Fix C-style casts in GLSL pointer cast operations (#7841)

* Initial plan

* Fix C-style casts in GLSL pointer cast operations

Co-authored-by: csyonghe <2652293+csyonghe@users.noreply.github.com>

---------

Co-authored-by: copilot-swe-agent[bot] <198982749+Copilot@users.noreply.github.com>
Co-authored-by: csyonghe <2652293+csyonghe@users.noreply.github.com>

2 files changed, 31 insertions, 0 deletions

diff --git a/source/slang/slang-emit-glsl.cpp b/source/slang/slang-emit-glsl.cpp
index 9d4f72b07..eb71286a2 100644
--- a/source/slang/slang-emit-glsl.cpp
+++ b/source/slang/slang-emit-glsl.cpp
@@ -2727,6 +2727,23 @@ bool GLSLSourceEmitter::tryEmitInstExprImpl(IRInst* inst, const EmitOpInfo& inOu
             }
             break;
         }
+    case kIROp_CastPtrToInt:
+    case kIROp_CastIntToPtr:
+    case kIROp_PtrCast:
+        {
+            // For GLSL, emit constructor-style casts instead of C-style casts
+            auto prec = getInfo(EmitOp::Postfix);
+            EmitOpInfo outerPrec = inOuterPrec; // Make a mutable copy
+            bool needClose = maybeEmitParens(outerPrec, prec);
+
+            emitType(inst->getDataType());
+            m_writer->emit("(");
+            emitOperand(inst->getOperand(0), getInfo(EmitOp::General));
+            m_writer->emit(")");
+
+            maybeCloseParens(needClose);
+            return true;
+        }
     default:
         break;
     }
diff --git a/tests/language-feature/pointer-cast-glsl.slang b/tests/language-feature/pointer-cast-glsl.slang
new file mode 100644
index 000000000..9e51c4328
--- /dev/null
+++ b/tests/language-feature/pointer-cast-glsl.slang
@@ -0,0 +1,14 @@
+//TEST:SIMPLE(filecheck=GLSL):-target glsl -entry main
+
+// Test that pointer casts in GLSL generate constructor-style casts instead of C-style casts
+// This addresses issue https://github.com/shader-slang/slang/issues/7838
+
+//GLSL: BufferPointer__S1_2(address_0)
+
+[shader("vertex")]
+float4 main(uint vertexID : SV_VertexID, uint64_t address) : SV_Position
+{
+    // This should generate BufferPointer(address) instead of (BufferPointer)address in GLSL
+    let buffer = ConstBufferPointer<float4>(address);
+    return buffer[vertexID];
+}
\ No newline at end of file