Add case to `emitVectorReshape` for when using a `vector<M, N>` type with `T` value (#4419)

* Add case to `emitVectorReshape` for `vector<>` type, `scalar` value

1. Add new case
2. Add test

* fix warning

* fix warning

2 files changed, 39 insertions, 1 deletions

diff --git a/source/slang/slang-ir.cpp b/source/slang/slang-ir.cpp
index 22ef4e6be..c0541f4c4 100644
--- a/source/slang/slang-ir.cpp
+++ b/source/slang/slang-ir.cpp
@@ -3894,7 +3894,23 @@ namespace Slang
     {
         auto targetVectorType = as<IRVectorType>(type);
         auto sourceVectorType = as<IRVectorType>(value->getDataType());
-        if (!targetVectorType)
+        if (targetVectorType && !sourceVectorType)
+        {
+            auto elementType = targetVectorType->getElementType();
+            Index elemCount = 1;
+            if(auto intLit = as<IRIntLit>(targetVectorType->getElementCount()))
+            {
+                elemCount = (Index)intLit->getValue();
+            }
+            IRInst* zeroVal = emitDefaultConstruct(elementType);
+            List<IRInst*> defaultVals;
+            defaultVals.reserve(elemCount);
+            defaultVals.add(value);
+            for(auto i = 1; i < elemCount; i++)
+                defaultVals.add(zeroVal);
+            return emitMakeVector(targetVectorType, defaultVals);
+        }
+        else if (!targetVectorType)
         {
             if (!sourceVectorType)
                 return emitCast(targetVectorType, value);
diff --git a/tests/bugs/gh-4411.slang b/tests/bugs/gh-4411.slang
new file mode 100644
index 000000000..06adff0b3
--- /dev/null
+++ b/tests/bugs/gh-4411.slang
@@ -0,0 +1,22 @@
+//TEST(compute, vulkan):COMPARE_COMPUTE_EX(filecheck-buffer=BUF):-vk -compute -shaderobj
+//TEST(compute):COMPARE_COMPUTE_EX(filecheck-buffer=BUF):-slang -compute -dx12 -use-dxil -shaderobj
+
+//TEST_INPUT:RWTexture1D(format=R32_UINT, size=8, content = zero, mipMaps = 1):name=texture1D
+RWTexture1D<uint> texture1D;
+
+//TEST_INPUT:RWTexture2D(format=R32_UINT, size=8, content = zero, mipMaps = 1):name=texture2D
+RWTexture2D<uint> texture2D;
+
+//TEST_INPUT:ubuffer(data=[0]):out,name=outputBuffer
+RWStructuredBuffer<uint> outputBuffer;
+
+void computeMain() {
+    texture1D[1].x = 15;
+    texture2D[uint2(2, 3)].x = 16;
+
+    outputBuffer[0] = uint(true
+            && texture1D[1].x == 15
+            && texture2D[uint2(2, 3)].x == 16
+        );
+    //BUF: 1
+}
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