rust-lang · tgross35 · Aug 15, 2025
diff --git a/src/tools/compiletest/src/runtest.rs b/src/tools/compiletest/src/runtest.rs
@@ -2071,25 +2071,6 @@ impl<'test> TestCx<'test> {
         let mut filecheck = Command::new(self.config.llvm_filecheck.as_ref().unwrap());
         filecheck.arg("--input-file").arg(output).arg(&self.testpaths.file);
 
-        // Because we use custom prefixes, we also have to register the default prefix.
-        filecheck.arg("--check-prefix=CHECK");
-
-        // FIXME(#134510): auto-registering revision names as check prefix is a bit sketchy, and
-        // that having to pass `--allow-unused-prefix` is an unfortunate side-effect of not knowing
-        // whether the test author actually wanted revision-specific check prefixes or not.
-        //
-        // TL;DR We may not want to conflate `compiletest` revisions and `FileCheck` prefixes.
-
-        // HACK: tests are allowed to use a revision name as a check prefix.
-        if let Some(rev) = self.revision {
-            filecheck.arg("--check-prefix").arg(rev);
-        }
-
-        // HACK: the filecheck tool normally fails if a prefix is defined but not used. However,
-        // sometimes revisions are used to specify *compiletest* directives which are not FileCheck
-        // concerns.
-        filecheck.arg("--allow-unused-prefixes");
-
         // Provide more context on failures.
         filecheck.args(&["--dump-input-context", "100"]);
 

diff --git a/tests/assembly-llvm/aarch64-pointer-auth.rs b/tests/assembly-llvm/aarch64-pointer-auth.rs
@@ -6,8 +6,11 @@
 //@ needs-llvm-components: aarch64
 //@ compile-flags: --target aarch64-unknown-linux-gnu
 //@ [PACRET] compile-flags: -Z branch-protection=pac-ret,leaf
+//@ [PACRET] filecheck-flags: --check-prefixes=PACRET
 //@ [PAUTHLR_NOP] compile-flags: -Z branch-protection=pac-ret,pc,leaf
+//@ [PAUTHLR_NOP] filecheck-flags: --check-prefixes=PAUTHLR_NOP
 //@ [PAUTHLR] compile-flags: -C target-feature=+pauth-lr -Z branch-protection=pac-ret,pc,leaf
+//@ [PAUTHLR] filecheck-flags: --check-prefixes=PAUTHLR
 
 #![feature(no_core, lang_items)]
 #![no_std]

diff --git a/tests/assembly-llvm/asm/arm-types.rs b/tests/assembly-llvm/asm/arm-types.rs
@@ -7,6 +7,8 @@
 //@[d32] compile-flags: -C target-feature=+d32
 //@[neon] compile-flags: -C target-feature=+neon --cfg d32
 //@[neon] filecheck-flags: --check-prefix d32
+//@[d32] filecheck-flags: --check-prefixes=CHECK,d32
+//@[neon] filecheck-flags: --check-prefixes=CHECK,neon
 //@ needs-llvm-components: arm
 
 #![feature(no_core, repr_simd, f16)]

diff --git a/tests/assembly-llvm/asm/loongarch-type.rs b/tests/assembly-llvm/asm/loongarch-type.rs
@@ -8,6 +8,7 @@
 
 //@[loongarch64] compile-flags: --target loongarch64-unknown-none
 //@[loongarch64] needs-llvm-components: loongarch
+//@[loongarch64] filecheck-flags: --check-prefixes=CHECK,loongarch64
 
 //@ compile-flags: -Zmerge-functions=disabled
 

diff --git a/tests/assembly-llvm/asm/mips-types.rs b/tests/assembly-llvm/asm/mips-types.rs
@@ -5,6 +5,8 @@
 //@[mips32] needs-llvm-components: mips
 //@[mips64] compile-flags: --target mips64-unknown-linux-gnuabi64
 //@[mips64] needs-llvm-components: mips
+//@[mips32] filecheck-flags: --check-prefixes=CHECK,mips32
+//@[mips64] filecheck-flags: --check-prefixes=CHECK,mips64
 //@ compile-flags: -Zmerge-functions=disabled
 
