a32305a80f
This way it's one check instead of two, so hopefully it'll be better Nightly: ``` layout_array_i32: movq %rdi, %rax movl $4, %ecx mulq %rcx jo .LBB1_2 movabsq $9223372036854775805, %rcx cmpq %rcx, %rax jae .LBB1_2 movl $4, %edx retq .LBB1_2: … ``` This PR: ``` movq %rcx, %rax shrq $61, %rax jne .LBB2_1 shlq $2, %rcx movl $4, %edx movq %rcx, %rax retq .LBB2_1: … ```
31 lines
884 B
Rust
31 lines
884 B
Rust
// compile-flags: -O
|
|
// only-x86_64
|
|
// ignore-debug: the debug assertions get in the way
|
|
|
|
#![crate_type = "lib"]
|
|
|
|
use std::alloc::Layout;
|
|
|
|
type RGB48 = [u16; 3];
|
|
|
|
// CHECK-LABEL: @layout_array_rgb48
|
|
#[no_mangle]
|
|
pub fn layout_array_rgb48(n: usize) -> Layout {
|
|
// CHECK-NOT: llvm.umul.with.overflow.i64
|
|
// CHECK: icmp ugt i64 %n, 1537228672809129301
|
|
// CHECK-NOT: llvm.umul.with.overflow.i64
|
|
// CHECK: mul nuw nsw i64 %n, 6
|
|
// CHECK-NOT: llvm.umul.with.overflow.i64
|
|
Layout::array::<RGB48>(n).unwrap()
|
|
}
|
|
|
|
// CHECK-LABEL: @layout_array_i32
|
|
#[no_mangle]
|
|
pub fn layout_array_i32(n: usize) -> Layout {
|
|
// CHECK-NOT: llvm.umul.with.overflow.i64
|
|
// CHECK: icmp ugt i64 %n, 2305843009213693951
|
|
// CHECK-NOT: llvm.umul.with.overflow.i64
|
|
// CHECK: shl nuw nsw i64 %n, 2
|
|
// CHECK-NOT: llvm.umul.with.overflow.i64
|
|
Layout::array::<i32>(n).unwrap()
|
|
}
|