diff --git a/llvm/lib/Transforms/Utils/BuildLibCalls.cpp b/llvm/lib/Transforms/Utils/BuildLibCalls.cpp
--- a/llvm/lib/Transforms/Utils/BuildLibCalls.cpp
+++ b/llvm/lib/Transforms/Utils/BuildLibCalls.cpp
@@ -478,6 +478,8 @@
   case LibFunc_modfl:
     Changed |= setDoesNotThrow(F);
     Changed |= setWillReturn(F);
+    Changed |= setOnlyAccessesArgMemory(F);
+    Changed |= setOnlyWritesMemory(F);
     Changed |= setDoesNotCapture(F, 1);
     break;
   case LibFunc_memcpy:
@@ -725,6 +727,8 @@
   case LibFunc_frexpl:
     Changed |= setDoesNotThrow(F);
     Changed |= setWillReturn(F);
+    Changed |= setOnlyAccessesArgMemory(F);
+    Changed |= setOnlyWritesMemory(F);
     Changed |= setDoesNotCapture(F, 1);
     break;
   case LibFunc_fstatvfs:
diff --git a/llvm/test/Transforms/InferFunctionAttrs/annotate.ll b/llvm/test/Transforms/InferFunctionAttrs/annotate.ll
--- a/llvm/test/Transforms/InferFunctionAttrs/annotate.ll
+++ b/llvm/test/Transforms/InferFunctionAttrs/annotate.ll
@@ -503,13 +503,13 @@
 ; CHECK-AIX: declare void @vec_free(ptr allocptr nocapture noundef) [[INACCESSIBLEMEMORARGMEMONLY_NOUNWIND_WILLRETURN_FAMILY_VEC_MALLOC:#[0-9]+]]
 declare void @vec_free(ptr)
 
-; CHECK: declare double @frexp(double, ptr nocapture) [[NOFREE_NOUNWIND_WILLRETURN:#[0-9]+]]
+; CHECK: declare double @frexp(double, ptr nocapture) [[ARGMEMONLY_NOFREE_NOUNWIND_WILLRETURN_WRITEONLY:#[0-9]+]]
 declare double @frexp(double, ptr)
 
-; CHECK: declare float @frexpf(float, ptr nocapture) [[NOFREE_NOUNWIND_WILLRETURN]]
+; CHECK: declare float @frexpf(float, ptr nocapture) [[ARGMEMONLY_NOFREE_NOUNWIND_WILLRETURN_WRITEONLY]]
 declare float @frexpf(float, ptr)
 
-; CHECK: declare x86_fp80 @frexpl(x86_fp80, ptr nocapture) [[NOFREE_NOUNWIND_WILLRETURN]]
+; CHECK: declare x86_fp80 @frexpl(x86_fp80, ptr nocapture) [[ARGMEMONLY_NOFREE_NOUNWIND_WILLRETURN_WRITEONLY]]
 declare x86_fp80 @frexpl(x86_fp80, ptr)
 
 ; CHECK: declare noundef i32 @fscanf(ptr nocapture noundef, ptr nocapture noundef readonly, ...) [[NOFREE_NOUNWIND]]
@@ -705,16 +705,16 @@
 ; CHECK: declare noundef i32 @mkdir(ptr nocapture noundef readonly, i16 noundef zeroext) [[NOFREE_NOUNWIND]]
 declare i32 @mkdir(ptr, i16 zeroext)
 
-; CHECK: declare noundef i64 @mktime(ptr nocapture noundef) [[NOFREE_NOUNWIND_WILLRETURN]]
+; CHECK: declare noundef i64 @mktime(ptr nocapture noundef) [[NOFREE_NOUNWIND_WILLRETURN:#[0-9]+]]
 declare i64 @mktime(ptr)
 
-; CHECK: declare double @modf(double, ptr nocapture) [[NOFREE_NOUNWIND_WILLRETURN]]
+; CHECK: declare double @modf(double, ptr nocapture) [[ARGMEMONLY_NOFREE_NOUNWIND_WILLRETURN_WRITEONLY]]
 declare double @modf(double, ptr)
 
-; CHECK: declare float @modff(float, ptr nocapture) [[NOFREE_NOUNWIND_WILLRETURN]]
+; CHECK: declare float @modff(float, ptr nocapture) [[ARGMEMONLY_NOFREE_NOUNWIND_WILLRETURN_WRITEONLY]]
 declare float @modff(float, ptr)
 
-; CHECK: declare x86_fp80 @modfl(x86_fp80, ptr nocapture) [[NOFREE_NOUNWIND_WILLRETURN]]
+; CHECK: declare x86_fp80 @modfl(x86_fp80, ptr nocapture) [[ARGMEMONLY_NOFREE_NOUNWIND_WILLRETURN_WRITEONLY]]
 declare x86_fp80 @modfl(x86_fp80, ptr)
 
 ; CHECK: declare double @nearbyint(double) [[NOFREE_NOUNWIND_WILLRETURN_WRITEONLY]]
@@ -1081,6 +1081,7 @@
 
 ; CHECK-DAG: attributes [[NOFREE_NOUNWIND_WILLRETURN]] = { mustprogress nofree nounwind willreturn }
 ; CHECK-DAG: attributes [[NOFREE_NOUNWIND_WILLRETURN_WRITEONLY]] = { mustprogress nofree nounwind willreturn memory(write) }
+; CHECK-DAG: attributes [[ARGMEMONLY_NOFREE_NOUNWIND_WILLRETURN_WRITEONLY]] = { mustprogress nofree nounwind willreturn memory(argmem: write) }
 ; CHECK-DAG: attributes [[NOFREE_NOUNWIND]] = { nofree nounwind }
 ; CHECK-DAG: attributes [[INACCESSIBLEMEMONLY_NOFREE_NOUNWIND_WILLRETURN_ALLOCKIND_ALLOCUNINIT_ALLOCSIZE1_FAMILY_MALLOC]] = { mustprogress nofree nounwind willreturn allockind("alloc,uninitialized,aligned") allocsize(1) memory(inaccessiblemem: readwrite) "alloc-family"="malloc" }
 ; CHECK-DAG: attributes [[INACCESSIBLEMEMONLY_NOFREE_NOUNWIND_WILLRETURN_ALLOCKIND_ALLOCZEROED_ALLOCSIZE01_FAMILY_MALLOC]] = { mustprogress nofree nounwind willreturn allockind("alloc,zeroed") allocsize(0,1) memory(inaccessiblemem: readwrite) "alloc-family"="malloc" }