Merge commit 'ba315abda7' into sync_cg_clif-2025-03-30

compiler/rustc_codegen_cranelift/scripts/setup_rust_fork.sh

@@ -43,8 +43,31 @@ verbose-tests = false
 # disabled bootstrap will crash trying to copy llvm tools for the bootstrap
 # compiler.
 llvm-tools = false
+std-features = ["panic-unwind", "compiler-builtins-no-f16-f128"]
 
 EOF
+
+cat <<EOF | git apply -
+diff --git a/src/bootstrap/src/core/config/config.rs b/src/bootstrap/src/core/config/config.rs
+index cf4ef4ee310..fe78560fcaf 100644
+--- a/src/bootstrap/src/core/config/config.rs
++++ b/src/bootstrap/src/core/config/config.rs
+@@ -3138,13 +3138,6 @@ fn parse_download_ci_llvm(
+                     );
+                 }
+
+-                if b && self.is_running_on_ci {
+-                    // On CI, we must always rebuild LLVM if there were any modifications to it
+-                    panic!(
+-                        "\`llvm.download-ci-llvm\` cannot be set to \`true\` on CI. Use \`if-unchanged\` instead."
+-                    );
+-                }
+-
+                 // If download-ci-llvm=true we also want to check that CI llvm is available
+                 b && llvm::is_ci_llvm_available_for_target(self, asserts)
+             }
+EOF
+
 popd
 
 # Allow the testsuite to use llvm tools