apply noundef explicitly in all cases instead of relying on dereferenceable implying it

Author: erikdesjardins

Diff for: compiler/rustc_codegen_llvm/src/abi.rs

@@ -69,9 +69,7 @@ impl ArgAttributesExt for ArgAttributes {
                 } else {
                     llvm::LLVMRustAddDereferenceableOrNullAttr(llfn, idx.as_uint(), deref);
                 }
-                // dereferenceable implies nonnull noundef; dereferenceable_or_null implies noundef
                 regular -= ArgAttribute::NonNull;
-                regular -= ArgAttribute::NoUndef;
             }
             if let Some(align) = self.pointee_align {
                 llvm::LLVMRustAddAlignmentAttr(llfn, idx.as_uint(), align.bytes() as u32);
@@ -111,9 +109,7 @@ impl ArgAttributesExt for ArgAttributes {
                         deref,
                     );
                 }
-                // dereferenceable implies nonnull noundef; dereferenceable_or_null implies noundef
                 regular -= ArgAttribute::NonNull;
-                regular -= ArgAttribute::NoUndef;
             }
             if let Some(align) = self.pointee_align {
                 llvm::LLVMRustAddAlignmentCallSiteAttr(

Diff for: src/test/codegen/function-arguments.rs

@@ -25,48 +25,48 @@ pub fn maybeuninit_boolean(x: MaybeUninit<bool>) -> MaybeUninit<bool> {
   x
 }
 
-// CHECK: @readonly_borrow(i32* noalias readonly align 4 dereferenceable(4) %_1)
+// CHECK: @readonly_borrow(i32* noalias noundef readonly align 4 dereferenceable(4) %_1)
 // FIXME #25759 This should also have `nocapture`
 #[no_mangle]
 pub fn readonly_borrow(_: &i32) {
 }
 
-// CHECK: @static_borrow(i32* noalias readonly align 4 dereferenceable(4) %_1)
+// CHECK: @static_borrow(i32* noalias noundef readonly align 4 dereferenceable(4) %_1)
 // static borrow may be captured
 #[no_mangle]
 pub fn static_borrow(_: &'static i32) {
 }
 
-// CHECK: @named_borrow(i32* noalias readonly align 4 dereferenceable(4) %_1)
+// CHECK: @named_borrow(i32* noalias noundef readonly align 4 dereferenceable(4) %_1)
 // borrow with named lifetime may be captured
 #[no_mangle]
 pub fn named_borrow<'r>(_: &'r i32) {
 }
 
-// CHECK: @unsafe_borrow(i16* align 2 dereferenceable(2) %_1)
+// CHECK: @unsafe_borrow(i16* noundef align 2 dereferenceable(2) %_1)
 // unsafe interior means this isn't actually readonly and there may be aliases ...
 #[no_mangle]
 pub fn unsafe_borrow(_: &UnsafeInner) {
 }
 
-// CHECK: @mutable_unsafe_borrow(i16* noalias align 2 dereferenceable(2) %_1)
+// CHECK: @mutable_unsafe_borrow(i16* noalias noundef align 2 dereferenceable(2) %_1)
 // ... unless this is a mutable borrow, those never alias
 #[no_mangle]
 pub fn mutable_unsafe_borrow(_: &mut UnsafeInner) {
 }
 
-// CHECK: @mutable_borrow(i32* noalias align 4 dereferenceable(4) %_1)
+// CHECK: @mutable_borrow(i32* noalias noundef align 4 dereferenceable(4) %_1)
 // FIXME #25759 This should also have `nocapture`
 #[no_mangle]
 pub fn mutable_borrow(_: &mut i32) {
 }
 
-// CHECK: @indirect_struct(%S* noalias nocapture dereferenceable(32) %_1)
+// CHECK: @indirect_struct(%S* noalias nocapture noundef dereferenceable(32) %_1)
 #[no_mangle]
 pub fn indirect_struct(_: S) {
 }
 
