pred.store.continue:
+; CHECK-NEXT:    [[TMP9:%.*]] = extractelement <2 x i1> [[TMP2]], i32 1
+; CHECK-NEXT:    br i1 [[TMP9]], label [[PRED_STORE_IF2:%.*]], label [[PRED_STORE_CONTINUE3]]
+; CHECK:       pred.store.if2:
+; CHECK-NEXT:    [[TMP10:%.*]] = add i16 [[OFFSET_IDX]], 2008
+; CHECK-NEXT:    [[TMP11:%.*]] = add i16 [[TMP10]], 2008
+; CHECK-NEXT:    [[TMP12:%.*]] = udiv i16 4943, [[TMP11]]
+; CHECK-NEXT:    [[TMP13:%.*]] = getelementptr inbounds i16, ptr [[P]], i16 [[TMP12]]
+; CHECK-NEXT:    store i16 0, ptr [[TMP13]], align 2
+; CHECK-NEXT:    br label [[PRED_STORE_CONTINUE3]]
+; CHECK:       pred.store.continue3:
+; CHECK-NEXT:    [[INDEX_NEXT]] = add nuw i64 [[INDEX]], 2
+; CHECK-NEXT:    [[VEC_IND_NEXT]] = add <2 x i64> [[VEC_IND]], <i64 2, i64 2>
+; CHECK-NEXT:    [[TMP15:%.*]] = icmp eq i64 [[INDEX_NEXT]], 340
+; CHECK-NEXT:    br i1 [[TMP15]], label [[MIDDLE_BLOCK:%.*]], label [[VECTOR_BODY]], !llvm.loop [[LOOP0:![0-9]+]]
+; CHECK:       exit:
+; CHECK-NEXT:    ret void
+;
 entry:
   br label %loop.header
 
@@ -32,3 +67,8 @@ loop.latch:
 exit:
   ret void
 }
+;.
+; CHECK: [[LOOP0]] = distinct !{[[LOOP0]], [[META1:![0-9]+]], [[META2:![0-9]+]]}
+; CHECK: [[META1]] = !{!"llvm.loop.isvectorized", i32 1}
+; CHECK: [[META2]] = !{!"llvm.loop.unroll.runtime.disable"}
+;.