[llvm] 44ffeec - [DXIL][Analysis] Make sure resource accessors are contiguous (#128696)

[via llvm-commits]

Author: Justin Bogner
Date: 2025-02-25T13:52:17-08:00
New Revision: 44ffeecde2658249d57a54f52c11a339f2e6d14e

URL: https://github.com/llvm/llvm-project/commit/44ffeecde2658249d57a54f52c11a339f2e6d14e
DIFF: https://github.com/llvm/llvm-project/commit/44ffeecde2658249d57a54f52c11a339f2e6d14e.diff

LOG: [DXIL][Analysis] Make sure resource accessors are contiguous (#128696)

When some resource types were present, but not all of them, we were
ending up in a situation where we would fail to initialize the `FirstX`
variables and get incorrect iterators.

Fixes #128560.

Added: 
    llvm/test/CodeGen/DirectX/Metadata/cbuffer-only.ll

Modified: 
    llvm/lib/Analysis/DXILResource.cpp

Removed: 
    


################################################################################
diff  --git a/llvm/lib/Analysis/DXILResource.cpp b/llvm/lib/Analysis/DXILResource.cpp
index c0319c9a354a6..22afb4cba6f26 100644
--- a/llvm/lib/Analysis/DXILResource.cpp
+++ b/llvm/lib/Analysis/DXILResource.cpp
@@ -756,6 +756,11 @@ void DXILBindingMap::populate(Module &M, DXILResourceTypeMap &DRTM) {
       NextID = 0;
     }
 
+    // We need to make sure the types of resource are ordered even if some are
+    // missing.
+    FirstCBuffer = std::min({FirstCBuffer, FirstSampler});
+    FirstUAV = std::min({FirstUAV, FirstCBuffer});
+
     // Adjust the resource binding to use the next ID.
     RBI.setBindingID(NextID++);
   }

diff  --git a/llvm/test/CodeGen/DirectX/Metadata/cbuffer-only.ll b/llvm/test/CodeGen/DirectX/Metadata/cbuffer-only.ll
new file mode 100644
index 0000000000000..c07e8d9a2b591
--- /dev/null
+++ b/llvm/test/CodeGen/DirectX/Metadata/cbuffer-only.ll
@@ -0,0 +1,19 @@
+; Regression test for https://github.com/llvm/llvm-project/issues/128560 -
+; check that cbuffers are populated correctly when there aren't any other kinds
+; of resource.
+
+; RUN: opt -S -passes=dxil-translate-metadata %s | FileCheck %s
+
+target triple = "dxil-pc-shadermodel6.6-compute"
+
+define void @cbuffer_is_only_binding() {
+  %cbuf = call target("dx.CBuffer", target("dx.Layout", {float}, 4, 0))
+      @llvm.dx.resource.handlefrombinding(i32 1, i32 8, i32 1, i32 0, i1 false)
+  ; CHECK: %cbuffer = type
+
+  ret void
+}
+
+; CHECK:      @[[CB0:.*]] = external constant %cbuffer
+
+; CHECK: !{i32 0, ptr @[[CB0]], !""