diff --git a/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp b/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp
--- a/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp
+++ b/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp
@@ -2822,7 +2822,8 @@
       return;
 
   assert(!(SCEVCheckBlock->getParent()->hasOptSize() ||
-           OptForSizeBasedOnProfile) &&
+           (OptForSizeBasedOnProfile &&
+            Cost->Hints->getForce() != LoopVectorizeHints::FK_Enabled)) &&
          "Cannot SCEV check stride or overflow when optimizing for size");
 
   SCEVCheckBlock->setName("vector.scevcheck");
@@ -7913,12 +7914,17 @@
     BlockFrequencyInfo *BFI, TargetTransformInfo *TTI, TargetLibraryInfo *TLI,
     AssumptionCache *AC, LoopInfo *LI, ScalarEvolution *SE, DominatorTree *DT,
     LoopVectorizationLegality &LVL) {
-  bool OptSize =
-      F->hasOptSize() || llvm::shouldOptimizeForSize(L->getHeader(), PSI, BFI,
-                                                     PGSOQueryType::IRPass);
   // 1) OptSize takes precedence over all other options, i.e. if this is set,
   // don't look at hints or options, and don't request a scalar epilogue.
-  if (OptSize)
+  // (For PGSO, as shouldOptimizeForSize isn't currently accessible from
+  // LoopAccessInfo (due to code dependency and not being able to reliably get
+  // PSI/BFI from a loop analysis under NPM), we cannot suppress the collection
+  // of strides in LoopAccessInfo::analyzeLoop() and vectorize without
+  // versioning when the vectorization is forced, unlike hasOptSize. So revert
+  // back to the old way and vectorize with versioning when forced. See D81345.)
+  if (F->hasOptSize() || (llvm::shouldOptimizeForSize(L->getHeader(), PSI, BFI,
+                                                      PGSOQueryType::IRPass) &&
+                          Hints.getForce() != LoopVectorizeHints::FK_Enabled))
     return CM_ScalarEpilogueNotAllowedOptSize;
 
   bool PredicateOptDisabled = PreferPredicateOverEpilog.getNumOccurrences() &&
diff --git a/llvm/test/Transforms/LoopVectorize/optsize.ll b/llvm/test/Transforms/LoopVectorize/optsize.ll
--- a/llvm/test/Transforms/LoopVectorize/optsize.ll
+++ b/llvm/test/Transforms/LoopVectorize/optsize.ll
@@ -284,6 +284,34 @@
   ret void
 }
 
+; Vectorize with versioning for unit stride for PGSO and enabled vectorization.
+;
+define void @stride1_pgso(i16* noalias %B, i32 %BStride) !prof !14 {
+; CHECK-LABEL: @stride1_pgso(
+; CHECK: vector.body
+;
+; PGSO-LABEL: @stride1_pgso(
+; PGSO: vector.body
+;
+; NPGSO-LABEL: @stride1_pgso(
+; NPGSO: vector.body
+
+entry:
+  br label %for.body
+
+for.body:
+  %iv = phi i32 [ %iv.next, %for.body ], [ 0, %entry ]
+  %mulB = mul nsw i32 %iv, %BStride
+  %gepOfB = getelementptr inbounds i16, i16* %B, i32 %mulB
+  store i16 42, i16* %gepOfB, align 4
+  %iv.next = add nuw nsw i32 %iv, 1
+  %exitcond = icmp eq i32 %iv.next, 1025
+  br i1 %exitcond, label %for.end, label %for.body, !llvm.loop !15
+
+for.end:
+  ret void
+}
+
 ; PR46652: Check that the need for stride==1 check prevents vectorizing a loop
 ; having tiny trip count, when compiling w/o -Os/-Oz.
 ; CHECK-LABEL: @pr46652