Disable NewPM by default

This also reverts commit 59ecd8783b36e1ba2b42e020d46456329554f107,
which is directly related to default pass manager type.

Author: vmaksimo

clang/test/CodeGenSYCL/kernel-early-optimization-pipeline.cpp

@@ -1,12 +1,10 @@
 // Check LLVM optimization pipeline is run by default for SPIR-V compiled for
 // SYCL device target, and can be disabled with -fno-sycl-early-optimizations.
 //
-// RUN: %clang_cc1 -O2 -fsycl -fsycl-is-device -triple spir64-unknown-unknown-sycldevice %s -fdebug-pass-manager -emit-llvm -o - 2>&1 | FileCheck %s --check-prefix=CHECK-EARLYOPT
-// CHECK-EARLYOPT: Starting llvm::Module pass manager run.
-// CHECK-EARLYOPT: Running pass: GlobalOptPass
-// CHECK-EARLYOPT: Running pass: GlobalDCEPass
-// CHECK-EARLYOPT: Running pass: PrintModulePass on
+// RUN: %clang_cc1 -O2 -fsycl -fsycl-is-device -triple spir64-unknown-unknown-sycldevice %s -mllvm -debug-pass=Structure -emit-llvm -o - 2>&1 | FileCheck %s --check-prefix=CHECK-EARLYOPT
+// CHECK-EARLYOPT: Lower Work Group Scope Code
+// CHECK-EARLYOPT: Combine redundant instructions
 //
-// RUN: %clang_cc1 -O2 -fsycl -fsycl-is-device -fno-sycl-early-optimizations -triple spir64-unknown-unknown-sycldevice %s -fdebug-pass-manager -emit-llvm -o - 2>&1 | FileCheck %s --check-prefix=CHECK-NOEARLYOPT
-// CHECK-NOEARLYOPT: Starting llvm::Module pass manager run.
-// CHECK-NOEARLYOPT-NEXT: Running pass: PrintModulePass on
+// RUN: %clang_cc1 -O2 -fsycl -fsycl-is-device -fno-sycl-early-optimizations -triple spir64-unknown-unknown-sycldevice %s -mllvm -debug-pass=Structure -emit-llvm -o - 2>&1 | FileCheck %s --check-prefix=CHECK-NOEARLYOPT
+// CHECK-NOEARLYOPT: Lower Work Group Scope Code
+// CHECK-NOEARLYOPT-NOT: Combine redundant instructions

llvm/CMakeLists.txt

@@ -694,7 +694,7 @@ else()
 endif()
 option(LLVM_ENABLE_PLUGINS "Enable plugin support" ${LLVM_ENABLE_PLUGINS_default})
 
-set(ENABLE_EXPERIMENTAL_NEW_PASS_MANAGER TRUE CACHE BOOL
+set(ENABLE_EXPERIMENTAL_NEW_PASS_MANAGER FALSE CACHE BOOL
   "Enable the new pass manager by default.")
 
 include(HandleLLVMOptions)