diff --git a/llvm/lib/Transforms/InstCombine/InstructionCombining.cpp b/llvm/lib/Transforms/InstCombine/InstructionCombining.cpp
--- a/llvm/lib/Transforms/InstCombine/InstructionCombining.cpp
+++ b/llvm/lib/Transforms/InstCombine/InstructionCombining.cpp
@@ -2224,6 +2224,59 @@
   if (Instruction *R = foldSelectGEP(GEP, Builder))
     return R;
 
+  // The definition of llvm.ptrmask(Ptr, Mask) is:
+  // (getelementptr i8, Ptr, (sub (and (ptrtoint Ptr), Mask), (ptrtoint Ptr)))
+  //
+  // llvm.ptrmask is preferable as it doesn't require transitioning from ptr ->
+  // int (and is generally easier to analyze).
+  // Don't do this for for vector of pointers, as llvm.ptrmask has weird
+  // definition for vectors.
+  if (!GEPType->isVectorTy() && GEPEltType->isIntegerTy(8) &&
+      GEP.getNumIndices() == 1) {
+    Value *Index = GEP.idx_begin()->get();
+    if (Index->hasOneUse()) {
+      Value *Ptr = GEP.getPointerOperand();
+      Value *Mask;
+      const APInt *CMask, *NotCMask;
+      Value *R = nullptr;
+      // (getelementptr i8, Ptr, (sub (and (ptrtoint Ptr), Mask), (ptrtoint Ptr)))
+      //      -> llvm.ptrmask(Ptr, Mask)
+      if (match(Index, m_Sub(m_OneUse(m_c_And(m_PtrToInt(m_Specific(Ptr)),
+                                              m_Value(Mask))),
+                             m_PtrToInt(m_Specific(Ptr)))))
+        R = Builder.CreateIntrinsic(Ptr->getType(), Intrinsic::ptrmask,
+                                    {Ptr, Mask});
+      // (getelementptr i8, Ptr (sub 0, (and (ptrtoint Ptr), CMask)))
+      //      -> llvm.ptrmask(Ptr, ~CMask)
+      //
+      // This is what __builtin_align_down generates.
+      else if (match(Index, m_Neg(m_OneUse(m_And(m_PtrToInt(m_Specific(Ptr)),
+                                                 m_APInt(CMask))))) &&
+               CMask->isMask())
+        R = Builder.CreateIntrinsic(
+            Ptr->getType(), Intrinsic::ptrmask,
+            {Ptr, ConstantInt::get(Index->getType(), ~(*CMask))});
+
+      // (getelementptr i8, Ptr (sub (and (add (ptrtoint Ptr), ~CMask), CMask), (ptrtoint Ptr)))
+      //      -> llvm.ptrmask((getelementptr i8, Ptr, ~CMask), CMask)
+      //
+      // This is what __builtin_align_up generates.
+      else if (match(Index,
+                     m_Sub(m_OneUse(
+                               m_And(m_OneUse(m_Add(m_PtrToInt(m_Specific(Ptr)),
+                                                    m_APInt(NotCMask))),
+                                     m_APInt(CMask))),
+                           m_PtrToInt(m_Specific(Ptr)))) &&
+               (*CMask) == ~(*NotCMask) && NotCMask->isMask())
+        R = Builder.CreateIntrinsic(
+            Ptr->getType(), Intrinsic::ptrmask,
+            {Builder.CreateGEP(GEP.getSourceElementType(), Ptr,
+                               ConstantInt::get(Index->getType(), *NotCMask)),
+             ConstantInt::get(Index->getType(), *CMask)});
+      if (R)
+        return replaceInstUsesWith(GEP, R);
+    }
+  }
   return nullptr;
 }
 
diff --git a/llvm/test/Transforms/InstCombine/to-ptrmask.ll b/llvm/test/Transforms/InstCombine/to-ptrmask.ll
--- a/llvm/test/Transforms/InstCombine/to-ptrmask.ll
+++ b/llvm/test/Transforms/InstCombine/to-ptrmask.ll
@@ -7,10 +7,7 @@
 define ptr @GEP_default_pattern_to_ptrmask(ptr %p, i64 %m) {
 ; CHECK-LABEL: define ptr @GEP_default_pattern_to_ptrmask
 ; CHECK-SAME: (ptr [[P:%.*]], i64 [[M:%.*]]) {
-; CHECK-NEXT:    [[PI:%.*]] = ptrtoint ptr [[P]] to i64
-; CHECK-NEXT:    [[PI_M:%.*]] = and i64 [[PI]], [[M]]
-; CHECK-NEXT:    [[PI_OFF:%.*]] = sub i64 [[PI_M]], [[PI]]
-; CHECK-NEXT:    [[PM:%.*]] = getelementptr i8, ptr [[P]], i64 [[PI_OFF]]
+; CHECK-NEXT:    [[PM:%.*]] = call ptr @llvm.ptrmask.p0.i64(ptr [[P]], i64 [[M]])
 ; CHECK-NEXT:    ret ptr [[PM]]
 ;
   %pi = ptrtoint ptr %p to i64
@@ -92,11 +89,8 @@
 ; CHECK-LABEL: define ptr @builtin_align_up_to_ptrmask
 ; CHECK-SAME: (ptr [[X:%.*]]) {
 ; CHECK-NEXT:  entry:
-; CHECK-NEXT:    [[INTPTR:%.*]] = ptrtoint ptr [[X]] to i64
-; CHECK-NEXT:    [[OVER_BOUNDARY:%.*]] = add i64 [[INTPTR]], 7
-; CHECK-NEXT:    [[ALIGNED_INTPTR:%.*]] = and i64 [[OVER_BOUNDARY]], -8
-; CHECK-NEXT:    [[DIFF:%.*]] = sub i64 [[ALIGNED_INTPTR]], [[INTPTR]]
-; CHECK-NEXT:    [[ALIGNED_RESULT:%.*]] = getelementptr inbounds i8, ptr [[X]], i64 [[DIFF]]
+; CHECK-NEXT:    [[TMP0:%.*]] = getelementptr i8, ptr [[X]], i64 7
+; CHECK-NEXT:    [[ALIGNED_RESULT:%.*]] = call ptr @llvm.ptrmask.p0.i64(ptr [[TMP0]], i64 -8)
 ; CHECK-NEXT:    ret ptr [[ALIGNED_RESULT]]
 ;
 entry:
@@ -174,10 +168,7 @@
 ; CHECK-LABEL: define ptr @builtin_align_down_to_ptrmask
 ; CHECK-SAME: (ptr [[X:%.*]]) {
 ; CHECK-NEXT:  entry:
-; CHECK-NEXT:    [[INTPTR:%.*]] = ptrtoint ptr [[X]] to i64
-; CHECK-NEXT:    [[AND:%.*]] = and i64 [[INTPTR]], 7
-; CHECK-NEXT:    [[DIFF:%.*]] = sub nsw i64 0, [[AND]]
-; CHECK-NEXT:    [[ALIGNED_RESULT:%.*]] = getelementptr inbounds i8, ptr [[X]], i64 [[DIFF]]
+; CHECK-NEXT:    [[ALIGNED_RESULT:%.*]] = call ptr @llvm.ptrmask.p0.i64(ptr [[X]], i64 -8)
 ; CHECK-NEXT:    ret ptr [[ALIGNED_RESULT]]
 ;
 entry: