Patch for LowerSwitchPass

This change is to address a crash in findNearestCommonDominator called in the CodeSinking pass.
The reason for removing unreachable blocks is this change in the LLVM repo:
llvm/llvm-project@1065f34
LowerSwitchPass can leave phi instructions with nodes from unreachable basic blocks
which is a disallowed state for DomTree.

Author: krystian-andrzejewski

external/llvm/releases/14.0.0/patches_external/LowerSwitch-RemoveUnreachableBBs.patch

@@ -0,0 +1,42 @@
+/*========================== begin_copyright_notice ============================
+
+Copyright (C) 2024 Intel Corporation
+
+SPDX-License-Identifier: MIT
+
+============================= end_copyright_notice ===========================*/
+/*========================== begin_copyright_notice ============================
+
+Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+See https://llvm.org/LICENSE.txt for license information.
+SPDX-License-Identifier: Apache-2.0 with LLVM-exception
+
+============================= end_copyright_notice ===========================*/
+The reason for removing unreachable blocks is this change in the LLVM repo:
+https://github.com/llvm/llvm-project/commit/1065f3439bad59323f16e7c8ee568c7d94dcd952
+LowerSwitchPass can leave phi instructions with nodes from unreachable basic blocks
+which is a disallowed state for DomTree.
+
+diff --git a/llvm/lib/Transforms/Utils/LowerSwitch.cpp b/llvm/lib/Transforms/Utils/LowerSwitch.cpp
+index aff9d1311..b38de0a7a 100644
+--- a/llvm/lib/Transforms/Utils/LowerSwitch.cpp
++++ b/llvm/lib/Transforms/Utils/LowerSwitch.cpp
+@@ -38,6 +38,7 @@
+ #include "llvm/Support/raw_ostream.h"
+ #include "llvm/Transforms/Utils.h"
+ #include "llvm/Transforms/Utils/BasicBlockUtils.h"
++#include "llvm/Transforms/Utils/Local.h"
+ #include <algorithm>
+ #include <cassert>
+ #include <cstdint>
+@@ -542,6 +543,10 @@ bool LowerSwitch(Function &F, LazyValueInfo *LVI, AssumptionCache *AC) {
+     DeleteDeadBlock(BB);
+   }
+ 
++  if (!DeleteList.empty()) {
++    removeUnreachableBlocks(F);
++  }
++
+   return Changed;
+ }
+ 

external/llvm/releases/15.0.0/patches_external/LowerSwitch-RemoveUnreachableBBs.patch

@@ -0,0 +1,42 @@
+/*========================== begin_copyright_notice ============================
+
+Copyright (C) 2024 Intel Corporation
+
+SPDX-License-Identifier: MIT
+
+============================= end_copyright_notice ===========================*/
+/*========================== begin_copyright_notice ============================
+
+Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+See https://llvm.org/LICENSE.txt for license information.
+SPDX-License-Identifier: Apache-2.0 with LLVM-exception
+
+============================= end_copyright_notice ===========================*/
+The reason for removing unreachable blocks is this change in the LLVM repo:
+https://github.com/llvm/llvm-project/commit/1065f3439bad59323f16e7c8ee568c7d94dcd952
+LowerSwitchPass can leave phi instructions with nodes from unreachable basic blocks
+which is a disallowed state for DomTree.
+
+diff --git a/llvm/lib/Transforms/Utils/LowerSwitch.cpp b/llvm/lib/Transforms/Utils/LowerSwitch.cpp
+index aff9d1311..b38de0a7a 100644
+--- a/llvm/lib/Transforms/Utils/LowerSwitch.cpp
++++ b/llvm/lib/Transforms/Utils/LowerSwitch.cpp
+@@ -38,6 +38,7 @@
+ #include "llvm/Support/raw_ostream.h"
+ #include "llvm/Transforms/Utils.h"
+ #include "llvm/Transforms/Utils/BasicBlockUtils.h"
++#include "llvm/Transforms/Utils/Local.h"
+ #include <algorithm>
+ #include <cassert>
+ #include <cstdint>
+@@ -542,6 +543,10 @@ bool LowerSwitch(Function &F, LazyValueInfo *LVI, AssumptionCache *AC) {
+     DeleteDeadBlock(BB);
+   }
+ 
++  if (!DeleteList.empty()) {
++    removeUnreachableBlocks(F);
++  }
++
+   return Changed;
+ }
+