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Add a new -fmerge-functions -cc1 flag that enables function merging. 

llvm-svn: 220543
This commit is contained in:
Nick Lewycky 2014-10-24 00:49:29 +00:00
parent f4c504e03c
commit f04f237e0c
5 changed files with 19 additions and 0 deletions
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2
clang/include/clang/Driver/CC1Options.td
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@ -169,6 +169,8 @@ def no_implicit_float : Flag<["-"], "no-implicit-float">,
HelpText<"Don't generate implicit floating point instructions">;
def fdump_vtable_layouts : Flag<["-"], "fdump-vtable-layouts">,
HelpText<"Dump the layouts of all vtables that will be emitted in a translation unit">;
def fmerge_functions : Flag<["-"], "fmerge-functions">,
HelpText<"Permit merging of identical functions when optimizing.">;
def femit_coverage_notes : Flag<["-"], "femit-coverage-notes">,
HelpText<"Emit a gcov coverage notes file when compiling.">;
def femit_coverage_data: Flag<["-"], "femit-coverage-data">,

1
clang/include/clang/Frontend/CodeGenOptions.def
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@ -67,6 +67,7 @@ CODEGENOPT(InstrumentForProfiling , 1, 0) ///< Set when -pg is enabled.
CODEGENOPT(LessPreciseFPMAD , 1, 0) ///< Enable less precise MAD instructions to
///< be generated.
CODEGENOPT(MergeAllConstants , 1, 1) ///< Merge identical constants.
CODEGENOPT(MergeFunctions , 1, 0) ///< Set when -fmerge-functions is enabled.
CODEGENOPT(NoCommon , 1, 0) ///< Set when -fno-common or C++ is enabled.
CODEGENOPT(NoDwarfDirectoryAsm , 1, 0) ///< Set when -fno-dwarf-directory-asm is
///< enabled.

1
clang/lib/CodeGen/BackendUtil.cpp
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@ -247,6 +247,7 @@ void EmitAssemblyHelper::CreatePasses() {
PMBuilder.DisableTailCalls = CodeGenOpts.DisableTailCalls;
PMBuilder.DisableUnitAtATime = !CodeGenOpts.UnitAtATime;
PMBuilder.DisableUnrollLoops = !CodeGenOpts.UnrollLoops;
PMBuilder.MergeFunctions = CodeGenOpts.MergeFunctions;
PMBuilder.RerollLoops = CodeGenOpts.RerollLoops;
PMBuilder.addExtension(PassManagerBuilder::EP_EarlyAsPossible,

1
clang/lib/Frontend/CompilerInvocation.cpp
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@ -452,6 +452,7 @@ static bool ParseCodeGenArgs(CodeGenOptions &Opts, ArgList &Args, InputKind IK,
OPT_fno_function_sections, false);
Opts.DataSections = Args.hasFlag(OPT_fdata_sections,
OPT_fno_data_sections, false);
Opts.MergeFunctions = Args.hasArg(OPT_fmerge_functions);
Opts.VectorizeBB = Args.hasArg(OPT_vectorize_slp_aggressive);
Opts.VectorizeLoop = Args.hasArg(OPT_vectorize_loops);

14
clang/test/CodeGenCXX/merge-functions.cpp Normal file
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@ -0,0 +1,14 @@
// REQUIRES: x86-registered-target
// RUN: %clang_cc1 -triple x86_64-pc-linux-gnu -O1 -fmerge-functions -emit-llvm -o - -x c++ < %s | FileCheck %s
// Basic functionality test. Function merging doesn't kick in on functions that
// are too simple.
struct A {
virtual int f(int x, int *p) { return x ? *p : 1; }
virtual int g(int x, int *p) { return x ? *p : 1; }
} a;
// CHECK: define {{.*}} @_ZN1A1gEiPi
// CHECK-NEXT: tail call i32 @_ZN1A1fEiPi
// CHECK-NEXT: ret