diff --git a/llvm/lib/Transforms/InstCombine/InstCombineCalls.cpp b/llvm/lib/Transforms/InstCombine/InstCombineCalls.cpp
index 436cdbff75669..b42f0ca296fc5 100644
--- a/llvm/lib/Transforms/InstCombine/InstCombineCalls.cpp
+++ b/llvm/lib/Transforms/InstCombine/InstCombineCalls.cpp
@@ -2643,13 +2643,14 @@ Instruction *InstCombinerImpl::visitCallInst(CallInst &CI) {
     // (sign|resign) + (auth|resign) can be folded by omitting the middle
     // sign+auth component if the key and discriminator match.
     bool NeedSign = II->getIntrinsicID() == Intrinsic::ptrauth_resign;
+    Value *Ptr = II->getArgOperand(0);
     Value *Key = II->getArgOperand(1);
     Value *Disc = II->getArgOperand(2);
 
     // AuthKey will be the key we need to end up authenticating against in
     // whatever we replace this sequence with.
     Value *AuthKey = nullptr, *AuthDisc = nullptr, *BasePtr;
-    if (auto CI = dyn_cast<CallBase>(II->getArgOperand(0))) {
+    if (const auto *CI = dyn_cast<CallBase>(Ptr)) {
       BasePtr = CI->getArgOperand(0);
       if (CI->getIntrinsicID() == Intrinsic::ptrauth_sign) {
         if (CI->getArgOperand(1) != Key || CI->getArgOperand(2) != Disc)
@@ -2661,6 +2662,27 @@ Instruction *InstCombinerImpl::visitCallInst(CallInst &CI) {
         AuthDisc = CI->getArgOperand(2);
       } else
         break;
+    } else if (const auto *PtrToInt = dyn_cast<PtrToIntOperator>(Ptr)) {
+      // ptrauth constants are equivalent to a call to @llvm.ptrauth.sign for
+      // our purposes, so check for that too.
+      const auto *CPA = dyn_cast<ConstantPtrAuth>(PtrToInt->getOperand(0));
+      if (!CPA || !CPA->isKnownCompatibleWith(Key, Disc, DL))
+        break;
+
+      // resign(ptrauth(p,ks,ds),ks,ds,kr,dr) -> ptrauth(p,kr,dr)
+      if (NeedSign && isa<ConstantInt>(II->getArgOperand(4))) {
+        auto *SignKey = cast<ConstantInt>(II->getArgOperand(3));
+        auto *SignDisc = cast<ConstantInt>(II->getArgOperand(4));
+        auto *SignAddrDisc = ConstantPointerNull::get(Builder.getPtrTy());
+        auto *NewCPA = ConstantPtrAuth::get(CPA->getPointer(), SignKey,
+                                            SignDisc, SignAddrDisc);
+        replaceInstUsesWith(
+            *II, ConstantExpr::getPointerCast(NewCPA, II->getType()));
+        return eraseInstFromFunction(*II);
+      }
+
+      // auth(ptrauth(p,k,d),k,d) -> p
+      BasePtr = Builder.CreatePtrToInt(CPA->getPointer(), II->getType());
     } else
       break;
 
@@ -2677,8 +2699,7 @@ Instruction *InstCombinerImpl::visitCallInst(CallInst &CI) {
     } else {
       // sign(0) + auth(0) = nop
       replaceInstUsesWith(*II, BasePtr);
-      eraseInstFromFunction(*II);
-      return nullptr;
+      return eraseInstFromFunction(*II);
     }
 
     SmallVector<Value *, 4> CallArgs;
diff --git a/llvm/test/Transforms/InstCombine/ptrauth-intrinsics.ll b/llvm/test/Transforms/InstCombine/ptrauth-intrinsics.ll
index da0f724abfde4..208e162ac9416 100644
--- a/llvm/test/Transforms/InstCombine/ptrauth-intrinsics.ll
+++ b/llvm/test/Transforms/InstCombine/ptrauth-intrinsics.ll
@@ -12,6 +12,27 @@ define i64 @test_ptrauth_nop(ptr %p) {
   ret i64 %authed
 }
 
+declare void @foo()
+declare void @bar()
+
+define i64 @test_ptrauth_nop_constant() {
+; CHECK-LABEL: @test_ptrauth_nop_constant(
+; CHECK-NEXT:    ret i64 ptrtoint (ptr @foo to i64)
+;
+  %authed = call i64 @llvm.ptrauth.auth(i64 ptrtoint(ptr ptrauth(ptr @foo, i32 1, i64 1234) to i64), i32 1, i64 1234)
+  ret i64 %authed
+}
+
+define i64 @test_ptrauth_nop_constant_addrdisc() {
+; CHECK-LABEL: @test_ptrauth_nop_constant_addrdisc(
+; CHECK-NEXT:    ret i64 ptrtoint (ptr @foo to i64)
+;
+  %addr = ptrtoint ptr @foo to i64
+  %blended = call i64 @llvm.ptrauth.blend(i64 %addr, i64 1234)
+  %authed = call i64 @llvm.ptrauth.auth(i64 ptrtoint(ptr ptrauth(ptr @foo, i32 1, i64 1234, ptr @foo) to i64), i32 1, i64 %blended)
+  ret i64 %authed
+}
+
 define i64 @test_ptrauth_nop_mismatch(ptr %p) {
 ; CHECK-LABEL: @test_ptrauth_nop_mismatch(
 ; CHECK-NEXT:    [[TMP0:%.*]] = ptrtoint ptr [[P:%.*]] to i64
@@ -87,6 +108,59 @@ define i64 @test_ptrauth_resign_auth_mismatch(ptr %p) {
   ret i64 %authed
 }
 
