Auto merge of #121668 - erikdesjardins:commonprim, r=scottmcm,oli-obk

Represent `Result<usize, Box<T>>` as ScalarPair(i64, ptr)

This allows types like `Result<usize, std::io::Error>` (and integers of differing sign, e.g. `Result<u64, i64>`) to be passed in a pair of registers instead of through memory, like `Result<u64, u64>` or `Result<Box<T>, Box<U>>` are today.

Fixes #97540.

r? `@ghost`

2 files changed, 143 insertions, 12 deletions

diff --git a/tests/codegen/common_prim_int_ptr.rs b/tests/codegen/common_prim_int_ptr.rs
new file mode 100644
index 00000000000..87fa89abb86
--- /dev/null
+++ b/tests/codegen/common_prim_int_ptr.rs
@@ -0,0 +1,51 @@
+//@ compile-flags: -O
+
+#![crate_type = "lib"]
+#![feature(core_intrinsics)]
+
+// Tests that codegen works properly when enums like `Result<usize, Box<()>>`
+// are represented as `{ u64, ptr }`, i.e., for `Ok(123)`, `123` is stored
+// as a pointer.
+
+// CHECK-LABEL: @insert_int
+#[no_mangle]
+pub fn insert_int(x: usize) -> Result<usize, Box<()>> {
+    // CHECK: start:
+    // CHECK-NEXT: inttoptr i{{[0-9]+}} %x to ptr
+    // CHECK-NEXT: insertvalue
+    // CHECK-NEXT: ret { i{{[0-9]+}}, ptr }
+    Ok(x)
+}
+
+// CHECK-LABEL: @insert_box
+#[no_mangle]
+pub fn insert_box(x: Box<()>) -> Result<usize, Box<()>> {
+    // CHECK: start:
+    // CHECK-NEXT: insertvalue { i{{[0-9]+}}, ptr }
+    // CHECK-NEXT: ret
+    Err(x)
+}
+
+// CHECK-LABEL: @extract_int
+// CHECK-NOT: nonnull
+// CHECK-SAME: (i{{[0-9]+}} {{[^,]+}} [[DISCRIMINANT:%[0-9]+]], ptr {{[^,]+}} [[PAYLOAD:%[0-9]+]])
+#[no_mangle]
+pub unsafe fn extract_int(x: Result<usize, Box<()>>) -> usize {
+    // CHECK: [[TEMP:%.+]] = ptrtoint ptr [[PAYLOAD]] to [[USIZE:i[0-9]+]]
+    // CHECK: ret [[USIZE]] [[TEMP]]
+    match x {
+        Ok(v) => v,
+        Err(_) => std::intrinsics::unreachable(),
+    }
+}
+
+// CHECK-LABEL: @extract_box
+// CHECK-SAME: (i{{[0-9]+}} {{[^,]+}} [[DISCRIMINANT:%[0-9]+]], ptr {{[^,]+}} [[PAYLOAD:%[0-9]+]])
+#[no_mangle]
+pub unsafe fn extract_box(x: Result<usize, Box<i32>>) -> Box<i32> {
+    // CHECK: ret ptr [[PAYLOAD]]
+    match x {
+        Ok(_) => std::intrinsics::unreachable(),
+        Err(e) => e,
+    }
+}
diff --git a/tests/codegen/try_question_mark_nop.rs b/tests/codegen/try_question_mark_nop.rs
index 58cd6ff233a..f6cdf955209 100644
--- a/tests/codegen/try_question_mark_nop.rs
+++ b/tests/codegen/try_question_mark_nop.rs
@@ -4,17 +4,41 @@
 #![crate_type = "lib"]
 #![feature(try_blocks)]
 
-// These are now NOPs in LLVM 15, presumably thanks to nikic's change mentioned in
-// <https://github.com/rust-lang/rust/issues/85133#issuecomment-1072168354>.
-// Unfortunately, as of 2022-08-17 they're not yet nops for `u64`s nor `Option`.
-
 use std::ops::ControlFlow::{self, Continue, Break};
+use std::ptr::NonNull;
+
+// CHECK-LABEL: @option_nop_match_32
+#[no_mangle]
+pub fn option_nop_match_32(x: Option<u32>) -> Option<u32> {
+    // CHECK: start:
+    // CHECK-NEXT: insertvalue { i32, i32 }
+    // CHECK-NEXT: insertvalue { i32, i32 }
+    // CHECK-NEXT: ret { i32, i32 }
+    match x {
+        Some(x) => Some(x),
+        None => None,
+    }
+}
+
+// CHECK-LABEL: @option_nop_traits_32
+#[no_mangle]
+pub fn option_nop_traits_32(x: Option<u32>) -> Option<u32> {
+    // CHECK: start:
+    // CHECK-NEXT: insertvalue { i32, i32 }
+    // CHECK-NEXT: insertvalue { i32, i32 }
+    // CHECK-NEXT: ret { i32, i32 }
+    try {
+        x?
+    }
+}
 
