45 lines
1.5 KiB
Rust
45 lines
1.5 KiB
Rust
// no-system-llvm
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// compile-flags: -O
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// ignore-debug: the debug assertions get in the way
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#![crate_type = "lib"]
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// Make sure no bounds checks are emitted in the loop when upfront slicing
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// ensures that the slices are big enough.
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// In particular, bounds checks were not always optimized out if the upfront
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// check was for a greater len than the loop requires.
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// (i.e. `already_sliced_no_bounds_check` was not always optimized even when
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// `already_sliced_no_bounds_check_exact` was)
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// CHECK-LABEL: @already_sliced_no_bounds_check
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#[no_mangle]
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pub fn already_sliced_no_bounds_check(a: &[u8], b: &[u8], c: &mut [u8]) {
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// CHECK: slice_end_index_len_fail
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// CHECK-NOT: panic_bounds_check
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let _ = (&a[..2048], &b[..2048], &mut c[..2048]);
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for i in 0..1024 {
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c[i] = a[i] ^ b[i];
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}
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}
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// CHECK-LABEL: @already_sliced_no_bounds_check_exact
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#[no_mangle]
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pub fn already_sliced_no_bounds_check_exact(a: &[u8], b: &[u8], c: &mut [u8]) {
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// CHECK: slice_end_index_len_fail
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// CHECK-NOT: panic_bounds_check
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let _ = (&a[..1024], &b[..1024], &mut c[..1024]);
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for i in 0..1024 {
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c[i] = a[i] ^ b[i];
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}
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}
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// Make sure we're checking for the right thing: there can be a panic if the slice is too small.
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// CHECK-LABEL: @already_sliced_bounds_check
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#[no_mangle]
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pub fn already_sliced_bounds_check(a: &[u8], b: &[u8], c: &mut [u8]) {
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// CHECK: slice_end_index_len_fail
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// CHECK: panic_bounds_check
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let _ = (&a[..1023], &b[..2048], &mut c[..2048]);
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for i in 0..1024 {
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c[i] = a[i] ^ b[i];
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}
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}
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