From 54ff7fd879e71f51ed3c0fda16224cbbcf0831eb Mon Sep 17 00:00:00 2001
From: kaizhangNV <149626564+kaizhangNV@users.noreply.github.com>
Date: Mon, 12 May 2025 15:32:25 -0500
Subject: Ensure to emit 32-bit type for bitfield operations for SPIRV (#7046)

Close #7014
---
 source/slang/slang-ir-spirv-legalize.cpp | 38 ++++++++++++++++++++++++++++++++
 1 file changed, 38 insertions(+)

(limited to 'source')

diff --git a/source/slang/slang-ir-spirv-legalize.cpp b/source/slang/slang-ir-spirv-legalize.cpp
index 82b424daa..0287ae81a 100644
--- a/source/slang/slang-ir-spirv-legalize.cpp
+++ b/source/slang/slang-ir-spirv-legalize.cpp
@@ -1471,6 +1471,39 @@ struct SPIRVLegalizationContext : public SourceEmitterBase
         }
     }
 
+    // TODO: Currently SPIRV doesn't support non-32-bit integer types for bitfield extract and
+    // insert. We will relax this restriction once this is done:
+    // https://github.com/shader-slang/slang/issues/7015.
+    void processBitFieldOp(IRInst* inst)
+    {
+        auto dataType = inst->getDataType();
+        IRVectorType* vectorType = as<IRVectorType>(dataType);
+        Slang::IRType* elementType = dataType;
+        if (vectorType)
+            elementType = vectorType->getElementType();
+
+        const IntInfo i = getIntTypeInfo(elementType);
+
+        // SPIRV doesn't support non-32bit integer types, so we need to convert
+        if (i.width < 32)
+        {
+            IRBuilder builder(inst);
+            builder.setInsertBefore(inst);
+            IRType* intType = i.isSigned ? builder.getIntType() : builder.getUIntType();
+            auto targetType = vectorType
+                                  ? builder.getVectorType(intType, vectorType->getElementCount())
+                                  : intType;
+            auto baseInst = builder.emitCast(targetType, inst->getOperand(0));
+            builder.replaceOperand(inst->getOperands(), baseInst);
+            if (inst->getOp() == kIROp_BitfieldInsert)
+            {
+                auto insertInst = builder.emitCast(targetType, inst->getOperand(1));
+                builder.replaceOperand(inst->getOperands() + 1, insertInst);
+            }
+            inst->setFullType(intType);
+        }
+    }
+
     void legalizeSPIRVEntryPoint(IRFunc* func, IREntryPointDecoration* entryPointDecor)
     {
         auto stage = entryPointDecor->getProfile().getStage();
@@ -1704,6 +1737,11 @@ struct SPIRVLegalizationContext : public SourceEmitterBase
             case kIROp_SPIRVAsm:
                 processSPIRVAsm(as<IRSPIRVAsm>(inst));
                 break;
+            case kIROp_BitfieldExtract:
+            case kIROp_BitfieldInsert:
+                processBitFieldOp(inst);
+                break;
+
             case kIROp_DebugValue:
                 if (!isSimpleDataType(as<IRDebugValue>(inst)->getDebugVar()->getDataType()))
                     inst->removeAndDeallocate();
-- 
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