 #![feature(no_core, asm_experimental_arch)]

diff --git a/tests/assembly-llvm/asm/powerpc-types.rs b/tests/assembly-llvm/asm/powerpc-types.rs
@@ -4,12 +4,16 @@
 //@[powerpc] compile-flags: --target powerpc-unknown-linux-gnu
 //@[powerpc] needs-llvm-components: powerpc
 //@[powerpc_altivec] compile-flags: --target powerpc-unknown-linux-gnu -C target-feature=+altivec --cfg altivec
+//@[powerpc_altivec] filecheck-flags: --check-prefixes=CHECK,powerpc_altivec
 //@[powerpc_altivec] needs-llvm-components: powerpc
 //@[powerpc_vsx] compile-flags: --target powerpc-unknown-linux-gnu -C target-feature=+altivec,+vsx --cfg altivec --cfg vsx
+//@[powerpc_vsx] filecheck-flags: --check-prefixes=CHECK,powerpc_vsx
 //@[powerpc_vsx] needs-llvm-components: powerpc
 //@[powerpc64] compile-flags: --target powerpc64-unknown-linux-gnu --cfg altivec
+//@[powerpc64] filecheck-flags: --check-prefixes=CHECK,powerpc64
 //@[powerpc64] needs-llvm-components: powerpc
 //@[powerpc64_vsx] compile-flags: --target powerpc64-unknown-linux-gnu -C target-feature=+vsx --cfg altivec --cfg vsx
+//@[powerpc64_vsx] filecheck-flags: --check-prefixes=CHECK,powerpc64_vsx
 //@[powerpc64_vsx] needs-llvm-components: powerpc
 //@ compile-flags: -Zmerge-functions=disabled
 

diff --git a/tests/assembly-llvm/asm/riscv-types.rs b/tests/assembly-llvm/asm/riscv-types.rs
@@ -4,28 +4,30 @@
 
 //@[riscv64] compile-flags: --target riscv64imac-unknown-none-elf
 //@[riscv64] needs-llvm-components: riscv
+//@[riscv64] filecheck-flags: --check-prefixes=CHECK,riscv64
 
 //@[riscv32] compile-flags: --target riscv32imac-unknown-none-elf
 //@[riscv32] needs-llvm-components: riscv
 
 //@[riscv64-zfhmin] compile-flags: --target riscv64imac-unknown-none-elf --cfg riscv64
 //@[riscv64-zfhmin] needs-llvm-components: riscv
 //@[riscv64-zfhmin] compile-flags: -C target-feature=+zfhmin
-//@[riscv64-zfhmin] filecheck-flags: --check-prefix riscv64
+//@[riscv64-zfhmin] filecheck-flags: --check-prefixes=CHECK,riscv64
 
 //@[riscv32-zfhmin] compile-flags: --target riscv32imac-unknown-none-elf
 //@[riscv32-zfhmin] needs-llvm-components: riscv
 //@[riscv32-zfhmin] compile-flags: -C target-feature=+zfhmin
+//@[riscv32-zfhmin] filecheck-flags: --check-prefixes=CHECK,zfhmin
 
 //@[riscv64-zfh] compile-flags: --target riscv64imac-unknown-none-elf --cfg riscv64
 //@[riscv64-zfh] needs-llvm-components: riscv
 //@[riscv64-zfh] compile-flags: -C target-feature=+zfh
-//@[riscv64-zfh] filecheck-flags: --check-prefix riscv64 --check-prefix zfhmin
+//@[riscv64-zfh] filecheck-flags: --check-prefixes=CHECK,riscv64 --check-prefix zfhmin
 
 //@[riscv32-zfh] compile-flags: --target riscv32imac-unknown-none-elf
 //@[riscv32-zfh] needs-llvm-components: riscv
 //@[riscv32-zfh] compile-flags: -C target-feature=+zfh
-//@[riscv32-zfh] filecheck-flags: --check-prefix zfhmin
+//@[riscv32-zfh] filecheck-flags: --check-prefixes=CHECK,zfhmin
 
 //@ compile-flags: -C target-feature=+d
 //@ compile-flags: -Zmerge-functions=disabled

diff --git a/tests/assembly-llvm/asm/s390x-types.rs b/tests/assembly-llvm/asm/s390x-types.rs
@@ -5,6 +5,7 @@
 //@[s390x] needs-llvm-components: systemz
 //@[s390x_vector] compile-flags: --target s390x-unknown-linux-gnu -C target-feature=+vector
 //@[s390x_vector] needs-llvm-components: systemz
+//@[s390x_vector] filecheck-flags: --check-prefixes=CHECK,s390x_vector
 //@ compile-flags: -Zmerge-functions=disabled
 
 #![feature(no_core, repr_simd, f128)]

diff --git a/tests/assembly-llvm/asm/sparc-types.rs b/tests/assembly-llvm/asm/sparc-types.rs
@@ -7,6 +7,7 @@
 //@[sparcv8plus] needs-llvm-components: sparc
 //@[sparc64] compile-flags: --target sparc64-unknown-linux-gnu
 //@[sparc64] needs-llvm-components: sparc
+//@[sparc64] filecheck-flags: --check-prefixes=CHECK,sparc64
 //@ compile-flags: -Zmerge-functions=disabled
 
 #![feature(no_core, asm_experimental_arch)]

diff --git a/tests/assembly-llvm/asm/x86-modifiers.rs b/tests/assembly-llvm/asm/x86-modifiers.rs
@@ -6,6 +6,8 @@
 //@[x86_64] needs-llvm-components: x86
 //@[i686] compile-flags: --target i686-unknown-linux-gnu
 //@[i686] needs-llvm-components: x86
+//@[x86_64] filecheck-flags: --check-prefixes=CHECK,x86_64
+//@[i686] filecheck-flags: --check-prefixes=CHECK,i686
 //@ compile-flags: -C llvm-args=--x86-asm-syntax=intel
 //@ compile-flags: -C target-feature=+avx512bw
 //@ compile-flags: -Zmerge-functions=disabled

diff --git a/tests/assembly-llvm/asm/x86-types.rs b/tests/assembly-llvm/asm/x86-types.rs
@@ -5,6 +5,8 @@
 //@[x86_64] needs-llvm-components: x86
 //@[i686] compile-flags: --target i686-unknown-linux-gnu
 //@[i686] needs-llvm-components: x86
+//@[x86_64] filecheck-flags: --check-prefixes=CHECK,x86_64
+//@[i686] filecheck-flags: --check-prefixes=CHECK,i686
 //@ compile-flags: -C llvm-args=--x86-asm-syntax=intel
 //@ compile-flags: -C target-feature=+avx512bw
 //@ compile-flags: -Zmerge-functions=disabled

diff --git a/tests/assembly-llvm/nvptx-safe-naming.rs b/tests/assembly-llvm/nvptx-safe-naming.rs
@@ -4,6 +4,8 @@
 //@ revisions: LLVM20 LLVM21
 //@ [LLVM21] min-llvm-version: 21
 //@ [LLVM20] max-llvm-major-version: 20
+//@ [LLVM21] filecheck-flags: --check-prefixes=CHECK,LLVM21
+//@ [LLVM20] filecheck-flags: --check-prefixes=CHECK,LLVM20
 
 #![feature(abi_ptx)]
 #![no_std]

