Extend the chaining logic to slices too

1 files changed, 49 insertions, 6 deletions

diff --git a/tests/codegen/array-cmp.rs b/tests/codegen/array-cmp.rs
index f9b7be89882..0d337655401 100644
--- a/tests/codegen/array-cmp.rs
+++ b/tests/codegen/array-cmp.rs
@@ -1,6 +1,7 @@
 // Ensure the asm for array comparisons is properly optimized.
 
 //@ compile-flags: -C opt-level=2
+//@ needs-deterministic-layouts (checks depend on tuple layout)
 
 #![crate_type = "lib"]
 
@@ -19,13 +20,55 @@ pub fn compare() -> bool {
 }
 
 // CHECK-LABEL: @array_of_tuple_le
-// CHECK: call{{.+}}i8 @llvm.scmp.i8.i16
-// CHECK: call{{.+}}i8 @llvm.ucmp.i8.i16
-// CHECK: call{{.+}}i8 @llvm.scmp.i8.i16
-// CHECK: call{{.+}}i8 @llvm.ucmp.i8.i16
-// CHECK: %[[RET:.+]] = icmp slt i8 {{.+}}, 1
-// CHECK: ret i8 %[[RET]]
 #[no_mangle]
 pub fn array_of_tuple_le(a: &[(i16, u16); 2], b: &[(i16, u16); 2]) -> bool {
+    // Ensure that, after all the optimizations have run, the happy path just checks
+    // `eq` on each corresponding pair and moves onto the next one if it is.
+    // Then there's a dedup'd comparison for the place that's different.
+    // (As opposed to, say, running a full `[su]cmp` as part of checking equality.)
+
+    // This is written quite specifically because different library code was triggering
+    // <https://github.com/llvm/llvm-project/issues/132678> along the way, so this
+    // has enough checks to make sure that's not happening. It doesn't need to be
+    // *exactly* this IR, but be careful if you ever need to update these checks.
+
+    // CHECK: start:
+    // CHECK: %[[A00:.+]] = load i16, ptr %a
+    // CHECK: %[[B00:.+]] = load i16, ptr %b
+    // CHECK-NOT: cmp
+    // CHECK: %[[EQ00:.+]] = icmp eq i16 %[[A00]], %[[B00]]
+    // CHECK-NEXT: br i1 %[[EQ00]], label %[[L01:.+]], label %[[EXIT_S:.+]]
+
+    // CHECK: [[L01]]:
+    // CHECK: %[[PA01:.+]] = getelementptr{{.+}}i8, ptr %a, {{i32|i64}} 2
+    // CHECK: %[[PB01:.+]] = getelementptr{{.+}}i8, ptr %b, {{i32|i64}} 2
+    // CHECK: %[[A01:.+]] = load i16, ptr %[[PA01]]
+    // CHECK: %[[B01:.+]] = load i16, ptr %[[PB01]]
+    // CHECK-NOT: cmp
+    // CHECK: %[[EQ01:.+]] = icmp eq i16 %[[A01]], %[[B01]]
+    // CHECK-NEXT: br i1 %[[EQ01]], label %[[L10:.+]], label %[[EXIT_U:.+]]
+
+    // CHECK: [[L10]]:
+    // CHECK: %[[PA10:.+]] = getelementptr{{.+}}i8, ptr %a, {{i32|i64}} 4
+    // CHECK: %[[PB10:.+]] = getelementptr{{.+}}i8, ptr %b, {{i32|i64}} 4
+    // CHECK: %[[A10:.+]] = load i16, ptr %[[PA10]]
+    // CHECK: %[[B10:.+]] = load i16, ptr %[[PB10]]
+    // CHECK-NOT: cmp
+    // CHECK: %[[EQ10:.+]] = icmp eq i16 %[[A10]], %[[B10]]
+    // CHECK-NEXT: br i1 %[[EQ10]], label %[[L11:.+]], label %[[EXIT_S]]
+
+    // CHECK: [[L11]]:
+    // CHECK: %[[PA11:.+]] = getelementptr{{.+}}i8, ptr %a, {{i32|i64}} 6
+    // CHECK: %[[PB11:.+]] = getelementptr{{.+}}i8, ptr %b, {{i32|i64}} 6
+    // CHECK: %[[A11:.+]] = load i16, ptr %[[PA11]]
+    // CHECK: %[[B11:.+]] = load i16, ptr %[[PB11]]
+    // CHECK-NOT: cmp
+    // CHECK: %[[EQ11:.+]] = icmp eq i16 %[[A11]], %[[B11]]
+    // CHECK-NEXT: br i1 %[[EQ11]], label %[[DONE:.+]], label %[[EXIT_U]]
+
+    // CHECK: [[DONE]]:
+    // CHECK: %[[RET:.+]] = phi i1 [ %{{.+}}, %[[EXIT_S]] ], [ %{{.+}}, %[[EXIT_U]] ], [ true, %[[L11]] ]
+    // CHECK: ret i1 %[[RET]]
+
     a <= b
 }