[clang] [llvm] [DirectX] Remove trivially dead functions at linkage finalize (PR #106146)

[Joshua Batista via cfe-commits]

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@@ -0,0 +1,47 @@
+// RUN: %clang_cc1 -triple dxil-pc-shadermodel6.0-compute -S -o - %s | FileCheck %s
+// RUN: %clang_cc1 -triple dxil-pc-shadermodel6.3-library -S -o - %s | FileCheck %s
+
+// Verify that internal linkage unused functions are removed
+
+RWBuffer<unsigned> buf;
+
+// Never called functions should be removed.
+// CHECK-NOT: define{{.*}}uncalledFor
+void uncalledFor() {
+     buf[1] = 1;
+}
+
+// Never called but exported functions should remain.
+// CHECK: define void @"?exported@@YAXXZ"()
+export void exported() {
+     buf[1] = 1;
+}
+
+// Never called but noinlined functions should remain.
+// CHECK: define internal void @"?noinlined@@YAXXZ"()
+__attribute__((noinline)) void noinlined() {
+     buf[1] = 1;
+}
+
+// Called functions marked noinline should remain.
+// CHECK: define internal void @"?calledAndNoinlined@@YAXXZ"()
+__attribute__((noinline)) void calledAndNoinlined() {
+     buf[1] = 1;
+}
+
+// Called functions that get inlined by default should be removed.
+// CHECK-NOT: define{{.*}}calledAndInlined
+void calledAndInlined() {
+     buf[1] = 1;
+}
+
+
+// Entry point functions should remain.
+// CHECK: define{{.*}}main
+[numthreads(1,1,1)]
+[shader("compute")]
+void main() {
+     calledAndInlined();
+     calledAndNoinlined();
+     buf[0] = 0;
+}
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bob80905 wrote:

new line at EOF

https://github.com/llvm/llvm-project/pull/106146