Index: lib/Transforms/Instrumentation/PGOInstrumentation.cpp
===================================================================
--- lib/Transforms/Instrumentation/PGOInstrumentation.cpp
+++ lib/Transforms/Instrumentation/PGOInstrumentation.cpp
@@ -1177,7 +1177,7 @@
   Builder.CreateCall(
       Intrinsic::getDeclaration(M, Intrinsic::instrprof_value_profile),
       {llvm::ConstantExpr::getBitCast(FuncNameVar, I8PtrTy),
-       Builder.getInt64(FuncHash), Builder.CreatePtrToInt(Length, Int64Ty),
+       Builder.getInt64(FuncHash), Builder.CreateZExtOrTrunc(Length, Int64Ty),
        Builder.getInt32(IPVK_MemOPSize), Builder.getInt32(CurCtrId)});
   ++CurCtrId;
 }
Index: test/Transforms/PGOProfile/memop_size_from_strlen.ll
===================================================================
--- /dev/null
+++ test/Transforms/PGOProfile/memop_size_from_strlen.ll
@@ -0,0 +1,14 @@
+; RUN: opt < %s -pgo-instr-gen -S | FileCheck %s
+
+declare void @llvm.memcpy.p0i8.p0i8.i32(i8* nocapture writeonly, i8* nocapture readonly, i32, i32, i1)
+declare i32 @strlen(i8* nocapture)
+
+; CHECK_LABEL: test
+; CHECK: %1 = zext i32 %c to i64
+; CHECK:  call void @llvm.instrprof.value.profile(i8* getelementptr inbounds ([4 x i8], [4 x i8]* @__profn_test, i32 0, i32 0), i64 12884901887, i64 %1, i32 1, i32 0)
+
+define void @test(i8* %a, i8* %p) {
+  %c = call i32 @strlen(i8* %p)
+  call void @llvm.memcpy.p0i8.p0i8.i32(i8* %a, i8* %p, i32 %c, i32 1, i1 false)
+  ret void
+}