r174140 - Enable -fno-altivec, -mno-altivec for PowerPC.

[Bill Schmidt]

On Fri, 2013-02-01 at 04:48 +0200, Dmitri Gribenko wrote:
> On Fri, Feb 1, 2013 at 4:14 AM, Bill Schmidt
> <wschmidt at linux.vnet.ibm.com> wrote:
> > Author: wschmidt
> > Date: Thu Jan 31 20:14:03 2013
> > New Revision: 174140
> >
> > URL: http://llvm.org/viewvc/llvm-project?rev=174140&view=rev
> > Log:
> > Enable -fno-altivec, -mno-altivec for PowerPC.
> >
> > Introduces these negation forms explicitly and uses them to control a new
> > "altivec" target feature for PowerPC.  This allows avoiding generating
> > Altivec instructions on processors that support Altivec.
> >
> > The new test case verifies that the Altivec "lvx" instruction is not
> > used when -fno-altivec is present on the command line.
> >
> > Added:
> >     cfe/trunk/test/CodeGen/ppc-no-altivec.c
> > Modified:
> >     cfe/trunk/include/clang/Driver/Options.td
> >     cfe/trunk/lib/Basic/Targets.cpp
> >     cfe/trunk/lib/Driver/Tools.cpp
> >
> > Modified: cfe/trunk/include/clang/Driver/Options.td
> > URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/include/clang/Driver/Options.td?rev=174140&r1=174139&r2=174140&view=diff
> > ==============================================================================
> > --- cfe/trunk/include/clang/Driver/Options.td (original)
> > +++ cfe/trunk/include/clang/Driver/Options.td Thu Jan 31 20:14:03 2013
> > @@ -291,6 +291,7 @@ def faccess_control : Flag<["-"], "facce
> >  def fallow_unsupported : Flag<["-"], "fallow-unsupported">, Group<f_Group>;
> >  def faltivec : Flag<["-"], "faltivec">, Group<f_Group>, Flags<[CC1Option]>,
> >    HelpText<"Enable AltiVec vector initializer syntax">;
> > +def fno_altivec : Flag<["-"], "fno-altivec">, Group<f_Group>, Flags<[CC1Option]>;
> >  def fapple_kext : Flag<["-"], "fapple-kext">, Group<f_Group>, Flags<[CC1Option]>,
> >    HelpText<"Use Apple's kernel extensions ABI">;
> >  def fapple_pragma_pack : Flag<["-"], "fapple-pragma-pack">, Group<f_Group>, Flags<[CC1Option]>,
> > @@ -809,6 +810,7 @@ def m64 : Flag<["-"], "m64">, Group<m_Gr
> >  def mabi_EQ : Joined<["-"], "mabi=">, Group<m_Group>;
> >  def march_EQ : Joined<["-"], "march=">, Group<m_Group>;
> >  def maltivec : Flag<["-"], "maltivec">, Alias<faltivec>;
> > +def mno_altivec : Flag<["-"], "mno-altivec">, Alias<fno_altivec>;
> >  def mcmodel_EQ : Joined<["-"], "mcmodel=">, Group<m_Group>;
> >  def mconstant_cfstrings : Flag<["-"], "mconstant-cfstrings">, Group<clang_ignored_m_Group>;
> >  def mcpu_EQ : Joined<["-"], "mcpu=">, Group<m_Group>;
> >
> > Modified: cfe/trunk/lib/Basic/Targets.cpp
> > URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Basic/Targets.cpp?rev=174140&r1=174139&r2=174140&view=diff
> > ==============================================================================
> > --- cfe/trunk/lib/Basic/Targets.cpp (original)
> > +++ cfe/trunk/lib/Basic/Targets.cpp Thu Jan 31 20:14:03 2013
> > @@ -711,6 +711,12 @@ public:
> >    virtual void getTargetDefines(const LangOptions &Opts,
> >                                  MacroBuilder &Builder) const;
> >
> > +  virtual void getDefaultFeatures(llvm::StringMap<bool> &Features) const;
> > +
> > +  virtual bool setFeatureEnabled(llvm::StringMap<bool> &Features,
> > +                                 StringRef Name,
> > +                                 bool Enabled) const;
> > +
> >    virtual bool hasFeature(StringRef Feature) const;
> >
> >    virtual void getGCCRegNames(const char * const *&Names,
> > @@ -907,7 +913,32 @@ void PPCTargetInfo::getTargetDefines(con
> >    if (defs & ArchDefinePwr6) {
> >      Builder.defineMacro("_ARCH_PWR5");
> >      Builder.defineMacro("_ARCH_PWR6");
> > +  }
> > +}
> > +
> > +void PPCTargetInfo::getDefaultFeatures(llvm::StringMap<bool> &Features) const {
> > +  Features["altivec"] = llvm::StringSwitch<bool>(CPU)
> > +    .Case("7400", true)
> > +    .Case("g4", true)
> > +    .Case("7450", true)
> > +    .Case("g4+", true)
> > +    .Case("970", true)
> > +    .Case("g5", true)
> > +    .Case("pwr6", true)
> > +    .Case("pwr7", true)
> > +    .Case("ppc64", true)
> > +    .Default(false);
> > +}
> > +
> > +bool PPCTargetInfo::setFeatureEnabled(llvm::StringMap<bool> &Features,
> > +                                         StringRef Name,
> > +                                         bool Enabled) const {
> > +  if (Name == "altivec") {
> > +    Features[Name] = Enabled;
> > +    return true;
> >    }
> > +
> > +  return false;
> >  }
> >
> >  bool PPCTargetInfo::hasFeature(StringRef Feature) const {
> >
> > Modified: cfe/trunk/lib/Driver/Tools.cpp
> > URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Driver/Tools.cpp?rev=174140&r1=174139&r2=174140&view=diff
> > ==============================================================================
> > --- cfe/trunk/lib/Driver/Tools.cpp (original)
> > +++ cfe/trunk/lib/Driver/Tools.cpp Thu Jan 31 20:14:03 2013
> > @@ -1084,6 +1084,12 @@ void Clang::AddPPCTargetArgs(const ArgLi
> >      CmdArgs.push_back("-target-cpu");
> >      CmdArgs.push_back(Args.MakeArgString(TargetCPUName.c_str()));
> >    }
> > +
> > +  // Allow override of the Altivec feature.
> > +  if (Args.hasFlag(options::OPT_fno_altivec, options::OPT_faltivec, false)) {
> > +    CmdArgs.push_back("-target-feature");
> > +    CmdArgs.push_back("-altivec");
> > +  }
> >  }
> >
> >  void Clang::AddSparcTargetArgs(const ArgList &Args,
> >
> > Added: cfe/trunk/test/CodeGen/ppc-no-altivec.c
> > URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/CodeGen/ppc-no-altivec.c?rev=174140&view=auto
> > ==============================================================================
> > --- cfe/trunk/test/CodeGen/ppc-no-altivec.c (added)
> > +++ cfe/trunk/test/CodeGen/ppc-no-altivec.c Thu Jan 31 20:14:03 2013
> > @@ -0,0 +1,12 @@
> > +// REQUIRES: ppc64-registered-target
> > +// RUN: %clang_cc1 %s -triple=powerpc64-unknown-linux-gnu -S -o - | FileCheck %s
> > +
> > +typedef char v8qi  __attribute__((vector_size (8)));
> > +
> > +extern v8qi x, y;
> > +
> > +v8qi foo (void) {
> > +  return x + y;
> > +}
> > +
> > +// CHECK-NOT: lvx
> 
> Hi Bill,
> 
> In general, we avoid doing such end-to-end tests.  This change can be
> easily tested with a driver test.  I guess it should go into
> test/Driver/altivec.cpp, and you can get the idea from
> test/Driver/arm-mfpu.c.  Please add tests for different combinations
> of both flags.
> 
> You can also add tests for different CPUs (this is currently not
> tested, if I understand correctly).

Great, thanks for pointing me to this.  I wasn't aware of how to test
the output flags directly.  Much better.  I'll revise the tests as
suggested.

Bill
> 
> Dmitri
>