`assume` value ranges in `transmute`

Fixes #109958

3 files changed, 195 insertions, 11 deletions

diff --git a/tests/codegen/intrinsics/transmute-niched.rs b/tests/codegen/intrinsics/transmute-niched.rs
new file mode 100644
index 00000000000..69e9b1d1206
--- /dev/null
+++ b/tests/codegen/intrinsics/transmute-niched.rs
@@ -0,0 +1,184 @@
+// revisions: OPT DBG
+// [OPT] compile-flags: -C opt-level=3 -C no-prepopulate-passes
+// [DBG] compile-flags: -C opt-level=0 -C no-prepopulate-passes
+// only-64bit (so I don't need to worry about usize)
+// min-llvm-version: 15.0 # this test assumes `ptr`s
+
+#![crate_type = "lib"]
+
+use std::mem::transmute;
+use std::num::NonZeroU32;
+
+#[repr(u8)]
+pub enum SmallEnum {
+    A = 10,
+    B = 11,
+    C = 12,
+}
+
+// CHECK-LABEL: @check_to_enum(
+#[no_mangle]
+pub unsafe fn check_to_enum(x: i8) -> SmallEnum {
+    // OPT: %0 = icmp uge i8 %x, 10
+    // OPT: call void @llvm.assume(i1 %0)
+    // OPT: %1 = icmp ule i8 %x, 12
+    // OPT: call void @llvm.assume(i1 %1)
+    // DBG-NOT: icmp
+    // DBG-NOT: assume
+    // CHECK: ret i8 %x
+
+    transmute(x)
+}
+
+// CHECK-LABEL: @check_from_enum(
+#[no_mangle]
+pub unsafe fn check_from_enum(x: SmallEnum) -> i8 {
+    // OPT: %0 = icmp uge i8 %x, 10
+    // OPT: call void @llvm.assume(i1 %0)
+    // OPT: %1 = icmp ule i8 %x, 12
+    // OPT: call void @llvm.assume(i1 %1)
+    // DBG-NOT: icmp
+    // DBG-NOT: assume
+    // CHECK: ret i8 %x
+
+    transmute(x)
+}
+
+// CHECK-LABEL: @check_to_ordering(
+#[no_mangle]
+pub unsafe fn check_to_ordering(x: u8) -> std::cmp::Ordering {
+    // OPT: %0 = icmp uge i8 %x, -1
+    // OPT: %1 = icmp ule i8 %x, 1
+    // OPT: %2 = or i1 %0, %1
+    // OPT: call void @llvm.assume(i1 %2)
+    // DBG-NOT: icmp
+    // DBG-NOT: assume
+    // CHECK: ret i8 %x
+
+    transmute(x)
+}
+
+// CHECK-LABEL: @check_from_ordering(
+#[no_mangle]
+pub unsafe fn check_from_ordering(x: std::cmp::Ordering) -> u8 {
+    // OPT: %0 = icmp uge i8 %x, -1
+    // OPT: %1 = icmp ule i8 %x, 1
+    // OPT: %2 = or i1 %0, %1
+    // OPT: call void @llvm.assume(i1 %2)
+    // DBG-NOT: icmp
+    // DBG-NOT: assume
+    // CHECK: ret i8 %x
+
+    transmute(x)
+}
+
+#[repr(i32)]
+pub enum Minus100ToPlus100 {
+    A = -100,
+    B = -90,
+    C = -80,
+    D = -70,
+    E = -60,
+    F = -50,
+    G = -40,
+    H = -30,
+    I = -20,
+    J = -10,
+    K = 0,
+    L = 10,
+    M = 20,
+    N = 30,
+    O = 40,
+    P = 50,
+    Q = 60,
+    R = 70,
+    S = 80,
+    T = 90,
+    U = 100,
+}
+
+// CHECK-LABEL: @check_enum_from_char(
+#[no_mangle]
+pub unsafe fn check_enum_from_char(x: char) -> Minus100ToPlus100 {
+    // OPT: %0 = icmp ule i32 %x, 1114111
+    // OPT: call void @llvm.assume(i1 %0)
+    // OPT: %1 = icmp uge i32 %x, -100
+    // OPT: %2 = icmp ule i32 %x, 100
+    // OPT: %3 = or i1 %1, %2
