stdarch-test: [us]shll[tb] have no aliases

SVE's `[us]shll[tb]` intructions have no aliases unlike Neon's
`[us]hll{2}` so this logic needs adjusted to not accidentally rewrite
the instruction.

Author: davidtwco

crates/stdarch-test/src/disassembly.rs

@@ -158,16 +158,26 @@ fn parse(output: &str) -> HashSet<Function> {
             };
 
             if cfg!(any(target_arch = "aarch64", target_arch = "arm64ec")) {
-                // Normalize [us]shll.* ..., #0 instructions to the preferred form: [us]xtl.* ...
-                // as neither LLVM objdump nor dumpbin does that.
-                // See https://developer.arm.com/documentation/ddi0602/latest/SIMD-FP-Instructions/UXTL--UXTL2--Unsigned-extend-Long--an-alias-of-USHLL--USHLL2-
-                // and https://developer.arm.com/documentation/ddi0602/latest/SIMD-FP-Instructions/SXTL--SXTL2--Signed-extend-Long--an-alias-of-SSHLL--SSHLL2-
-                // for details.
+                // Normalize `[us]shll{2}.* ..., #0` instructions to the preferred
+                // form: `[us]xtl{2}.* ...` as neither LLVM objdump nor dumpbin does that.
+                //
+                // SVE has `[us]shll[tb]` instructions that don't have an equivalent alias.
+                //
+                // See Arm documentation for details:
+                //
+                // - https://developer.arm.com/documentation/ddi0602/2026-03/SIMD-FP-Instructions/UXTL--UXTL2--Unsigned-extend-long--an-alias-of-USHLL--USHLL2-?lang=en
+                // - https://developer.arm.com/documentation/ddi0602/2026-03/SIMD-FP-Instructions/SXTL--SXTL2--Signed-extend-long--an-alias-of-SSHLL--SSHLL2-?lang=en
                 fn is_shll(instr: &str) -> bool {
                     if cfg!(target_env = "msvc") {
-                        instr.starts_with("ushll") || instr.starts_with("sshll")
+                        instr == "ushll"
+                            || instr == "ushll2"
+                            || instr == "sshll"
+                            || instr == "sshll2"
                     } else {
-                        instr.starts_with("ushll.") || instr.starts_with("sshll.")
+                        instr == "ushll."
+                            || instr == "ushll2."
+                            || instr == "sshll."
+                            || instr == "sshll2."
                     }
                 }
                 match (parts.first(), parts.last()) {