diff --git a/tests/assembly-llvm/powerpc64-struct-abi.rs b/tests/assembly-llvm/powerpc64-struct-abi.rs
@@ -3,18 +3,17 @@
 //@ assembly-output: emit-asm
 //@ compile-flags: -Copt-level=3
 //@[elfv1-be] compile-flags: --target powerpc64-unknown-linux-gnu
+//@[elfv1-be] filecheck-flags: --check-prefixes=CHECK,elfv1-be,be,elf
 //@[elfv1-be] needs-llvm-components: powerpc
 //@[elfv2-be] compile-flags: --target powerpc64-unknown-linux-musl
+//@[elfv2-be] filecheck-flags: --check-prefixes=CHECK,elfv2-be,be,elf
 //@[elfv2-be] needs-llvm-components: powerpc
 //@[elfv2-le] compile-flags: --target powerpc64le-unknown-linux-gnu -C target-cpu=pwr8
+//@[elfv2-le] filecheck-flags: --check-prefixes=CHECK,elfv2-le,elf
 //@[elfv2-le] needs-llvm-components: powerpc
 //@[aix] compile-flags: --target powerpc64-ibm-aix
+//@[aix] filecheck-flags: --check-prefixes=CHECK,aix
 //@[aix] needs-llvm-components: powerpc
-//@[elfv1-be] filecheck-flags: --check-prefix be
-//@[elfv2-be] filecheck-flags: --check-prefix be
-//@[elfv1-be] filecheck-flags: --check-prefix elf
-//@[elfv2-be] filecheck-flags: --check-prefix elf
-//@[elfv2-le] filecheck-flags: --check-prefix elf
 
 #![feature(no_core, lang_items)]
 #![no_std]

diff --git a/tests/assembly-llvm/riscv-soft-abi-with-float-features.rs b/tests/assembly-llvm/riscv-soft-abi-with-float-features.rs
@@ -5,6 +5,8 @@
 //@ revisions: LLVM-PRE-20 LLVM-POST-20
 //@ [LLVM-PRE-20] max-llvm-major-version: 19
 //@ [LLVM-POST-20] min-llvm-version: 20
+//@ [LLVM-PRE-20] filecheck-flags: --check-prefixes=CHECK,LLVM-PRE-20
+//@ [LLVM-POST-20] filecheck-flags: --check-prefixes=CHECK,LLVM-POST-20
 
 #![feature(no_core, lang_items, f16)]
 #![crate_type = "lib"]

diff --git a/tests/assembly-llvm/rust-abi-arg-attr.rs b/tests/assembly-llvm/rust-abi-arg-attr.rs
@@ -8,6 +8,9 @@
 //@ [riscv64-zbb] needs-llvm-components: riscv
 //@ [loongarch64] compile-flags: --target loongarch64-unknown-linux-gnu
 //@ [loongarch64] needs-llvm-components: loongarch
+//@ [riscv64] filecheck-flags: --check-prefixes=CHECK,riscv64
+//@ [riscv64-zbb] filecheck-flags: --check-prefixes=CHECK,riscv64-zbb
+//@ [loongarch64] filecheck-flags: --check-prefixes=CHECK,loongarch64
 
 #![feature(no_core, lang_items, intrinsics, rustc_attrs)]
 #![crate_type = "lib"]

diff --git a/tests/assembly-llvm/s390x-backchain-toggle.rs b/tests/assembly-llvm/s390x-backchain-toggle.rs
@@ -5,6 +5,9 @@
 //@ needs-llvm-components: systemz
 //@[enable-backchain] compile-flags: -Ctarget-feature=+backchain
 //@[disable-backchain] compile-flags: -Ctarget-feature=-backchain
+//@[enable-backchain] filecheck-flags: --check-prefixes=CHECK,enable-backchain
+//@[disable-backchain] filecheck-flags: --check-prefixes=CHECK,disable-backchain
+
 #![feature(no_core, lang_items)]
 #![no_std]
 #![no_core]

diff --git a/tests/assembly-llvm/s390x-vector-abi.rs b/tests/assembly-llvm/s390x-vector-abi.rs
@@ -3,10 +3,12 @@
 //@ assembly-output: emit-asm
 //@ compile-flags: -Copt-level=3 -Z merge-functions=disabled
 //@[z10] compile-flags: --target s390x-unknown-linux-gnu  -C target-cpu=z10 --cfg no_vector
+//@[z10] filecheck-flags: --check-prefixes=CHECK,z10
 //@[z10] needs-llvm-components: systemz
 //@[z10_vector] compile-flags: --target s390x-unknown-linux-gnu -C target-cpu=z10 -C target-feature=+vector
 //@[z10_vector] needs-llvm-components: systemz
 //@[z13] compile-flags: --target s390x-unknown-linux-gnu -C target-cpu=z13
+//@[z13] filecheck-flags: --check-prefixes=CHECK,z13
 //@[z13] needs-llvm-components: systemz
 //@[z13_no_vector] compile-flags: --target s390x-unknown-linux-gnu -C target-cpu=z13 -C target-feature=-vector --cfg no_vector
 //@[z13_no_vector] needs-llvm-components: systemz

