[X86] Support CFE flags for APX features (llvm#74199)

Positive options: -mapx-features=<comma-separated-features>
Negative options: -mno-apx-features=<comma-separated-features>

-m[no-]apx-features is designed to be able to control separate APX
features.

Besides, we also support the flag -m[no-]apxf, which can be used like an
alias of -m[no-]apx-features=< all APX features covered by CPUID APX_F>

Behaviour when positive and negative options are used together:

For boolean flags, the last one wins

-mapxf   -mno-apxf   -> -mno-apxf
-mno-apxf   -mapxf   -> -mapxf

For flags that take a set as arguments, it sets the mask by order of the
flags

-mapx-features=egpr,ndd  -mno-apx-features=egpr  ->   -egpr,+ndd
-mapx-features=egpr  -mno-apx-features=egpr,ndd  ->   -egpr,-ndd
-mno-apx-features=egpr  -mapx-features=egpr,ndd  ->   +egpr,+ndd
-mno-apx-features=egpr,ndd  -mapx-features=egpr  ->   -ndd,+egpr

The design is aligned with gcc
https://gcc.gnu.org/pipermail/gcc-patches/2023-August/628905.html

clang/include/clang/Driver/Options.td

@@ -5999,6 +5999,15 @@ def mno_gather : Flag<["-"], "mno-gather">, Group<m_Group>,
                  HelpText<"Disable generation of gather instructions in auto-vectorization(x86 only)">;
 def mno_scatter : Flag<["-"], "mno-scatter">, Group<m_Group>,
                   HelpText<"Disable generation of scatter instructions in auto-vectorization(x86 only)">;
+def mapx_features_EQ : CommaJoined<["-"], "mapx-features=">, Group<m_x86_Features_Group>,
+    HelpText<"Enable features of APX">, Values<"egpr,push2pop2,ppx,ndd,ccmp,cf">;
+def mno_apx_features_EQ : CommaJoined<["-"], "mno-apx-features=">, Group<m_x86_Features_Group>,
+    HelpText<"Disable features of APX">, Values<"egpr,push2pop2,ppx,ndd,ccmp,cf">;
+// Features egpr, push2pop2 and ppx are validated with llvm-test-suite && cpu2017 on Intel SDE.
+// For stability, we turn on these features only for -mapxf. After a feature pass the validation,
+// we will add it to -mapxf.
+def mapxf : Flag<["-"], "mapxf">, Alias<mapx_features_EQ>, AliasArgs<["egpr","push2pop2","ppx"]>;
+def mno_apxf : Flag<["-"], "mno-apxf">, Alias<mno_apx_features_EQ>, AliasArgs<["egpr","push2pop2","ppx"]>;
 } // let Flags = [TargetSpecific]
 
 // VE feature flags

clang/lib/Basic/Targets/X86.cpp

@@ -428,6 +428,18 @@ bool X86TargetInfo::handleTargetFeatures(std::vector<std::string> &Features,
       HasX87 = true;
     } else if (Feature == "+fullbf16") {
       HasFullBFloat16 = true;
+    } else if (Feature == "+egpr") {
+      HasEGPR = true;
+    } else if (Feature == "+push2pop2") {
+      HasPush2Pop2 = true;
+    } else if (Feature == "+ppx") {
+      HasPPX = true;
+    } else if (Feature == "+ndd") {
+      HasNDD = true;
+    } else if (Feature == "+ccmp") {
+      HasCCMP = true;
+    } else if (Feature == "+cf") {
+      HasCF = true;
     }
 
