Universally run GVN, even when there aren't multiple basic blocks

Universally run GVN, even when there aren't multiple basic blocks

Author: jaladreips

IGC/Compiler/CISACodeGen/ShaderCodeGen.cpp

@@ -1293,6 +1293,10 @@ void OptimizeIR(CodeGenContext *const pContext) {
     }
     mpm.add(new BlockMemOpAddrScalarizationPass());
 
+    if (IGC_IS_FLAG_ENABLED(EnableGVN)) {
+      mpm.add(llvm::createGVNPass());
+    }
+
     if (pContext->m_instrTypes.hasMultipleBB && !disableGOPT) {
       if (pContext->m_instrTypes.numOfLoop) {
         bool allowLICM = IGC_IS_FLAG_ENABLED(allowLICM) && pContext->m_retryManager.AllowLICM();