diff --git a/tests/assembly-llvm/simd-bitmask.rs b/tests/assembly-llvm/simd-bitmask.rs
@@ -1,14 +1,18 @@
 //@ add-core-stubs
 //@ revisions: x86 x86-avx2 x86-avx512 aarch64
 //@ [x86] compile-flags: --target=x86_64-unknown-linux-gnu -C llvm-args=-x86-asm-syntax=intel
+//@ [x86] filecheck-flags: --check-prefixes=CHECK,x86
 //@ [x86] needs-llvm-components: x86
 //@ [x86-avx2] compile-flags: --target=x86_64-unknown-linux-gnu -C llvm-args=-x86-asm-syntax=intel
 //@ [x86-avx2] compile-flags: -C target-feature=+avx2
+//@ [x86-avx2] filecheck-flags: --check-prefixes=CHECK,x86-avx2
 //@ [x86-avx2] needs-llvm-components: x86
 //@ [x86-avx512] compile-flags: --target=x86_64-unknown-linux-gnu -C llvm-args=-x86-asm-syntax=intel
 //@ [x86-avx512] compile-flags: -C target-feature=+avx512f,+avx512vl,+avx512bw,+avx512dq
+//@ [x86-avx512] filecheck-flags: --check-prefixes=CHECK,x86-avx512
 //@ [x86-avx512] needs-llvm-components: x86
 //@ [aarch64] compile-flags: --target=aarch64-unknown-linux-gnu
+//@ [aarch64] filecheck-flags: --check-prefixes=CHECK,aarch64
 //@ [aarch64] needs-llvm-components: aarch64
 //@ assembly-output: emit-asm
 //@ compile-flags: --crate-type=lib -Copt-level=3 -C panic=abort

diff --git a/tests/assembly-llvm/simd-intrinsic-gather.rs b/tests/assembly-llvm/simd-intrinsic-gather.rs
@@ -3,6 +3,7 @@
 //@ [x86-avx512] compile-flags: --target=x86_64-unknown-linux-gnu -C llvm-args=-x86-asm-syntax=intel
 //@ [x86-avx512] compile-flags: -C target-feature=+avx512f,+avx512vl,+avx512bw,+avx512dq
 //@ [x86-avx512] needs-llvm-components: x86
+//@ [x86-avx512] filecheck-flags: --check-prefixes=CHECK,x86-avx512
 //@ assembly-output: emit-asm
 //@ compile-flags: --crate-type=lib -Copt-level=3 -C panic=abort
 

diff --git a/tests/assembly-llvm/simd-intrinsic-mask-load.rs b/tests/assembly-llvm/simd-intrinsic-mask-load.rs
@@ -2,9 +2,11 @@
 //@ revisions: x86-avx2 x86-avx512
 //@ [x86-avx2] compile-flags: --target=x86_64-unknown-linux-gnu -C llvm-args=-x86-asm-syntax=intel
 //@ [x86-avx2] compile-flags: -C target-feature=+avx2
+//@ [x86-avx2] filecheck-flags: --check-prefixes=CHECK,x86-avx2
 //@ [x86-avx2] needs-llvm-components: x86
 //@ [x86-avx512] compile-flags: --target=x86_64-unknown-linux-gnu -C llvm-args=-x86-asm-syntax=intel
 //@ [x86-avx512] compile-flags: -C target-feature=+avx512f,+avx512vl,+avx512bw,+avx512dq
+//@ [x86-avx512] filecheck-flags: --check-prefixes=CHECK,x86-avx512
 //@ [x86-avx512] needs-llvm-components: x86
 //@ assembly-output: emit-asm
 //@ compile-flags: --crate-type=lib -Copt-level=3 -C panic=abort

