[llvm] [HLSL] Fix detection of overlapping binding with unbounded array (PR #150547)

[Helena Kotas via llvm-commits]

https://github.com/hekota updated https://github.com/llvm/llvm-project/pull/150547

>From 6a515450001cb767512d158a0b53acb7040b43d3 Mon Sep 17 00:00:00 2001
From: Helena Kotas <hekotas at microsoft.com>
Date: Thu, 24 Jul 2025 16:26:26 -0700
Subject: [PATCH 1/2] [HLSL] Fix detection of overlapping binding with
 unbounded array

Fixes #150534
---
 llvm/include/llvm/Analysis/DXILResource.h     |  2 ++
 llvm/lib/Analysis/DXILResource.cpp            |  7 +++---
 .../DirectX/Binding/binding-overlap-6.ll      | 24 +++++++++++++++++++
 3 files changed, 30 insertions(+), 3 deletions(-)
 create mode 100644 llvm/test/CodeGen/DirectX/Binding/binding-overlap-6.ll

diff --git a/llvm/include/llvm/Analysis/DXILResource.h b/llvm/include/llvm/Analysis/DXILResource.h
index 9e2dc1ad771cf..956dcbcc33305 100644
--- a/llvm/include/llvm/Analysis/DXILResource.h
+++ b/llvm/include/llvm/Analysis/DXILResource.h
@@ -359,6 +359,8 @@ class ResourceInfo {
              std::tie(RHS.RecordID, RHS.Space, RHS.LowerBound, RHS.Size);
     }
     bool overlapsWith(const ResourceBinding &RHS) const {
+      if (Size == UINT32_MAX)
+        return LowerBound < RHS.LowerBound;
       return Space == RHS.Space && LowerBound + Size - 1 >= RHS.LowerBound;
     }
   };
diff --git a/llvm/lib/Analysis/DXILResource.cpp b/llvm/lib/Analysis/DXILResource.cpp
index 2da6468ec3dcf..179b7b4dc17f9 100644
--- a/llvm/lib/Analysis/DXILResource.cpp
+++ b/llvm/lib/Analysis/DXILResource.cpp
@@ -1079,15 +1079,16 @@ void DXILResourceBindingInfo::populate(Module &M, DXILResourceTypeMap &DRTM) {
       // add new space
       S = &BS->Spaces.emplace_back(B.Space);
 
-    // the space is full - set flag to report overlapping binding later
-    if (S->FreeRanges.empty()) {
+    // The space is full - there are no free slots left, or the rest of the
+    // slots are taken by an unbouded array. Set flag to report overlapping
+    // binding later.
+    if (S->FreeRanges.empty() || S->FreeRanges.back().UpperBound < UINT32_MAX) {
       OverlappingBinding = true;
       continue;
     }
 
     // adjust the last free range lower bound, split it in two, or remove it
     BindingRange &LastFreeRange = S->FreeRanges.back();
-    assert(LastFreeRange.UpperBound == UINT32_MAX);
     if (LastFreeRange.LowerBound == B.LowerBound) {
       if (B.UpperBound < UINT32_MAX)
         LastFreeRange.LowerBound = B.UpperBound + 1;
diff --git a/llvm/test/CodeGen/DirectX/Binding/binding-overlap-6.ll b/llvm/test/CodeGen/DirectX/Binding/binding-overlap-6.ll
new file mode 100644
index 0000000000000..3c37e639f0ede
--- /dev/null
+++ b/llvm/test/CodeGen/DirectX/Binding/binding-overlap-6.ll
@@ -0,0 +1,24 @@
+; RUN: not opt -S -passes='dxil-post-optimization-validation' -mtriple=dxil-pc-shadermodel6.3-library %s 2>&1 | FileCheck %s
+
+; Check overlap with unbounded array
+
+; A overlaps with B
+; RWBuffer<float> A[3] : register(u0);
+; RWBuffer<float> B[] : register(u4);
+; RWBuffer<float> C : register(u17);
+
+; CHECK: error: resource B at register 4 overlaps with resource C at register 17 in space 0
+
+target triple = "dxil-pc-shadermodel6.3-library"
+
+ at A.str = private unnamed_addr constant [2 x i8] c"A\00", align 1
+ at B.str = private unnamed_addr constant [2 x i8] c"B\00", align 1
+ at C.str = private unnamed_addr constant [2 x i8] c"C\00", align 1
+
+define void @test_overlapping() {
+entry:
+  %h1 = call target("dx.TypedBuffer", float, 1, 0, 0) @llvm.dx.resource.handlefrombinding(i32 0, i32 0, i32 3, i32 0, i1 false, ptr @A.str)
+  %h2 = call target("dx.TypedBuffer", float, 1, 0, 0) @llvm.dx.resource.handlefrombinding(i32 0, i32 4, i32 -1, i32 0, i1 false, ptr @B.str)
+  %h3 = call target("dx.TypedBuffer", float, 1, 0, 0) @llvm.dx.resource.handlefrombinding(i32 0, i32 17, i32 1, i32 0, i1 false, ptr @C.str)
+  ret void
+}

>From 54efe21eaf83257a5b5a7f94823da00c2b45a40c Mon Sep 17 00:00:00 2001
From: Helena Kotas <hekotas at microsoft.com>
Date: Thu, 24 Jul 2025 18:25:37 -0700
Subject: [PATCH 2/2] Update llvm/lib/Analysis/DXILResource.cpp

Co-authored-by: Justin Bogner <mail at justinbogner.com>
---
 llvm/lib/Analysis/DXILResource.cpp | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/llvm/lib/Analysis/DXILResource.cpp b/llvm/lib/Analysis/DXILResource.cpp
index 179b7b4dc17f9..1959ab6e510a3 100644
--- a/llvm/lib/Analysis/DXILResource.cpp
+++ b/llvm/lib/Analysis/DXILResource.cpp
@@ -1080,7 +1080,7 @@ void DXILResourceBindingInfo::populate(Module &M, DXILResourceTypeMap &DRTM) {
       S = &BS->Spaces.emplace_back(B.Space);
 
     // The space is full - there are no free slots left, or the rest of the
-    // slots are taken by an unbouded array. Set flag to report overlapping
+    // slots are taken by an unbounded array. Set flag to report overlapping
     // binding later.
     if (S->FreeRanges.empty() || S->FreeRanges.back().UpperBound < UINT32_MAX) {
       OverlappingBinding = true;