[llvm-branch-commits] [llvm] [DirectX] Add DXIL validation of `llvm.loop` metadata (PR #164292)

[Helena Kotas via llvm-branch-commits]

================
@@ -0,0 +1,58 @@
+; RUN: split-file %s %t
+; RUN: opt -S --dxil-translate-metadata %t/not-distinct.ll 2>&1 | FileCheck %t/not-distinct.ll
+; RUN: opt -S --dxil-translate-metadata %t/not-md.ll 2>&1 | FileCheck %t/not-md.ll
+
+; Test that DXIL incompatible loop metadata is stripped
+
+;--- not-distinct.ll
+
+; Ensure it is stripped because it is not provided a distinct loop parent
+; CHECK-NOT: {!"llvm.loop.unroll.disable"}
+
+target triple = "dxilv1.0-unknown-shadermodel6.0-library"
+
+define void @example_loop(i32 %n) {
+entry:
+  br label %loop.header
+
+loop.header:
+  %i = phi i32 [ 0, %entry ], [ %i.next, %loop.body ]
+  %cmp = icmp slt i32 %i, %n
+  br i1 %cmp, label %loop.body, label %exit
+
+loop.body:
+  %i.next = add nsw i32 %i, 1
+  br label %loop.header, !llvm.loop !1
+
+exit:
+  ret void
+}
+
+!1 = !{!"llvm.loop.unroll.disable"} ; first node must be a distinct self-reference
+
+
+;--- not-md.ll
+
+target triple = "dxilv1.0-unknown-shadermodel6.0-library"
+
+define void @example_loop(i32 %n) {
+entry:
+  br label %loop.header
+
+loop.header:
+  %i = phi i32 [ 0, %entry ], [ %i.next, %loop.body ]
+  %cmp = icmp slt i32 %i, %n
+  br i1 %cmp, label %loop.body, label %exit
+
+loop.body:
+  %i.next = add nsw i32 %i, 1
+  ; CHECK: br label %loop.header, !llvm.loop ![[#LOOP_MD:]]
+  br label %loop.header, !llvm.loop !1
+
+exit:
+  ret void
+}
+
+; CHECK: ![[#LOOP_MD:]] = distinct !{![[#LOOP_MD]]}
+
+!1 = !{!1, i32 0} ; not a metadata node
----------------
hekota wrote:

```suggestion
!1 = !{!1, i32 0} ; second operand is not a metadata node
```

https://github.com/llvm/llvm-project/pull/164292