jrtc27 updated this revision to Diff 362214.
jrtc27 added a comment.
Now only a CC1 option
Repository:
rG LLVM Github Monorepo
CHANGES SINCE LAST ACTION
https://reviews.llvm.org/D105516/new/
https://reviews.llvm.org/D105516
Files:
clang/include/clang/Basic/CodeGenOptions.def
clang/include/clang/Driver/Options.td
clang/lib/CodeGen/BackendUtil.cpp
clang/lib/CodeGen/CodeGenModule.cpp
clang/test/CodeGen/falways-mem2reg.c
llvm/include/llvm/Passes/PassBuilder.h
llvm/include/llvm/Transforms/IPO/PassManagerBuilder.h
llvm/lib/Passes/PassBuilder.cpp
llvm/lib/Transforms/IPO/PassManagerBuilder.cpp
Index: llvm/lib/Transforms/IPO/PassManagerBuilder.cpp
===================================================================
--- llvm/lib/Transforms/IPO/PassManagerBuilder.cpp
+++ llvm/lib/Transforms/IPO/PassManagerBuilder.cpp
@@ -187,6 +187,7 @@
LibraryInfo = nullptr;
Inliner = nullptr;
DisableUnrollLoops = false;
+ AlwaysMem2Reg = false;
SLPVectorize = false;
LoopVectorize = true;
LoopsInterleaved = true;
@@ -658,8 +659,11 @@
MPM.add(createForceFunctionAttrsLegacyPass());
// If all optimizations are disabled, just run the always-inline pass and,
- // if enabled, the function merging pass.
+ // if enabled, the mem2reg and function merging passes.
if (OptLevel == 0) {
+ if (AlwaysMem2Reg)
+ MPM.add(createPromoteMemoryToRegisterPass());
+
addPGOInstrPasses(MPM);
if (Inliner) {
MPM.add(Inliner);
Index: llvm/lib/Passes/PassBuilder.cpp
===================================================================
--- llvm/lib/Passes/PassBuilder.cpp
+++ llvm/lib/Passes/PassBuilder.cpp
@@ -283,6 +283,7 @@
SLPVectorization = false;
LoopUnrolling = true;
ForgetAllSCEVInLoopUnroll = ForgetSCEVInLoopUnroll;
+ AlwaysMem2Reg = false;
Coroutines = false;
LicmMssaOptCap = SetLicmMssaOptCap;
LicmMssaNoAccForPromotionCap = SetLicmMssaNoAccForPromotionCap;
@@ -1931,6 +1932,9 @@
MPM.addPass(AlwaysInlinerPass(
/*InsertLifetimeIntrinsics=*/PTO.Coroutines));
+ if (PTO.AlwaysMem2Reg)
+ MPM.addPass(createModuleToFunctionPassAdaptor(PromotePass()));
+
if (PTO.MergeFunctions)
MPM.addPass(MergeFunctionsPass());
Index: llvm/include/llvm/Transforms/IPO/PassManagerBuilder.h
===================================================================
--- llvm/include/llvm/Transforms/IPO/PassManagerBuilder.h
+++ llvm/include/llvm/Transforms/IPO/PassManagerBuilder.h
@@ -156,6 +156,7 @@
bool DisableTailCalls;
bool DisableUnrollLoops;
+ bool AlwaysMem2Reg;
bool CallGraphProfile;
bool SLPVectorize;
bool LoopVectorize;
Index: llvm/include/llvm/Passes/PassBuilder.h
===================================================================
--- llvm/include/llvm/Passes/PassBuilder.h
+++ llvm/include/llvm/Passes/PassBuilder.h
@@ -107,6 +107,10 @@
/// is that of the flag: `-forget-scev-loop-unroll`.
bool ForgetAllSCEVInLoopUnroll;
+ /// Tuning option to always run mem2reg regardless of the optimisation level.
+ /// Its default value is false.
+ bool AlwaysMem2Reg;
+
/// Tuning option to enable/disable coroutine intrinsic lowering. Its default
/// value is false. Frontends such as Clang may enable this conditionally. For
/// example, Clang enables this option if the flags `-std=c++2a` or above, or
Index: clang/test/CodeGen/falways-mem2reg.c
===================================================================
--- /dev/null
+++ clang/test/CodeGen/falways-mem2reg.c
@@ -0,0 +1,33 @@
+// NOTE: Assertions have been autogenerated by utils/update_cc_test_checks.py
+// RUN: %clang_cc1 -triple riscv64 -emit-llvm -o - -flegacy-pass-manager -O0 %s \
+// RUN: | FileCheck --check-prefix=O0-NO-MEM2REG %s
+// RUN: %clang_cc1 -triple riscv64 -emit-llvm -o - -fno-legacy-pass-manager -O0 %s \
+// RUN: | FileCheck --check-prefix=O0-NO-MEM2REG %s
+// RUN: %clang_cc1 -triple riscv64 -emit-llvm -o - -flegacy-pass-manager -O0 -fno-always-mem2reg %s \
+// RUN: | FileCheck --check-prefix=O0-NO-MEM2REG %s
+// RUN: %clang_cc1 -triple riscv64 -emit-llvm -o - -fno-legacy-pass-manager -O0 -fno-always-mem2reg %s \
+// RUN: | FileCheck --check-prefix=O0-NO-MEM2REG %s
+// RUN: %clang_cc1 -triple riscv64 -emit-llvm -o - -flegacy-pass-manager -O0 -falways-mem2reg %s \