 // CHECK-LABEL: @result_nop_match_32
 #[no_mangle]
 pub fn result_nop_match_32(x: Result<i32, u32>) -> Result<i32, u32> {
-    // CHECK: start
-    // CHECK-NEXT: ret i64 %0
+    // CHECK: start:
+    // CHECK-NEXT: insertvalue { i32, i32 }
+    // CHECK-NEXT: insertvalue { i32, i32 }
+    // CHECK-NEXT: ret { i32, i32 }
     match x {
         Ok(x) => Ok(x),
         Err(x) => Err(x),
@@ -24,8 +48,60 @@ pub fn result_nop_match_32(x: Result<i32, u32>) -> Result<i32, u32> {
 // CHECK-LABEL: @result_nop_traits_32
 #[no_mangle]
 pub fn result_nop_traits_32(x: Result<i32, u32>) -> Result<i32, u32> {
-    // CHECK: start
-    // CHECK-NEXT: ret i64 %0
+    // CHECK: start:
+    // CHECK-NEXT: insertvalue { i32, i32 }
+    // CHECK-NEXT: insertvalue { i32, i32 }
+    // CHECK-NEXT: ret { i32, i32 }
+    try {
+        x?
+    }
+}
+
+// CHECK-LABEL: @result_nop_match_64
+#[no_mangle]
+pub fn result_nop_match_64(x: Result<i64, u64>) -> Result<i64, u64> {
+    // CHECK: start:
+    // CHECK-NEXT: insertvalue { i64, i64 }
+    // CHECK-NEXT: insertvalue { i64, i64 }
+    // CHECK-NEXT: ret { i64, i64 }
+    match x {
+        Ok(x) => Ok(x),
+        Err(x) => Err(x),
+    }
+}
+
+// CHECK-LABEL: @result_nop_traits_64
+#[no_mangle]
+pub fn result_nop_traits_64(x: Result<i64, u64>) -> Result<i64, u64> {
+    // CHECK: start:
+    // CHECK-NEXT: insertvalue { i64, i64 }
+    // CHECK-NEXT: insertvalue { i64, i64 }
+    // CHECK-NEXT: ret { i64, i64 }
+    try {
+        x?
+    }
+}
+
+// CHECK-LABEL: @result_nop_match_ptr
+#[no_mangle]
+pub fn result_nop_match_ptr(x: Result<usize, Box<()>>) -> Result<usize, Box<()>> {
+    // CHECK: start:
+    // CHECK-NEXT: insertvalue { i{{[0-9]+}}, ptr }
+    // CHECK-NEXT: insertvalue { i{{[0-9]+}}, ptr }
+    // CHECK-NEXT: ret
+    match x {
+        Ok(x) => Ok(x),
+        Err(x) => Err(x),
+    }
+}
+
+// CHECK-LABEL: @result_nop_traits_ptr
+#[no_mangle]
+pub fn result_nop_traits_ptr(x: Result<u64, NonNull<()>>) -> Result<u64, NonNull<()>> {
+    // CHECK: start:
+    // CHECK-NEXT: insertvalue { i{{[0-9]+}}, ptr }
+    // CHECK-NEXT: insertvalue { i{{[0-9]+}}, ptr }
+    // CHECK-NEXT: ret
     try {
         x?
     }
@@ -34,8 +110,10 @@ pub fn result_nop_traits_32(x: Result<i32, u32>) -> Result<i32, u32> {
 // CHECK-LABEL: @control_flow_nop_match_32
 #[no_mangle]
 pub fn control_flow_nop_match_32(x: ControlFlow<i32, u32>) -> ControlFlow<i32, u32> {
-    // CHECK: start
-    // CHECK-NEXT: ret i64 %0
+    // CHECK: start:
+    // CHECK-NEXT: insertvalue { i32, i32 }
+    // CHECK-NEXT: insertvalue { i32, i32 }
+    // CHECK-NEXT: ret { i32, i32 }
     match x {
         Continue(x) => Continue(x),
         Break(x) => Break(x),
@@ -45,8 +123,10 @@ pub fn control_flow_nop_match_32(x: ControlFlow<i32, u32>) -> ControlFlow<i32, u
 // CHECK-LABEL: @control_flow_nop_traits_32
 #[no_mangle]
 pub fn control_flow_nop_traits_32(x: ControlFlow<i32, u32>) -> ControlFlow<i32, u32> {
-    // CHECK: start
-    // CHECK-NEXT: ret i64 %0
+    // CHECK: start:
+    // CHECK-NEXT: insertvalue { i32, i32 }
+    // CHECK-NEXT: insertvalue { i32, i32 }
+    // CHECK-NEXT: ret { i32, i32 }
     try {
         x?
     }