From eb3970897049269602cc18cee644e437c0aff928 Mon Sep 17 00:00:00 2001
From: Yong He <yonghe@outlook.com>
Date: Tue, 7 May 2024 21:50:41 -0700
Subject: Make sure pointer local vars have `AliasedPointer` decoration.
 (#4132)

---
 source/slang/slang-emit-spirv.cpp | 19 +++++++++++++++++++
 tests/bugs/gh-4111.slang          | 31 +++++++++++++++++++++++++++++++
 2 files changed, 50 insertions(+)
 create mode 100644 tests/bugs/gh-4111.slang

diff --git a/source/slang/slang-emit-spirv.cpp b/source/slang/slang-emit-spirv.cpp
index a7cdfc8a3..8219d3534 100644
--- a/source/slang/slang-emit-spirv.cpp
+++ b/source/slang/slang-emit-spirv.cpp
@@ -4077,6 +4077,8 @@ struct SPIRVEmitContext
             return;
         if (ptrType->getAddressSpace() == SpvStorageClassPhysicalStorageBuffer)
         {
+            // If inst has a pointer type with PhysicalStorageBuffer address space,
+            // emit AliasedPointer decoration.
             emitOpDecorate(
                 getSection(SpvLogicalSectionID::Annotations),
                 nullptr,
@@ -4084,6 +4086,23 @@ struct SPIRVEmitContext
                 (as<IRVar>(inst) ? SpvDecorationAliasedPointer : SpvDecorationAliased)
             );
         }
+        else
+        {
+            // If the pointee type is a pointer with StorageBuffer address space,
+            // we also want to emit AliasedPointer decoration.
+            ptrType = as<IRPtrType>(ptrType->getValueType());
+            if (!ptrType)
+                return;
+            if (ptrType->getAddressSpace() == SpvStorageClassPhysicalStorageBuffer)
+            {
+                emitOpDecorate(
+                    getSection(SpvLogicalSectionID::Annotations),
+                    nullptr,
+                    varInst,
+                    (as<IRVar>(inst) ? SpvDecorationAliasedPointer : SpvDecorationAliased)
+                );
+            }
+        }
     }
 
     SpvInst* emitParam(SpvInstParent* parent, IRInst* inst)
diff --git a/tests/bugs/gh-4111.slang b/tests/bugs/gh-4111.slang
new file mode 100644
index 000000000..66d565d9f
--- /dev/null
+++ b/tests/bugs/gh-4111.slang
@@ -0,0 +1,31 @@
+//TEST:SIMPLE(filecheck=CHECK): -target spirv
+
+// Check that a pointer typed local variable has `AliasedPointer` decoration.
+
+// CHECK: OpDecorate %b AliasedPointer
+struct Buf
+{
+    uint test;
+};
+
+struct Push
+{
+    bool a_or_b;
+    Buf * a;
+    Buf * b;
+};
+
+[[vk::push_constant]] Push push;
+
+func tester(Buf * buf)
+{
+    buf->test = 1;
+}
+
+[shader("compute")]
+[numthreads(1, 1, 1)]
+void main()
+{
+    Buf * b = push.a_or_b ? push.a : push.b;
+    tester(b);
+}
\ No newline at end of file
-- 
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