-// CHECK: @borrowed_struct(%S* noalias readonly align 4 dereferenceable(32) %_1)
+// CHECK: @borrowed_struct(%S* noalias noundef readonly align 4 dereferenceable(32) %_1)
 // FIXME #25759 This should also have `nocapture`
 #[no_mangle]
 pub fn borrowed_struct(_: &S) {
@@ -85,7 +85,7 @@ pub fn _box(x: Box<i32>) -> Box<i32> {
   x
 }
 
-// CHECK: @struct_return(%S* noalias nocapture sret(%S) dereferenceable(32){{( %0)?}})
+// CHECK: @struct_return(%S* noalias nocapture noundef sret(%S) dereferenceable(32){{( %0)?}})
 #[no_mangle]
 pub fn struct_return() -> S {
   S {
@@ -128,18 +128,18 @@ pub fn raw_slice(_: *const [u8]) {
 pub fn str(_: &[u8]) {
 }
 
-// CHECK: @trait_borrow({}* noundef nonnull align 1 %_1.0, [3 x [[USIZE]]]* noalias readonly align {{.*}} dereferenceable({{.*}}) %_1.1)
+// CHECK: @trait_borrow({}* noundef nonnull align 1 %_1.0, [3 x [[USIZE]]]* noalias noundef readonly align {{.*}} dereferenceable({{.*}}) %_1.1)
 // FIXME #25759 This should also have `nocapture`
 #[no_mangle]
 pub fn trait_borrow(_: &Drop) {
 }
 
-// CHECK: @trait_raw({}* %_1.0, [3 x [[USIZE]]]* noalias readonly align {{.*}} dereferenceable({{.*}}) %_1.1)
+// CHECK: @trait_raw({}* %_1.0, [3 x [[USIZE]]]* noalias noundef readonly align {{.*}} dereferenceable({{.*}}) %_1.1)
 #[no_mangle]
 pub fn trait_raw(_: *const Drop) {
 }
 
-// CHECK: @trait_box({}* noalias noundef nonnull align 1{{( %0)?}}, [3 x [[USIZE]]]* noalias readonly align {{.*}} dereferenceable({{.*}}){{( %1)?}})
+// CHECK: @trait_box({}* noalias noundef nonnull align 1{{( %0)?}}, [3 x [[USIZE]]]* noalias noundef readonly align {{.*}} dereferenceable({{.*}}){{( %1)?}})
 #[no_mangle]
 pub fn trait_box(_: Box<Drop>) {
 }

Diff for: src/test/codegen/packed.rs

@@ -52,7 +52,7 @@ pub struct BigPacked2 {
 #[no_mangle]
 pub fn call_pkd1(f: fn() -> Array) -> BigPacked1 {
 // CHECK: [[ALLOCA:%[_a-z0-9]+]] = alloca %Array
-// CHECK: call void %{{.*}}(%Array* noalias nocapture sret{{.*}} dereferenceable(32) [[ALLOCA]])
+// CHECK: call void %{{.*}}(%Array* noalias nocapture noundef sret{{.*}} dereferenceable(32) [[ALLOCA]])
 // CHECK: call void @llvm.memcpy.{{.*}}(i8* align 1 %{{.*}}, i8* align 4 %{{.*}}, i{{[0-9]+}} 32, i1 false)
     // check that calls whose destination is a field of a packed struct
     // go through an alloca rather than calling the function with an
@@ -64,7 +64,7 @@ pub fn call_pkd1(f: fn() -> Array) -> BigPacked1 {
 #[no_mangle]
 pub fn call_pkd2(f: fn() -> Array) -> BigPacked2 {
 // CHECK: [[ALLOCA:%[_a-z0-9]+]] = alloca %Array
-// CHECK: call void %{{.*}}(%Array* noalias nocapture sret{{.*}} dereferenceable(32) [[ALLOCA]])
+// CHECK: call void %{{.*}}(%Array* noalias nocapture noundef sret{{.*}} dereferenceable(32) [[ALLOCA]])
 // CHECK: call void @llvm.memcpy.{{.*}}(i8* align 2 %{{.*}}, i8* align 4 %{{.*}}, i{{[0-9]+}} 32, i1 false)
     // check that calls whose destination is a field of a packed struct
     // go through an alloca rather than calling the function with an