+    // OPT: call void @llvm.assume(i1 %3)
+    // DBG-NOT: icmp
+    // DBG-NOT: assume
+    // CHECK: ret i32 %x
+
+    transmute(x)
+}
+
+// CHECK-LABEL: @check_enum_to_char(
+#[no_mangle]
+pub unsafe fn check_enum_to_char(x: Minus100ToPlus100) -> char {
+    // OPT: %0 = icmp uge i32 %x, -100
+    // OPT: %1 = icmp ule i32 %x, 100
+    // OPT: %2 = or i1 %0, %1
+    // OPT: call void @llvm.assume(i1 %2)
+    // OPT: %3 = icmp ule i32 %x, 1114111
+    // OPT: call void @llvm.assume(i1 %3)
+    // DBG-NOT: icmp
+    // DBG-NOT: assume
+    // CHECK: ret i32 %x
+
+    transmute(x)
+}
+
+// CHECK-LABEL: @check_swap_pair(
+#[no_mangle]
+pub unsafe fn check_swap_pair(x: (char, NonZeroU32)) -> (NonZeroU32, char) {
+    // OPT: %0 = icmp ule i32 %x.0, 1114111
+    // OPT: call void @llvm.assume(i1 %0)
+    // OPT: %1 = icmp uge i32 %x.0, 1
+    // OPT: call void @llvm.assume(i1 %1)
+    // OPT: %2 = icmp uge i32 %x.1, 1
+    // OPT: call void @llvm.assume(i1 %2)
+    // OPT: %3 = icmp ule i32 %x.1, 1114111
+    // OPT: call void @llvm.assume(i1 %3)
+    // DBG-NOT: icmp
+    // DBG-NOT: assume
+    // CHECK: %[[P1:.+]] = insertvalue { i32, i32 } poison, i32 %x.0, 0
+    // CHECK: %[[P2:.+]] = insertvalue { i32, i32 } %[[P1]], i32 %x.1, 1
+    // CHECK: ret { i32, i32 } %[[P2]]
+
+    transmute(x)
+}
+
+// CHECK-LABEL: @check_bool_from_ordering(
+#[no_mangle]
+pub unsafe fn check_bool_from_ordering(x: std::cmp::Ordering) -> bool {
+    // OPT: %0 = icmp uge i8 %x, -1
+    // OPT: %1 = icmp ule i8 %x, 1
+    // OPT: %2 = or i1 %0, %1
+    // OPT: call void @llvm.assume(i1 %2)
+    // OPT: %3 = icmp ule i8 %x, 1
+    // OPT: call void @llvm.assume(i1 %3)
+    // DBG-NOT: icmp
+    // DBG-NOT: assume
+    // CHECK: %[[R:.+]] = trunc i8 %x to i1
+    // CHECK: ret i1 %[[R]]
+
+    transmute(x)
+}
+
+// CHECK-LABEL: @check_bool_to_ordering(
+#[no_mangle]
+pub unsafe fn check_bool_to_ordering(x: bool) -> std::cmp::Ordering {
+    // CHECK: %0 = zext i1 %x to i8
+    // OPT: %1 = icmp ule i8 %0, 1
+    // OPT: call void @llvm.assume(i1 %1)
+    // OPT: %2 = icmp uge i8 %0, -1
+    // OPT: %3 = icmp ule i8 %0, 1
+    // OPT: %4 = or i1 %2, %3
+    // OPT: call void @llvm.assume(i1 %4)
+    // DBG-NOT: icmp
+    // DBG-NOT: assume
+    // CHECK: ret i8 %0
+
+    transmute(x)
+}
diff --git a/tests/codegen/intrinsics/transmute.rs b/tests/codegen/intrinsics/transmute.rs
index 57f901c6719..51c000b82ea 100644
--- a/tests/codegen/intrinsics/transmute.rs
+++ b/tests/codegen/intrinsics/transmute.rs
@@ -169,8 +169,8 @@ pub unsafe fn check_aggregate_from_bool(x: bool) -> Aggregate8 {
 #[no_mangle]
 pub unsafe fn check_byte_to_bool(x: u8) -> bool {
     // CHECK-NOT: alloca
-    // CHECK: %0 = trunc i8 %x to i1
-    // CHECK: ret i1 %0
+    // CHECK: %[[R:.+]] = trunc i8 %x to i1
+    // CHECK: ret i1 %[[R]]
     transmute(x)
 }
 