diff --git a/tests/assembly-llvm/simd-intrinsic-mask-reduce.rs b/tests/assembly-llvm/simd-intrinsic-mask-reduce.rs
@@ -4,8 +4,10 @@
 //@ [x86] compile-flags: --target=x86_64-unknown-linux-gnu -C llvm-args=-x86-asm-syntax=intel
 // Set the base cpu explicitly, in case the default has been changed.
 //@ [x86] compile-flags: -C target-cpu=x86-64
+//@ [x86] filecheck-flags: --check-prefixes=CHECK,x86
 //@ [x86] needs-llvm-components: x86
 //@ [aarch64] compile-flags: --target=aarch64-unknown-linux-gnu
+//@ [aarch64] filecheck-flags: --check-prefixes=CHECK,aarch64
 //@ [aarch64] needs-llvm-components: aarch64
 //@ assembly-output: emit-asm
 //@ compile-flags: --crate-type=lib -Copt-level=3 -C panic=abort

diff --git a/tests/assembly-llvm/simd-intrinsic-mask-store.rs b/tests/assembly-llvm/simd-intrinsic-mask-store.rs
@@ -3,9 +3,11 @@
 //@ [x86-avx2] compile-flags: --target=x86_64-unknown-linux-gnu -C llvm-args=-x86-asm-syntax=intel
 //@ [x86-avx2] compile-flags: -C target-feature=+avx2
 //@ [x86-avx2] needs-llvm-components: x86
+//@ [x86-avx2] filecheck-flags: --check-prefixes=CHECK,x86-avx2
 //@ [x86-avx512] compile-flags: --target=x86_64-unknown-linux-gnu -C llvm-args=-x86-asm-syntax=intel
 //@ [x86-avx512] compile-flags: -C target-feature=+avx512f,+avx512vl,+avx512bw,+avx512dq
 //@ [x86-avx512] needs-llvm-components: x86
+//@ [x86-avx512] filecheck-flags: --check-prefixes=CHECK,x86-avx512
 //@ assembly-output: emit-asm
 //@ compile-flags: --crate-type=lib -Copt-level=3 -C panic=abort
 

diff --git a/tests/assembly-llvm/simd-intrinsic-scatter.rs b/tests/assembly-llvm/simd-intrinsic-scatter.rs
@@ -3,6 +3,7 @@
 //@ [x86-avx512] compile-flags: --target=x86_64-unknown-linux-gnu -C llvm-args=-x86-asm-syntax=intel
 //@ [x86-avx512] compile-flags: -C target-feature=+avx512f,+avx512vl,+avx512bw,+avx512dq
 //@ [x86-avx512] needs-llvm-components: x86
+//@ [x86-avx512] filecheck-flags: --check-prefixes=CHECK,x86-avx512
 //@ assembly-output: emit-asm
 //@ compile-flags: --crate-type=lib -Copt-level=3 -C panic=abort
 

diff --git a/tests/assembly-llvm/simd-intrinsic-select.rs b/tests/assembly-llvm/simd-intrinsic-select.rs
@@ -8,6 +8,9 @@
 //@ [x86-avx512] needs-llvm-components: x86
 //@ [aarch64] compile-flags: --target=aarch64-unknown-linux-gnu
 //@ [aarch64] needs-llvm-components: aarch64
+//@ [x86-avx2] filecheck-flags: --check-prefixes=CHECK,x86-avx2
+//@ [x86-avx512] filecheck-flags: --check-prefixes=CHECK,x86-avx512
+//@ [aarch64] filecheck-flags: --check-prefixes=CHECK,aarch64
 //@ assembly-output: emit-asm
 //@ compile-flags: --crate-type=lib -Copt-level=3 -C panic=abort
 

