[clang] [llvm] [DXIL] Remove incompatible metadata types when preparing DXIL. (PR #136386)

[Justin Bogner via cfe-commits]

================
@@ -0,0 +1,39 @@
+; RUN: opt -S --dxil-prepare %s | FileCheck %s
+
+; This test tests the whitelist inside of DxilPrepare.cpp.
+; It ensures that certain metadata nodes are removed that aren't
+; in the whitelist, and that certain nodes may remain that
+; are on the whitelist.
+
+target triple = "dxilv1.0-unknown-shadermodel6.0-compute"
+
+; Function Attrs: noinline nounwind memory(readwrite, inaccessiblemem: none)
+define void @main(i32* %ptr) {
+entry:  
+  ; metadata ID changes to 0 once the current !0 and !1 are removed
+  ; since they aren't in the whitelist. range needs a payload.
+  ; CHECK: %val = load i32, ptr %ptr, align 4, !range !0
+  %val = load i32, ptr %ptr, align 4, !range !2
+
+  ; dx.nonuniform is a valid metadata node kind on the whitelist,
+  ; so give it a bogus payload and ensure it sticks around
+  ; CHECK-next: %cmp.i1.not = icmp eq i32 1, 0, !dx.nonuniform !0
+  %cmp.i1.not = icmp eq i32 1, 0, !dx.nonuniform !2
----------------
bogner wrote:

Probably better to either get an instruction with a valid payload here or omit this one - the check that `!range` gets through probably proves that we're hitting this codepath well enough

https://github.com/llvm/llvm-project/pull/136386