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| author | Matthias Krüger <matthias.krueger@famsik.de> | 2024-07-18 18:10:16 +0200 |
|---|---|---|
| committer | GitHub <noreply@github.com> | 2024-07-18 18:10:16 +0200 |
| commit | 6f7fa03a0608c2eaaff2ad9c0afbb3414cd4b978 (patch) | |
| tree | 8e99c190675ef773768073568746ab26a2536ab7 /tests/codegen | |
| parent | ec6110f00c1eb6fe5f4ba68210989d4eed75cd74 (diff) | |
| parent | eb3cc5f824d74eb50ad1bdb3105045bd8eb135ef (diff) | |
| download | rust-6f7fa03a0608c2eaaff2ad9c0afbb3414cd4b978.tar.gz rust-6f7fa03a0608c2eaaff2ad9c0afbb3414cd4b978.zip | |
Rollup merge of #127748 - scottmcm:option_len, r=joboet
Use Option's discriminant as its size hint I was looking at this in MIR after a question on discord, and noticed that it ends up with a switch in MIR (<https://rust.godbolt.org/z/3q4cYnnb3>), which it doesn't need because (as `Option::as_slice` uses) the discriminant is already the length.
Diffstat (limited to 'tests/codegen')
| -rw-r--r-- | tests/codegen/option-as-slice.rs | 35 |
1 files changed, 34 insertions, 1 deletions
diff --git a/tests/codegen/option-as-slice.rs b/tests/codegen/option-as-slice.rs index 65637a2495d..cfa479aa4b2 100644 --- a/tests/codegen/option-as-slice.rs +++ b/tests/codegen/option-as-slice.rs @@ -14,6 +14,14 @@ pub fn u64_opt_as_slice(o: &Option<u64>) -> &[u64] { // CHECK-NOT: br // CHECK-NOT: switch // CHECK-NOT: icmp + // CHECK: %[[LEN:.+]] = load i64,{{.+}} !range ![[META_U64:.+]], !noundef + // CHECK-NOT: select + // CHECK-NOT: br + // CHECK-NOT: switch + // CHECK-NOT: icmp + // CHECK: %[[T0:.+]] = insertvalue { ptr, i64 } poison, ptr %{{.+}}, 0 + // CHECK-NEXT: %[[T1:.+]] = insertvalue { ptr, i64 } %[[T0]], i64 %[[LEN]], 1 + // CHECK-NEXT: ret { ptr, i64 } %[[T1]] o.as_slice() } @@ -25,10 +33,35 @@ pub fn nonzero_u64_opt_as_slice(o: &Option<NonZero<u64>>) -> &[NonZero<u64>] { // CHECK-NOT: switch // CHECK-NOT: icmp // CHECK: %[[NZ:.+]] = icmp ne i64 %{{.+}}, 0 - // CHECK-NEXT: zext i1 %[[NZ]] to i64 + // CHECK-NEXT: %[[LEN:.+]] = zext i1 %[[NZ]] to i64 // CHECK-NOT: select // CHECK-NOT: br // CHECK-NOT: switch // CHECK-NOT: icmp + // CHECK: %[[T0:.+]] = insertvalue { ptr, i64 } poison, ptr %o, 0 + // CHECK-NEXT: %[[T1:.+]] = insertvalue { ptr, i64 } %[[T0]], i64 %[[LEN]], 1 + // CHECK-NEXT: ret { ptr, i64 } %[[T1]] o.as_slice() } + +// CHECK-LABEL: @u8_opt_as_slice +#[no_mangle] +pub fn u8_opt_as_slice(o: &Option<u8>) -> &[u8] { + // CHECK-NOT: select + // CHECK-NOT: br + // CHECK-NOT: switch + // CHECK-NOT: icmp + // CHECK: %[[TAG:.+]] = load i8,{{.+}} !range ![[META_U8:.+]], !noundef + // CHECK: %[[LEN:.+]] = zext{{.*}} i8 %[[TAG]] to i64 + // CHECK-NOT: select + // CHECK-NOT: br + // CHECK-NOT: switch + // CHECK-NOT: icmp + // CHECK: %[[T0:.+]] = insertvalue { ptr, i64 } poison, ptr %{{.+}}, 0 + // CHECK-NEXT: %[[T1:.+]] = insertvalue { ptr, i64 } %[[T0]], i64 %[[LEN]], 1 + // CHECK-NEXT: ret { ptr, i64 } %[[T1]] + o.as_slice() +} + +// CHECK: ![[META_U64]] = !{i64 0, i64 2} +// CHECK: ![[META_U8]] = !{i8 0, i8 2} |