diff --git a/library/core/src/num/nonzero.rs b/library/core/src/num/nonzero.rs index f5ecf501ce990..489eb99f46b49 100644 --- a/library/core/src/num/nonzero.rs +++ b/library/core/src/num/nonzero.rs @@ -104,7 +104,22 @@ macro_rules! nonzero_integers { #[inline] #[rustc_const_stable(feature = "const_nonzero_get", since = "1.34.0")] pub const fn get(self) -> $Int { - self.0 + // FIXME: Remove this after LLVM supports `!range` metadata for function + // arguments https://github.com/llvm/llvm-project/issues/76628 + // + // Rustc can set range metadata only if it loads `self` from + // memory somewhere. If the value of `self` was from by-value argument + // of some not-inlined function, LLVM don't have range metadata + // to understand that the value cannot be zero. + if self.0 == 0 { + // SAFETY: It is an invariant of this type. + unsafe { + crate::hint::unreachable_unchecked() + } + } + else { + self.0 + } } } diff --git a/tests/codegen/issues/issue-119422.rs b/tests/codegen/issues/issue-119422.rs new file mode 100644 index 0000000000000..6e97b85758f08 --- /dev/null +++ b/tests/codegen/issues/issue-119422.rs @@ -0,0 +1,73 @@ +//! This test checks that compiler don't generate useless compares to zeros +//! for NonZero integer types. + +// compile-flags: -O --edition=2021 -Zmerge-functions=disabled +// only-64bit (because the LLVM type of i64 for usize shows up) + +#![crate_type = "lib"] + +use core::num::*; +use core::ptr::NonNull; + +// CHECK-LABEL: @check_non_null +#[no_mangle] +pub fn check_non_null(x: NonNull) -> bool { + // CHECK: ret i1 false + x.as_ptr().is_null() +} + +// CHECK-LABEL: @equals_zero_is_false_u8 +#[no_mangle] +pub fn equals_zero_is_false_u8(x: NonZeroU8) -> bool { + // CHECK-NOT: br + // CHECK: ret i1 false + // CHECK-NOT: br + x.get() == 0 +} + +// CHECK-LABEL: @not_equals_zero_is_true_u8 +#[no_mangle] +pub fn not_equals_zero_is_true_u8(x: NonZeroU8) -> bool { + // CHECK-NOT: br + // CHECK: ret i1 true + // CHECK-NOT: br + x.get() != 0 +} + +// CHECK-LABEL: @equals_zero_is_false_i8 +#[no_mangle] +pub fn equals_zero_is_false_i8(x: NonZeroI8) -> bool { + // CHECK-NOT: br + // CHECK: ret i1 false + // CHECK-NOT: br + x.get() == 0 +} + +// CHECK-LABEL: @not_equals_zero_is_true_i8 +#[no_mangle] +pub fn not_equals_zero_is_true_i8(x: NonZeroI8) -> bool { + // CHECK-NOT: br + // CHECK: ret i1 true + // CHECK-NOT: br + x.get() != 0 +} + +// CHECK-LABEL: @usize_try_from_u32 +#[no_mangle] +pub fn usize_try_from_u32(x: NonZeroU32) -> NonZeroUsize { + // CHECK-NOT: br + // CHECK: zext i32 %{{.*}} to i64 + // CHECK-NOT: br + // CHECK: ret i64 + x.try_into().unwrap() +} + +// CHECK-LABEL: @isize_try_from_i32 +#[no_mangle] +pub fn isize_try_from_i32(x: NonZeroI32) -> NonZeroIsize { + // CHECK-NOT: br + // CHECK: sext i32 %{{.*}} to i64 + // CHECK-NOT: br + // CHECK: ret i64 + x.try_into().unwrap() +}