[clang] [HLSL] set alwaysinline on HLSL functions (PR #106588)

[Damyan Pepper via cfe-commits]

================
@@ -0,0 +1,114 @@
+// RUN: %clang_cc1 -x hlsl -triple  dxil-pc-shadermodel6.3-library %s -emit-llvm -disable-llvm-passes -o - | FileCheck %s --check-prefixes=CHECK,NOINLINE
+// RUN: %clang_cc1 -x hlsl -triple  dxil-pc-shadermodel6.3-library %s -emit-llvm -O0 -o - | FileCheck %s --check-prefixes=CHECK,INLINE
+// RUN: %clang_cc1 -x hlsl -triple  dxil-pc-shadermodel6.0-compute %s -emit-llvm -disable-llvm-passes -o - | FileCheck %s --check-prefixes=CHECK,NOINLINE
+// RUN: %clang_cc1 -x hlsl -triple  dxil-pc-shadermodel6.0-compute %s -emit-llvm -O0 -o - | FileCheck %s --check-prefixes=CHECK,INLINE
+
+// Tests that user functions will always be inlined.
+// This includes exported functions and mangled entry point implementation functions.
+// The unmangled entry functions must not be alwaysinlined.
+
+#define MAX 100
+
+float nums[MAX];
+
+// Verify that all functions have the alwaysinline attribute
+// CHECK: Function Attrs: alwaysinline
+// CHECK: define void @"?swap@@YAXY0GE at III@Z"(ptr noundef byval([100 x i32]) align 4 %Buf, i32 noundef %ix1, i32 noundef %ix2) [[IntAttr:\#[0-9]+]]
----------------
damyanp wrote:

(probably a learning opportunity for me:)

Wondering why the define is still expected here. I would have expected it to not appear because it got inlined. 

https://github.com/llvm/llvm-project/pull/106588