     X86SSEEnum Level = llvm::StringSwitch<X86SSEEnum>(Feature)
@@ -927,6 +939,18 @@ void X86TargetInfo::getTargetDefines(const LangOptions &Opts,
     Builder.defineMacro("__USERMSR__");
   if (HasCRC32)
     Builder.defineMacro("__CRC32__");
+  if (HasEGPR)
+    Builder.defineMacro("__EGPR__");
+  if (HasPush2Pop2)
+    Builder.defineMacro("__PUSH2POP2__");
+  if (HasPPX)
+    Builder.defineMacro("__PPX__");
+  if (HasNDD)
+    Builder.defineMacro("__NDD__");
+  if (HasCCMP)
+    Builder.defineMacro("__CCMP__");
+  if (HasCF)
+    Builder.defineMacro("__CF__");
 
   // Each case falls through to the previous one here.
   switch (SSELevel) {
@@ -1122,6 +1146,12 @@ bool X86TargetInfo::isValidFeatureName(StringRef Name) const {
       .Case("xsavec", true)
       .Case("xsaves", true)
       .Case("xsaveopt", true)
+      .Case("egpr", true)
+      .Case("push2pop2", true)
+      .Case("ppx", true)
+      .Case("ndd", true)
+      .Case("ccmp", true)
+      .Case("cf", true)
       .Default(false);
 }
 
@@ -1238,6 +1268,12 @@ bool X86TargetInfo::hasFeature(StringRef Feature) const {
       .Case("xsaves", HasXSAVES)
       .Case("xsaveopt", HasXSAVEOPT)
       .Case("fullbf16", HasFullBFloat16)
+      .Case("egpr", HasEGPR)
+      .Case("push2pop2", HasPush2Pop2)
+      .Case("ppx", HasPPX)
+      .Case("ndd", HasNDD)
+      .Case("ccmp", HasCCMP)
+      .Case("cf", HasCF)
       .Default(false);
 }
 

clang/lib/Basic/Targets/X86.h

@@ -168,6 +168,12 @@ class LLVM_LIBRARY_VISIBILITY X86TargetInfo : public TargetInfo {
   bool HasUINTR = false;
   bool HasCRC32 = false;
   bool HasX87 = false;
+  bool HasEGPR = false;
+  bool HasPush2Pop2 = false;
+  bool HasPPX = false;
+  bool HasNDD = false;
+  bool HasCCMP = false;
+  bool HasCF = false;
 
 protected:
   llvm::X86::CPUKind CPU = llvm::X86::CK_None;

clang/lib/Driver/ToolChains/Arch/X86.cpp

@@ -270,6 +270,21 @@ void x86::getX86TargetFeatures(const Driver &D, const llvm::Triple &Triple,
     }
 
     bool IsNegative = Name.startswith("no-");
+    if (A->getOption().matches(options::OPT_mapx_features_EQ) ||
+        A->getOption().matches(options::OPT_mno_apx_features_EQ)) {
+
+      for (StringRef Value : A->getValues()) {
+        if (Value == "egpr" || Value == "push2pop2" || Value == "ppx" ||
+            Value == "ndd" || Value == "ccmp" || Value == "cf") {
+          Features.push_back(
+              Args.MakeArgString((IsNegative ? "-" : "+") + Value));
+          continue;
+        }
+        D.Diag(clang::diag::err_drv_unsupported_option_argument)
+            << A->getSpelling() << Value;
+      }
+      continue;
+    }
     if (IsNegative)
       Name = Name.substr(3);
     Features.push_back(Args.MakeArgString((IsNegative ? "-" : "+") + Name));

