GVN: Compare discriminants with constant

[dianqk]

r? @ghost

[rust-log-analyzer]

The job aarch64-gnu-llvm-20-1 failed! Check out the build log: (web) (plain enhanced) (plain)

Click to see the possible cause of the failure (guessed by this bot)

   Compiling icu_locale_core v2.0.0
error[E0308]: mismatched types
   --> compiler/rustc_span/src/source_map.rs:995:26
    |
995 |         if (!forwards && end_index == usize::MIN) || (forwards && start_index == usize::MAX) {
    |             ---------    ^^^^^^^^^ expected `bool`, found `usize`
    |             |
    |             expected because this is `bool`

error[E0308]: mismatched types
   --> compiler/rustc_span/src/source_map.rs:995:39
    |
973 |     #[instrument(skip(self, sp))]
    |     ----------------------------- expected because this is `bool`
...
995 |         if (!forwards && end_index == usize::MIN) || (forwards && start_index == usize::MAX) {
    |                                       ^^^^^^^^^^ expected `bool`, found `usize`

error[E0308]: mismatched types
   --> compiler/rustc_span/src/source_map.rs:995:67
    |
995 |         if (!forwards && end_index == usize::MIN) || (forwards && start_index == usize::MAX) {
    |                                                       --------    ^^^^^^^^^^^ expected `bool`, found `usize`
    |                                                       |
    |                                                       expected because this is `bool`

error[E0308]: mismatched types
   --> compiler/rustc_span/src/source_map.rs:995:82
    |
973 |     #[instrument(skip(self, sp))]
    |     ----------------------------- expected because this is `bool`
...
995 |         if (!forwards && end_index == usize::MIN) || (forwards && start_index == usize::MAX) {
    |                                                                                  ^^^^^^^^^^ expected `bool`, found `usize`

error[E0308]: mismatched types
    --> compiler/rustc_span/src/source_map.rs:1003:39
     |
 973 |     #[instrument(skip(self, sp))]
     |     ----------------------------- expected because this is `bool`
...
1003 |         if start_index > end_index || end_index > source_len - 1 {
     |                                       ^^^^^^^^^ expected `bool`, found `usize`

error[E0308]: mismatched types
    --> compiler/rustc_span/src/source_map.rs:1003:51
     |
 973 |     #[instrument(skip(self, sp))]
     |     ----------------------------- expected because this is `bool`
...
1003 |         if start_index > end_index || end_index > source_len - 1 {
     |                                                   ^^^^^^^^^^ expected `bool`, found `usize`

error[E0369]: cannot subtract `{integer}` from `bool`
    --> compiler/rustc_span/src/source_map.rs:1003:62
     |
 973 |     #[instrument(skip(self, sp))]
     |     ----------------------------- bool
...
1003 |         if start_index > end_index || end_index > source_len - 1 {
     |                                                              ^ - {integer}

[RUSTC-TIMING] rustc_data_structures test:false 6.343
   Compiling ppv-lite86 v0.2.21
[RUSTC-TIMING] ppv_lite86 test:false 0.495
   Compiling unic-langid v0.9.6