+// RUN: | FileCheck --check-prefix=O0-MEM2REG %s
+// RUN: %clang_cc1 -triple riscv64 -emit-llvm -o - -fno-legacy-pass-manager -O0 -falways-mem2reg %s \
+// RUN: | FileCheck --check-prefix=O0-MEM2REG %s
+
+// O0-NO-MEM2REG-LABEL: @add(
+// O0-NO-MEM2REG-NEXT: entry:
+// O0-NO-MEM2REG-NEXT: [[A_ADDR:%.*]] = alloca i32, align 4
+// O0-NO-MEM2REG-NEXT: [[B_ADDR:%.*]] = alloca i32, align 4
+// O0-NO-MEM2REG-NEXT: store i32 [[A:%.*]], i32* [[A_ADDR]], align 4
+// O0-NO-MEM2REG-NEXT: store i32 [[B:%.*]], i32* [[B_ADDR]], align 4
+// O0-NO-MEM2REG-NEXT: [[TMP0:%.*]] = load i32, i32* [[A_ADDR]], align 4
+// O0-NO-MEM2REG-NEXT: [[TMP1:%.*]] = load i32, i32* [[B_ADDR]], align 4
+// O0-NO-MEM2REG-NEXT: [[ADD:%.*]] = add nsw i32 [[TMP0]], [[TMP1]]
+// O0-NO-MEM2REG-NEXT: ret i32 [[ADD]]
+//
+// O0-MEM2REG-LABEL: @add(
+// O0-MEM2REG-NEXT: entry:
+// O0-MEM2REG-NEXT: [[ADD:%.*]] = add nsw i32 [[A:%.*]], [[B:%.*]]
+// O0-MEM2REG-NEXT: ret i32 [[ADD]]
+//
+int add(int a, int b) {
+ return a + b;
+}
Index: clang/lib/CodeGen/CodeGenModule.cpp
===================================================================
--- clang/lib/CodeGen/CodeGenModule.cpp
+++ clang/lib/CodeGen/CodeGenModule.cpp
@@ -1764,6 +1764,8 @@
// starting with the default for this optimization level.
bool ShouldAddOptNone =
!CodeGenOpts.DisableO0ImplyOptNone && CodeGenOpts.OptimizationLevel == 0;
+ // -falways-mem2reg implies at least a minimal amount of optimisation.
+ ShouldAddOptNone &= !CodeGenOpts.AlwaysMem2Reg;
// We can't add optnone in the following cases, it won't pass the verifier.
ShouldAddOptNone &= !D->hasAttr<MinSizeAttr>();
ShouldAddOptNone &= !D->hasAttr<AlwaysInlineAttr>();
Index: clang/lib/CodeGen/BackendUtil.cpp
===================================================================
--- clang/lib/CodeGen/BackendUtil.cpp
+++ clang/lib/CodeGen/BackendUtil.cpp
@@ -682,6 +682,7 @@
PMBuilder.CallGraphProfile = !CodeGenOpts.DisableIntegratedAS;
PMBuilder.DisableUnrollLoops = !CodeGenOpts.UnrollLoops;
+ PMBuilder.AlwaysMem2Reg = CodeGenOpts.AlwaysMem2Reg;
// Loop interleaving in the loop vectorizer has historically been set to be
// enabled when loop unrolling is enabled.
PMBuilder.LoopsInterleaved = CodeGenOpts.UnrollLoops;
@@ -1256,6 +1257,7 @@
PTO.LoopInterleaving = CodeGenOpts.UnrollLoops;
PTO.LoopVectorization = CodeGenOpts.VectorizeLoop;
PTO.SLPVectorization = CodeGenOpts.VectorizeSLP;
+ PTO.AlwaysMem2Reg = CodeGenOpts.AlwaysMem2Reg;
PTO.MergeFunctions = CodeGenOpts.MergeFunctions;
// Only enable CGProfilePass when using integrated assembler, since
// non-integrated assemblers don't recognize .cgprofile section.
Index: clang/include/clang/Driver/Options.td
===================================================================
--- clang/include/clang/Driver/Options.td
+++ clang/include/clang/Driver/Options.td
@@ -4788,6 +4788,10 @@
MarshallingInfoFlag<LangOpts<"NoMathBuiltin">>;
def fuse_ctor_homing: Flag<["-"], "fuse-ctor-homing">,
HelpText<"Use constructor homing if we are using limited debug info already">;
+defm falways_mem2reg : BoolFOption<"always-mem2reg",
+ CodeGenOpts<"AlwaysMem2Reg">, DefaultFalse,
+ PosFlag<SetTrue, [], "Always run mem2reg regardless of optimisation level">,
+ NegFlag<SetFalse, [], "Run mem2reg based on optimisation level">>;
}
def disable_llvm_verifier : Flag<["-"], "disable-llvm-verifier">,
Index: clang/include/clang/Basic/CodeGenOptions.def
===================================================================
--- clang/include/clang/Basic/CodeGenOptions.def
+++ clang/include/clang/Basic/CodeGenOptions.def
@@ -270,6 +270,7 @@
CODEGENOPT(UnrollLoops , 1, 0) ///< Control whether loops are unrolled.
CODEGENOPT(RerollLoops , 1, 0) ///< Control whether loops are rerolled.
CODEGENOPT(NoUseJumpTables , 1, 0) ///< Set when -fno-jump-tables is enabled.
+CODEGENOPT(AlwaysMem2Reg , 1, 0) ///< Set when -falways-mem2reg is enabled.
CODEGENOPT(UnwindTables , 1, 0) ///< Emit unwind tables.
CODEGENOPT(VectorizeLoop , 1, 0) ///< Run loop vectorizer.
CODEGENOPT(VectorizeSLP , 1, 0) ///< Run SLP vectorizer.
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