clang/test/Driver/x86-target-features.c

@@ -422,3 +422,42 @@
 
 // RUN: touch %t.o
 // RUN: %clang -fdriver-only -Werror --target=x86_64-pc-linux-gnu -mharden-sls=all %t.o -o /dev/null 2>&1 | count 0
+
+// RUN: %clang -target x86_64-unknown-linux-gnu -mapxf %s -### -o %t.o 2>&1 | FileCheck -check-prefix=APXF %s
+// RUN: %clang -target x86_64-unknown-linux-gnu -mno-apxf %s -### -o %t.o 2>&1 | FileCheck -check-prefix=NO-APXF %s
+// RUN: %clang -target x86_64-unknown-linux-gnu -mno-apxf -mapxf %s -### -o %t.o 2>&1 | FileCheck -check-prefix=APXF %s
+// RUN: %clang -target x86_64-unknown-linux-gnu -mapxf -mno-apxf %s -### -o %t.o 2>&1 | FileCheck -check-prefix=NO-APXF %s
+//
+// APXF: "-target-feature" "+egpr" "-target-feature" "+push2pop2" "-target-feature" "+ppx"
+// NO-APXF: "-target-feature" "-egpr" "-target-feature" "-push2pop2" "-target-feature" "-ppx"
+
+// RUN: %clang -target x86_64-unknown-linux-gnu -mapx-features=egpr %s -### -o %t.o 2>&1 | FileCheck -check-prefix=EGPR %s
+// RUN: %clang -target x86_64-unknown-linux-gnu -mapx-features=push2pop2 %s -### -o %t.o 2>&1 | FileCheck -check-prefix=PUSH2POP2 %s
+// RUN: %clang -target x86_64-unknown-linux-gnu -mapx-features=ppx %s -### -o %t.o 2>&1 | FileCheck -check-prefix=PPX %s
+// RUN: %clang -target x86_64-unknown-linux-gnu -mapx-features=ndd %s -### -o %t.o 2>&1 | FileCheck -check-prefix=NDD %s
+// RUN: %clang -target x86_64-unknown-linux-gnu -mapx-features=ccmp %s -### -o %t.o 2>&1 | FileCheck -check-prefix=CCMP %s
+// RUN: %clang -target x86_64-unknown-linux-gnu -mapx-features=cf %s -### -o %t.o 2>&1 | FileCheck -check-prefix=CF %s
+// EGPR: "-target-feature" "+egpr"
+// PUSH2POP2: "-target-feature" "+push2pop2"
+// PPX: "-target-feature" "+ppx"
+// NDD: "-target-feature" "+ndd"
+// CCMP: "-target-feature" "+ccmp"
+// CF: "-target-feature" "+cf"
+
+// RUN: %clang -target x86_64-unknown-linux-gnu -mapx-features=egpr,ndd %s -### -o %t.o 2>&1 | FileCheck -check-prefix=EGPR-NDD %s
+// RUN: %clang -target x86_64-unknown-linux-gnu -mapx-features=egpr -mapx-features=ndd %s -### -o %t.o 2>&1 | FileCheck -check-prefix=EGPR-NDD %s
+// RUN: %clang -target x86_64-unknown-linux-gnu -mno-apx-features=egpr -mno-apx-features=ndd %s -### -o %t.o 2>&1 | FileCheck -check-prefix=NO-EGPR-NO-NDD %s
+// RUN: %clang -target x86_64-unknown-linux-gnu -mno-apx-features=egpr -mapx-features=egpr,ndd %s -### -o %t.o 2>&1 | FileCheck -check-prefix=EGPR-NDD %s
+// RUN: %clang -target x86_64-unknown-linux-gnu -mno-apx-features=egpr,ndd -mapx-features=egpr %s -### -o %t.o 2>&1 | FileCheck -check-prefix=EGPR-NO-NDD %s
+// RUN: %clang -target x86_64-unknown-linux-gnu -mapx-features=egpr,ndd -mno-apx-features=egpr %s -### -o %t.o 2>&1 | FileCheck -check-prefix=NO-EGPR-NDD %s
+// RUN: %clang -target x86_64-unknown-linux-gnu -mapx-features=egpr -mno-apx-features=egpr,ndd %s -### -o %t.o 2>&1 | FileCheck -check-prefix=NO-EGPR-NO-NDD %s
+//
+// EGPR-NDD: "-target-feature" "+egpr" "-target-feature" "+ndd"
+// EGPR-NO-NDD: "-target-feature" "-ndd" "-target-feature" "+egpr"
+// NO-EGPR-NDD: "-target-feature" "+ndd" "-target-feature" "-egpr"
+// NO-EGPR-NO-NDD: "-target-feature" "-egpr" "-target-feature" "-ndd"
+
+// RUN: not %clang -target x86_64-unknown-linux-gnu -mapx-features=egpr,foo,bar %s -### -o %t.o 2>&1 | FileCheck -check-prefix=ERROR %s
+//
+// ERROR: unsupported argument 'foo' to option '-mapx-features='
+// ERROR: unsupported argument 'bar' to option '-mapx-features='