@@ -178,8 +178,8 @@ pub unsafe fn check_byte_to_bool(x: u8) -> bool {
 #[no_mangle]
 pub unsafe fn check_byte_from_bool(x: bool) -> u8 {
     // CHECK-NOT: alloca
-    // CHECK: %0 = zext i1 %x to i8
-    // CHECK: ret i8 %0
+    // CHECK: %[[R:.+]] = zext i1 %x to i8
+    // CHECK: ret i8 %[[R:.+]]
     transmute(x)
 }
 
diff --git a/tests/codegen/transmute-scalar.rs b/tests/codegen/transmute-scalar.rs
index af2cef472ec..a0894a505c7 100644
--- a/tests/codegen/transmute-scalar.rs
+++ b/tests/codegen/transmute-scalar.rs
@@ -1,4 +1,4 @@
-// compile-flags: -O -C no-prepopulate-passes
+// compile-flags: -C opt-level=0 -C no-prepopulate-passes
 // min-llvm-version: 15.0 # this test assumes `ptr`s and thus no `pointercast`s
 
 #![crate_type = "lib"]
@@ -10,7 +10,7 @@
 // However, `bitcast`s and `ptrtoint`s and `inttoptr`s are still worth doing when
 // that allows us to avoid the `alloca`s entirely; see `rvalue_creates_operand`.
 
-// CHECK-LABEL: define{{.*}}i32 @f32_to_bits(float noundef %x)
+// CHECK-LABEL: define{{.*}}i32 @f32_to_bits(float %x)
 // CHECK: %0 = bitcast float %x to i32
 // CHECK-NEXT: ret i32 %0
 #[no_mangle]
@@ -18,7 +18,7 @@ pub fn f32_to_bits(x: f32) -> u32 {
     unsafe { std::mem::transmute(x) }
 }
 
-// CHECK-LABEL: define{{.*}}i8 @bool_to_byte(i1 noundef zeroext %b)
+// CHECK-LABEL: define{{.*}}i8 @bool_to_byte(i1 zeroext %b)
 // CHECK: %0 = zext i1 %b to i8
 // CHECK-NEXT: ret i8 %0
 #[no_mangle]
@@ -26,7 +26,7 @@ pub fn bool_to_byte(b: bool) -> u8 {
     unsafe { std::mem::transmute(b) }
 }
 
-// CHECK-LABEL: define{{.*}}noundef zeroext i1 @byte_to_bool(i8 noundef %byte)
+// CHECK-LABEL: define{{.*}}zeroext i1 @byte_to_bool(i8 %byte)
 // CHECK: %0 = trunc i8 %byte to i1
 // CHECK-NEXT: ret i1 %0
 #[no_mangle]
@@ -34,14 +34,14 @@ pub unsafe fn byte_to_bool(byte: u8) -> bool {
     std::mem::transmute(byte)
 }
 
-// CHECK-LABEL: define{{.*}}ptr @ptr_to_ptr(ptr noundef %p)
+// CHECK-LABEL: define{{.*}}ptr @ptr_to_ptr(ptr %p)
 // CHECK: ret ptr %p
 #[no_mangle]
 pub fn ptr_to_ptr(p: *mut u16) -> *mut u8 {
     unsafe { std::mem::transmute(p) }
 }
 
-// CHECK: define{{.*}}[[USIZE:i[0-9]+]] @ptr_to_int(ptr noundef %p)
+// CHECK: define{{.*}}[[USIZE:i[0-9]+]] @ptr_to_int(ptr %p)
 // CHECK: %0 = ptrtoint ptr %p to [[USIZE]]
 // CHECK-NEXT: ret [[USIZE]] %0
 #[no_mangle]
@@ -49,7 +49,7 @@ pub fn ptr_to_int(p: *mut u16) -> usize {
     unsafe { std::mem::transmute(p) }
 }
 
-// CHECK: define{{.*}}ptr @int_to_ptr([[USIZE]] noundef %i)
+// CHECK: define{{.*}}ptr @int_to_ptr([[USIZE]] %i)
 // CHECK: %0 = inttoptr [[USIZE]] %i to ptr
 // CHECK-NEXT: ret ptr %0
 #[no_mangle]