[clang] [HLSL] Add `InterlockedMax` function and resource methods (PR #222160)

[Finn Plummer via cfe-commits]

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@@ -0,0 +1,74 @@
+// RUN: %clang_cc1 -std=hlsl2021 -finclude-default-header -triple \
+// RUN:   dxil-pc-shadermodel6.6-library %s -emit-llvm -disable-llvm-passes -o - | \
+// RUN:   FileCheck %s --check-prefixes=CHECK,DXCHECK
+
+// RUN: %clang_cc1 -std=hlsl2021 -finclude-default-header -triple \
+// RUN:   spirv-pc-vulkan-library %s -emit-llvm -disable-llvm-passes -o - | \
+// RUN:   FileCheck %s --check-prefixes=CHECK,SPVCHECK
+
+// Test signed and unsigned lowering of HLSL InterlockedMax.
+
+groupshared int gs_i32;
+groupshared uint gs_u32;
+groupshared int64_t gs_i64;
+groupshared uint64_t gs_u64;
+
+// CHECK-LABEL: define {{.*}}void @{{.*}}test_int_2arg
----------------
inbelic wrote:

nit: the CHECK-LABEL pattern drifted from the file this test mirrors. `InterlockedMin.hlsl` uses

```
// CHECK-LABEL: define {{(dso_local |hidden |internal |protected |spir_func )*}}void @{{.*}}test_int_2arg
```
which we might want to remain consistent with one way or the other

https://github.com/llvm/llvm-project/pull/222160