Rollup merge of #129350 - krasimirgg:llvm20, r=nikic

adapt integer comparison tests for LLVM 20 IR changes

The LLVM commit llvm/llvm-project@abf69a1 changed the IR in a few comparison tests:
https://buildkite.com/llvm-project/rust-llvm-integrate-prototype/builds/30500#01917017-26fe-4a4d-956b-725a2903e5a8

Adapted accordingly.

````@rustbot```` label: +llvm-main
r? ````@nikic````

tests/assembly/x86_64-cmp.rs

@@ -1,6 +1,9 @@
-//@ revisions: DEBUG OPTIM
+//@ revisions: DEBUG LLVM-PRE-20-OPTIM LLVM-20-OPTIM
 //@ [DEBUG] compile-flags: -C opt-level=0
-//@ [OPTIM] compile-flags: -C opt-level=3
+//@ [LLVM-PRE-20-OPTIM] compile-flags: -C opt-level=3
+//@ [LLVM-PRE-20-OPTIM] ignore-llvm-version: 20 - 99
+//@ [LLVM-20-OPTIM] compile-flags: -C opt-level=3
+//@ [LLVM-20-OPTIM] min-llvm-version: 20
 //@ assembly-output: emit-asm
 //@ compile-flags: --crate-type=lib -C llvm-args=-x86-asm-syntax=intel
 //@ only-x86_64
@@ -21,12 +24,18 @@ pub fn signed_cmp(a: i16, b: i16) -> std::cmp::Ordering {
     // DEBUG: and
     // DEBUG: sub
 
-    // OPTIM: xor
-    // OPTIM: cmp
-    // OPTIM: setne
-    // OPTIM: mov
-    // OPTIM: cmovge
-    // OPTIM: ret
+    // LLVM-PRE-20-OPTIM: xor
+    // LLVM-PRE-20-OPTIM: cmp
+    // LLVM-PRE-20-OPTIM: setne
+    // LLVM-PRE-20-OPTIM: mov
+    // LLVM-PRE-20-OPTIM: cmovge
+    // LLVM-PRE-20-OPTIM: ret
+    //
+    // LLVM-20-OPTIM: cmp
+    // LLVM-20-OPTIM: setl
+    // LLVM-20-OPTIM: setg
+    // LLVM-20-OPTIM: sub
+    // LLVM-20-OPTIM: ret
     three_way_compare(a, b)
 }
 
@@ -41,11 +50,16 @@ pub fn unsigned_cmp(a: u16, b: u16) -> std::cmp::Ordering {
     // DEBUG: and
     // DEBUG: sub
 
-    // OPTIM: xor
-    // OPTIM: cmp
-    // OPTIM: setne
-    // OPTIM: mov
-    // OPTIM: cmovae
-    // OPTIM: ret
+    // LLVM-PRE-20-OPTIM: xor
+    // LLVM-PRE-20-OPTIM: cmp
+    // LLVM-PRE-20-OPTIM: setne
+    // LLVM-PRE-20-OPTIM: mov
+    // LLVM-PRE-20-OPTIM: cmovae
+    // LLVM-PRE-20-OPTIM: ret
+    //
+    // LLVM-20-OPTIM: cmp
+    // LLVM-20-OPTIM: seta
+    // LLVM-20-OPTIM: sbb
+    // LLVM-20-OPTIM: ret
     three_way_compare(a, b)
 }

tests/codegen/integer-cmp.rs

@@ -1,6 +1,9 @@
 // This is test for more optimal Ord implementation for integers.
 // See <https://github.com/rust-lang/rust/issues/63758> for more info.
 
+//@ revisions: llvm-pre-20 llvm-20
+//@ [llvm-20] min-llvm-version: 20
+//@ [llvm-pre-20] ignore-llvm-version: 20 - 99
 //@ compile-flags: -C opt-level=3
 
 #![crate_type = "lib"]
@@ -10,19 +13,21 @@ use std::cmp::Ordering;
 // CHECK-LABEL: @cmp_signed
 #[no_mangle]
 pub fn cmp_signed(a: i64, b: i64) -> Ordering {
-    // CHECK: icmp slt
-    // CHECK: icmp ne
-    // CHECK: zext i1
-    // CHECK: select i1
+    // llvm-20: @llvm.scmp.i8.i64
+    // llvm-pre-20: icmp slt
+    // llvm-pre-20: icmp ne
+    // llvm-pre-20: zext i1
+    // llvm-pre-20: select i1
     a.cmp(&b)
 }
 
 // CHECK-LABEL: @cmp_unsigned
 #[no_mangle]
 pub fn cmp_unsigned(a: u32, b: u32) -> Ordering {
-    // CHECK: icmp ult
-    // CHECK: icmp ne
-    // CHECK: zext i1
-    // CHECK: select i1
+    // llvm-20: @llvm.ucmp.i8.i32
+    // llvm-pre-20: icmp ult
+    // llvm-pre-20: icmp ne
+    // llvm-pre-20: zext i1
+    // llvm-pre-20: select i1
     a.cmp(&b)
 }