diff --git a/tests/assembly-llvm/simd/reduce-fadd-unordered.rs b/tests/assembly-llvm/simd/reduce-fadd-unordered.rs
@@ -5,7 +5,10 @@
 //@[aarch64] only-aarch64
 //@[x86_64] only-x86_64
 //@[x86_64] compile-flags: -Ctarget-feature=+sse3
+//@[aarch64] filecheck-flags: --check-prefixes=CHECK,aarch64
+//@[x86_64] filecheck-flags: --check-prefixes=CHECK,x86_64
 //@ ignore-sgx Test incompatible with LVI mitigations
+
 #![feature(portable_simd)]
 #![feature(core_intrinsics)]
 use std::intrinsics::simd as intrinsics;

diff --git a/tests/assembly-llvm/static-relocation-model.rs b/tests/assembly-llvm/static-relocation-model.rs
@@ -7,6 +7,9 @@
 //@ [A64] needs-llvm-components: aarch64
 //@ [ppc64le] compile-flags: --target powerpc64le-unknown-linux-gnu -Crelocation-model=static
 //@ [ppc64le] needs-llvm-components: powerpc
+//@ [x64] filecheck-flags: --check-prefixes=CHECK,x64
+//@ [A64] filecheck-flags: --check-prefixes=CHECK,A64
+//@ [ppc64le] filecheck-flags: --check-prefixes=CHECK,ppc64le
 
 #![feature(no_core, lang_items)]
 #![no_core]

diff --git a/tests/assembly-llvm/x86-return-float.rs b/tests/assembly-llvm/x86-return-float.rs
@@ -15,6 +15,8 @@
 //@[win] needs-llvm-components: x86
 //@[linux] compile-flags: --target i686-unknown-linux-gnu
 //@[win] compile-flags: --target i686-pc-windows-msvc
+//@[linux] filecheck-flags: --check-prefixes=CHECK,linux
+//@[win] filecheck-flags: --check-prefixes=CHECK,win
 
 #![crate_type = "lib"]
 #![feature(f16, f128)]

diff --git a/tests/assembly-llvm/x86_64-windows-i128-abi.rs b/tests/assembly-llvm/x86_64-windows-i128-abi.rs
@@ -6,6 +6,8 @@
 //@[msvc] needs-llvm-components: x86
 //@[softfloat] compile-flags: --target x86_64-unknown-uefi
 //@[softfloat] needs-llvm-components: x86
+//@[msvc] filecheck-flags: --check-prefixes=CHECK,msvc
+//@[softfloat] filecheck-flags: --check-prefixes=CHECK,softfloat
 
 #![feature(no_core)]
 #![no_core]

diff --git a/tests/codegen-llvm/README.md b/tests/codegen-llvm/README.md
@@ -1,24 +1,25 @@
 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:
+If your codegen test has different behavior based on the chosen target or
+different compiler flags that you want to exercise, you can set different
+filecheck prefixes for each revision:
 
 ```rust
 // revisions: aaa bbb
 // [bbb] compile-flags: --flags-for-bbb
+// [aaa] filecheck-flags: --check-prefixes=ALL,AAA
+// [bbb] filecheck-flags: --check-prefixes=ALL,BBB
 ```
 
 After specifying those variations, you can write different expected, or
 explicitly *unexpected* output by using `<prefix>-SAME:` and `<prefix>-NOT:`,
 like so:
 
 ```rust
-// 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
+// ALL: 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
 ```
diff --git a/tests/codegen-llvm/aarch64-struct-align-128.rs b/tests/codegen-llvm/aarch64-struct-align-128.rs
@@ -5,6 +5,9 @@
 //@[linux] compile-flags: --target aarch64-unknown-linux-gnu
 //@[darwin] compile-flags: --target aarch64-apple-darwin
 //@[win] compile-flags: --target aarch64-pc-windows-msvc
+//@[linux] filecheck-flags: --check-prefixes=linux
+//@[darwin] filecheck-flags: --check-prefixes=darwin
+//@[win] filecheck-flags: --check-prefixes=win
 //@[linux] needs-llvm-components: aarch64
 //@[darwin] needs-llvm-components: aarch64
 //@[win] needs-llvm-components: aarch64