Don't add multiple matrix layout options when creating a session (#6476)

The default matrix layout mode was applied in addition to any related options, and this
caused the wrong matrix layout mode to be used.
For example, tests/compute/column-major was failing when attempting to migrate to the new
compilation API.

This helps to address issue #4760

Author: aleino-nv

source/slang/slang.cpp

@@ -816,8 +816,6 @@ Session::createSession(slang::SessionDesc const& inDesc, slang::ISession** outSe
                 new TypeCheckingCache(*static_cast<TypeCheckingCache*>(m_typeCheckingCache.get()));
     }
 
-    linkage->setMatrixLayoutMode(desc.defaultMatrixLayoutMode);
-
     Int searchPathCount = desc.searchPathCount;
     for (Int ii = 0; ii < searchPathCount; ++ii)
     {
@@ -845,6 +843,10 @@ Session::createSession(slang::SessionDesc const& inDesc, slang::ISession** outSe
 
     linkage->m_optionSet.load(desc.compilerOptionEntryCount, desc.compilerOptionEntries);
 
+    if (!linkage->m_optionSet.hasOption(CompilerOptionName::MatrixLayoutColumn) &&
+        !linkage->m_optionSet.hasOption(CompilerOptionName::MatrixLayoutRow))
+        linkage->setMatrixLayoutMode(desc.defaultMatrixLayoutMode);
+
     {
         const Int targetCount = desc.targetCount;
         const uint8_t* targetDescPtr = reinterpret_cast<const uint8_t*>(desc.targets);