Files
rust/tests/codegen-llvm
Stuart Cook 8b036c7b72 Rollup merge of #152486 - fneddy:s390x_simplify_backchain, r=dingxiangfei2009
remove redundant backchain attribute in codegen

llvm will look at both
1. the values of `"target-features"` and
2. the function string attributes.

this patch removes the redundant function string attribute because it is not needed at all. rustc sets the `+backchain` attribute through `target_features_attr(...)`
https://github.com/rust-lang/rust/blob/d34f1f931489618efffc4007e6b6bdb9e10f6467/compiler/rustc_codegen_llvm/src/attributes.rs#L590
https://github.com/rust-lang/rust/blob/d34f1f931489618efffc4007e6b6bdb9e10f6467/compiler/rustc_codegen_llvm/src/attributes.rs#L326-L337
2026-02-13 15:19:13 +11:00
..
2025-11-08 10:57:35 -07:00
2026-01-26 13:43:06 -06:00
2025-08-15 16:42:21 +00:00

The files here use the LLVM FileCheck framework, documented at https://llvm.org/docs/CommandGuide/FileCheck.html.

One extension worth noting is the use of revisions as custom prefixes for FileCheck. If your codegen test has different behavior based on the chosen target or different compiler flags that you want to exercise, you can use a revisions annotation, like so:

// revisions: aaa bbb
// [bbb] compile-flags: --flags-for-bbb

After specifying those variations, you can write different expected, or explicitly unexpected output by using <prefix>-SAME: and <prefix>-NOT:, like so:

// CHECK: expected code
// aaa-SAME: emitted-only-for-aaa
// aaa-NOT:                        emitted-only-for-bbb
// bbb-NOT:  emitted-only-for-aaa
// bbb-SAME:                       emitted-only-for-bbb