+define i64 @test_ptrauth_nop_constant_mismatch() {
+; CHECK-LABEL: @test_ptrauth_nop_constant_mismatch(
+; CHECK-NEXT:    [[AUTHED:%.*]] = call i64 @llvm.ptrauth.auth(i64 ptrtoint (ptr ptrauth (ptr @foo, i32 1, i64 1234) to i64), i32 1, i64 12)
+; CHECK-NEXT:    ret i64 [[AUTHED]]
+;
+  %authed = call i64 @llvm.ptrauth.auth(i64 ptrtoint(ptr ptrauth(ptr @foo, i32 1, i64 1234) to i64), i32 1, i64 12)
+  ret i64 %authed
+}
+
+define i64 @test_ptrauth_nop_constant_mismatch_key() {
+; CHECK-LABEL: @test_ptrauth_nop_constant_mismatch_key(
+; CHECK-NEXT:    [[AUTHED:%.*]] = call i64 @llvm.ptrauth.auth(i64 ptrtoint (ptr ptrauth (ptr @foo, i32 1, i64 1234) to i64), i32 0, i64 1234)
+; CHECK-NEXT:    ret i64 [[AUTHED]]
+;
+  %authed = call i64 @llvm.ptrauth.auth(i64 ptrtoint(ptr ptrauth(ptr @foo, i32 1, i64 1234) to i64), i32 0, i64 1234)
+  ret i64 %authed
+}
+
+define i64 @test_ptrauth_nop_constant_addrdisc_mismatch() {
+; CHECK-LABEL: @test_ptrauth_nop_constant_addrdisc_mismatch(
+; CHECK-NEXT:    [[BLENDED:%.*]] = call i64 @llvm.ptrauth.blend(i64 ptrtoint (ptr @foo to i64), i64 12)
+; CHECK-NEXT:    [[AUTHED:%.*]] = call i64 @llvm.ptrauth.auth(i64 ptrtoint (ptr ptrauth (ptr @foo, i32 1, i64 1234, ptr @foo) to i64), i32 1, i64 [[BLENDED]])
+; CHECK-NEXT:    ret i64 [[AUTHED]]
+;
+  %addr = ptrtoint ptr @foo to i64
+  %blended = call i64 @llvm.ptrauth.blend(i64 %addr, i64 12)
+  %authed = call i64 @llvm.ptrauth.auth(i64 ptrtoint(ptr ptrauth(ptr @foo, i32 1, i64 1234, ptr @foo) to i64), i32 1, i64 %blended)
+  ret i64 %authed
+}
+
+define i64 @test_ptrauth_nop_constant_addrdisc_mismatch2() {
+; CHECK-LABEL: @test_ptrauth_nop_constant_addrdisc_mismatch2(
+; CHECK-NEXT:    [[BLENDED:%.*]] = call i64 @llvm.ptrauth.blend(i64 ptrtoint (ptr @bar to i64), i64 1234)
+; CHECK-NEXT:    [[AUTHED:%.*]] = call i64 @llvm.ptrauth.auth(i64 ptrtoint (ptr ptrauth (ptr @foo, i32 1, i64 1234, ptr @foo) to i64), i32 1, i64 [[BLENDED]])
+; CHECK-NEXT:    ret i64 [[AUTHED]]
+;
+  %addr = ptrtoint ptr @bar to i64
+  %blended = call i64 @llvm.ptrauth.blend(i64 %addr, i64 1234)
+  %authed = call i64 @llvm.ptrauth.auth(i64 ptrtoint(ptr ptrauth(ptr @foo, i32 1, i64 1234, ptr @foo) to i64), i32 1, i64 %blended)
+  ret i64 %authed
+}
+
+define i64 @test_ptrauth_resign_ptrauth_constant(ptr %p) {
+; CHECK-LABEL: @test_ptrauth_resign_ptrauth_constant(
+; CHECK-NEXT:    ret i64 ptrtoint (ptr ptrauth (ptr @foo, i32 0, i64 42) to i64)
+;
+
+  %tmp0 = ptrtoint ptr %p to i64
+  %authed = call i64 @llvm.ptrauth.resign(i64 ptrtoint(ptr ptrauth(ptr @foo, i32 1, i64 1234) to i64), i32 1, i64 1234, i32 0, i64 42)
+  ret i64 %authed
+}
+
 declare i64 @llvm.ptrauth.auth(i64, i32, i64)
 declare i64 @llvm.ptrauth.sign(i64, i32, i64)
 declare i64 @llvm.ptrauth.resign(i64, i32, i64, i32, i64)
+declare i64 @llvm.ptrauth.blend(i64, i64)