https://github.com/erichkeane updated https://github.com/llvm/llvm-project/pull/222201
>From 91a6f188abe06810f2722c7e116e584ccce88bd5 Mon Sep 17 00:00:00 2001 From: erichkeane <[email protected]> Date: Tue, 8 Sep 2026 16:15:46 -0700 Subject: [PATCH 1/4] [CIR] Enable PCH Build- A very simple PCH file that seems to gain us about 3% on build time. On my personal build (with a bunch of our other optimizations) it goes from: real: 7m58 -->7m42 user: 612m53-->585m18 sys: 36m27 -->34m57 I suspect there are more gains to be had by adding other files here, but this improvement seems worth doing. --- clang/lib/CIR/CodeGen/CMakeLists.txt | 4 ++++ clang/lib/CIR/CodeGen/pch.h | 23 +++++++++++++++++++ clang/lib/CIR/Dialect/CMakeLists.txt | 7 +++++- clang/lib/CIR/Dialect/IR/CMakeLists.txt | 7 ++++++ .../lib/CIR/Dialect/Transforms/CMakeLists.txt | 4 ++++ clang/lib/CIR/Dialect/Transforms/pch.h | 20 ++++++++++++++++ 6 files changed, 64 insertions(+), 1 deletion(-) create mode 100644 clang/lib/CIR/CodeGen/pch.h create mode 100644 clang/lib/CIR/Dialect/Transforms/pch.h diff --git a/clang/lib/CIR/CodeGen/CMakeLists.txt b/clang/lib/CIR/CodeGen/CMakeLists.txt index c4bd520fc61b7..3992f7c476b03 100644 --- a/clang/lib/CIR/CodeGen/CMakeLists.txt +++ b/clang/lib/CIR/CodeGen/CMakeLists.txt @@ -64,6 +64,10 @@ add_clang_library(clangCIR MLIRCIR MLIRCIROpInterfacesIncGen + DISABLE_PCH_REUSE # PCH contains private headers + PRECOMPILE_HEADERS + [["pch.h"]] + LINK_LIBS clangAST clangBasic diff --git a/clang/lib/CIR/CodeGen/pch.h b/clang/lib/CIR/CodeGen/pch.h new file mode 100644 index 0000000000000..dca5bc15ce0e6 --- /dev/null +++ b/clang/lib/CIR/CodeGen/pch.h @@ -0,0 +1,23 @@ +//===----------------------------------------------------------------------===// +// +// 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 +// +//===----------------------------------------------------------------------===// +/// +/// Precompiled header for clangCIR. Uses private headers. +/// +//===----------------------------------------------------------------------===// + +#include "Address.h" +#include "CIRGenBuilder.h" +#include "CIRGenCXXABI.h" +#include "CIRGenFunction.h" +#include "CIRGenModule.h" +#include "CIRGenValue.h" +#include "mlir/Dialect/OpenACC/OpenACC.h" +#include "mlir/Dialect/OpenMP/OpenMPDialect.h" +#include "mlir/Dialect/Ptr/IR/MemorySpaceInterfaces.h" +#include "clang/AST/pch.h" +#include "llvm/Support/pch.h" diff --git a/clang/lib/CIR/Dialect/CMakeLists.txt b/clang/lib/CIR/Dialect/CMakeLists.txt index 6aacd029d845d..8ddfd544cbe44 100644 --- a/clang/lib/CIR/Dialect/CMakeLists.txt +++ b/clang/lib/CIR/Dialect/CMakeLists.txt @@ -1,5 +1,10 @@ -add_subdirectory(Analysis) +# IR must be processed first: it defines MLIRCIR, whose PCH other CIR +# dialect libraries below (Analysis, OpenACC, OpenMP, Transforms) can +# automatically reuse via llvm_update_pch's LLVM_PCH_PRIORITY dependency +# scan -- that scan only sees targets that already exist, so MLIRCIR must +# be defined before anything that wants to reuse its PCH. add_subdirectory(IR) +add_subdirectory(Analysis) add_subdirectory(OpenACC) add_subdirectory(OpenMP) add_subdirectory(Transforms) diff --git a/clang/lib/CIR/Dialect/IR/CMakeLists.txt b/clang/lib/CIR/Dialect/IR/CMakeLists.txt index c8205ebeabf6c..c5fa438253460 100644 --- a/clang/lib/CIR/Dialect/IR/CMakeLists.txt +++ b/clang/lib/CIR/Dialect/IR/CMakeLists.txt @@ -13,6 +13,13 @@ add_clang_library(MLIRCIR MLIRCIROpInterfacesIncGen MLIRCIRLoopOpInterfaceIncGen + # CIRDialect.h is a public header and the most commonly-included header + # across the rest of clang/lib/CIR; building it here (rather than as a + # private per-library PCH) lets every other CIR library that links + # MLIRCIR automatically reuse this PCH too. + PRECOMPILE_HEADERS + [["clang/CIR/Dialect/IR/CIRDialect.h"]] + LINK_LIBS PUBLIC MLIRIR MLIRCIRInterfaces diff --git a/clang/lib/CIR/Dialect/Transforms/CMakeLists.txt b/clang/lib/CIR/Dialect/Transforms/CMakeLists.txt index 82078bf2e8f73..7208537642507 100644 --- a/clang/lib/CIR/Dialect/Transforms/CMakeLists.txt +++ b/clang/lib/CIR/Dialect/Transforms/CMakeLists.txt @@ -18,6 +18,10 @@ add_clang_library(MLIRCIRTransforms DEPENDS MLIRCIRPassIncGen + DISABLE_PCH_REUSE # PCH contains private headers + PRECOMPILE_HEADERS + [["pch.h"]] + LINK_LIBS PUBLIC clangAST clangBasic diff --git a/clang/lib/CIR/Dialect/Transforms/pch.h b/clang/lib/CIR/Dialect/Transforms/pch.h new file mode 100644 index 0000000000000..df51a30d01e92 --- /dev/null +++ b/clang/lib/CIR/Dialect/Transforms/pch.h @@ -0,0 +1,20 @@ +//===----------------------------------------------------------------------===// +// +// 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 +// +//===----------------------------------------------------------------------===// +/// +/// Precompiled header for MLIRCIRTransforms. Uses private headers. +/// +//===----------------------------------------------------------------------===// + +#include "PassDetail.h" +#include "clang/CIR/Dialect/Builder/CIRBaseBuilder.h" +#include "clang/CIR/Dialect/IR/CIRDialect.h" +#include "clang/CIR/Dialect/Passes.h" +#include "clang/CIR/Dialect/Transforms/CIRTransformUtils.h" +#include "clang/CIR/MissingFeatures.h" +#include "mlir/IR/PatternMatch.h" +#include "mlir/Transforms/DialectConversion.h" >From 31b7015b11a5d06335bef0aa10d639d82b4ed033 Mon Sep 17 00:00:00 2001 From: erichkeane <[email protected]> Date: Tue, 8 Sep 2026 17:08:27 -0700 Subject: [PATCH 2/4] Clang-format --- clang/lib/CIR/Dialect/Transforms/pch.h | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/clang/lib/CIR/Dialect/Transforms/pch.h b/clang/lib/CIR/Dialect/Transforms/pch.h index df51a30d01e92..c5b8938ac86a1 100644 --- a/clang/lib/CIR/Dialect/Transforms/pch.h +++ b/clang/lib/CIR/Dialect/Transforms/pch.h @@ -11,10 +11,10 @@ //===----------------------------------------------------------------------===// #include "PassDetail.h" +#include "mlir/IR/PatternMatch.h" +#include "mlir/Transforms/DialectConversion.h" #include "clang/CIR/Dialect/Builder/CIRBaseBuilder.h" #include "clang/CIR/Dialect/IR/CIRDialect.h" #include "clang/CIR/Dialect/Passes.h" #include "clang/CIR/Dialect/Transforms/CIRTransformUtils.h" #include "clang/CIR/MissingFeatures.h" -#include "mlir/IR/PatternMatch.h" -#include "mlir/Transforms/DialectConversion.h" >From 82cd50c74a2e4740ece360db5afd61a2aeac599e Mon Sep 17 00:00:00 2001 From: erichkeane <[email protected]> Date: Tue, 8 Sep 2026 17:48:47 -0700 Subject: [PATCH 3/4] Remove MemorySpaceInterfaces.h since it is transitively included by Address.h --- clang/lib/CIR/CodeGen/pch.h | 1 - 1 file changed, 1 deletion(-) diff --git a/clang/lib/CIR/CodeGen/pch.h b/clang/lib/CIR/CodeGen/pch.h index dca5bc15ce0e6..732397ec5ad1d 100644 --- a/clang/lib/CIR/CodeGen/pch.h +++ b/clang/lib/CIR/CodeGen/pch.h @@ -18,6 +18,5 @@ #include "CIRGenValue.h" #include "mlir/Dialect/OpenACC/OpenACC.h" #include "mlir/Dialect/OpenMP/OpenMPDialect.h" -#include "mlir/Dialect/Ptr/IR/MemorySpaceInterfaces.h" #include "clang/AST/pch.h" #include "llvm/Support/pch.h" >From 632159027ba8f1dd60792c344fbd81a0086cdcae Mon Sep 17 00:00:00 2001 From: erichkeane <[email protected]> Date: Tue, 8 Sep 2026 17:54:44 -0700 Subject: [PATCH 4/4] Add a few more pch uses, this time in TargetLowering, which gives a partial percent improvement --- .../Transforms/TargetLowering/CMakeLists.txt | 4 ++++ .../CIR/Dialect/Transforms/TargetLowering/pch.h | 15 +++++++++++++++ 2 files changed, 19 insertions(+) create mode 100644 clang/lib/CIR/Dialect/Transforms/TargetLowering/pch.h diff --git a/clang/lib/CIR/Dialect/Transforms/TargetLowering/CMakeLists.txt b/clang/lib/CIR/Dialect/Transforms/TargetLowering/CMakeLists.txt index 81cc336699391..87f2842d7df67 100644 --- a/clang/lib/CIR/Dialect/Transforms/TargetLowering/CMakeLists.txt +++ b/clang/lib/CIR/Dialect/Transforms/TargetLowering/CMakeLists.txt @@ -11,6 +11,10 @@ add_clang_library(MLIRCIRTargetLowering DEPENDS clangBasic + DISABLE_PCH_REUSE # PCH contains private headers + PRECOMPILE_HEADERS + [["pch.h"]] + LINK_COMPONENTS TargetParser diff --git a/clang/lib/CIR/Dialect/Transforms/TargetLowering/pch.h b/clang/lib/CIR/Dialect/Transforms/TargetLowering/pch.h new file mode 100644 index 0000000000000..edef2a22aec49 --- /dev/null +++ b/clang/lib/CIR/Dialect/Transforms/TargetLowering/pch.h @@ -0,0 +1,15 @@ +//===----------------------------------------------------------------------===// +// +// 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 +// +//===----------------------------------------------------------------------===// +/// +/// Precompiled header for MLIRCIRTargetLowering. Uses private headers. +/// +//===----------------------------------------------------------------------===// + +#include "CIRCXXABI.h" +#include "LowerModule.h" +#include "TargetLoweringInfo.h" _______________________________________________ cfe-commits mailing list [email protected] https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