clang/test/Preprocessor/x86_target_features.c

@@ -796,3 +796,17 @@
 // RUN: %clang -target i386-unknown-linux-gnu -march=i386 -mno-rdpru -x c -E -dM -o - %s | FileCheck -check-prefix=NORDPRU %s
 
 // NORDPRU-NOT: #define __RDPRU__ 1
+
+// RUN: %clang -target x86_64-unknown-unknown -march=x86-64 -mapx-features=egpr -x c -E -dM -o - %s | FileCheck --check-prefix=EGPR %s
+// RUN: %clang -target x86_64-unknown-unknown -march=x86-64 -mapx-features=push2pop2 -x c -E -dM -o - %s | FileCheck --check-prefix=PUSH2POP2 %s
+// RUN: %clang -target x86_64-unknown-unknown -march=x86-64 -mapx-features=ppx -x c -E -dM -o - %s | FileCheck --check-prefix=PPX %s
+// RUN: %clang -target x86_64-unknown-unknown -march=x86-64 -mapx-features=ndd -x c -E -dM -o - %s | FileCheck --check-prefix=NDD %s
+// RUN: %clang -target x86_64-unknown-unknown -march=x86-64 -mapx-features=ccmp -x c -E -dM -o - %s | FileCheck --check-prefix=CCMP %s
+// RUN: %clang -target x86_64-unknown-unknown -march=x86-64 -mapx-features=cf -x c -E -dM -o - %s | FileCheck --check-prefix=CF %s
+// RUN: %clang -target x86_64-unknown-unknown -march=x86-64 -mapxf -x c -E -dM -o - %s | FileCheck --check-prefixes=EGPR,PUSH2POP2,PPX %s
+// EGPR: #define __EGPR__ 1
+// PPX: #define __PPX__ 1
+// PUSH2POP2: #define __PUSH2POP2__ 1
+// NDD: #define __NDD__ 1
+// CCMP: #define __CCMP__ 1
+// CF: #define __CF__ 1

llvm/docs/ReleaseNotes.rst

@@ -156,6 +156,7 @@ Changes to the X86 Backend
 * Support ISA of ``USER_MSR``.
 * Support ISA of ``AVX10.1-256`` and ``AVX10.1-512``.
 * ``-mcpu=pantherlake`` and ``-mcpu=clearwaterforest`` are now supported.
+* ``-mapxf`` is supported.
 
 Changes to the OCaml bindings
 -----------------------------

llvm/include/llvm/TargetParser/X86TargetParser.def

@@ -246,6 +246,12 @@ X86_FEATURE       (EVEX512,         "evex512")
 X86_FEATURE       (AVX10_1,         "avx10.1-256")
 X86_FEATURE       (AVX10_1_512,     "avx10.1-512")
 X86_FEATURE       (USERMSR,         "usermsr")
+X86_FEATURE       (EGPR,            "egpr")
+X86_FEATURE       (Push2Pop2,       "push2pop2")
+X86_FEATURE       (PPX,             "ppx")
+X86_FEATURE       (NDD,             "ndd")
+X86_FEATURE       (CCMP,            "ccmp")
+X86_FEATURE       (CF,              "cf")
 // These features aren't really CPU features, but the frontend can set them.
 X86_FEATURE       (RETPOLINE_EXTERNAL_THUNK,    "retpoline-external-thunk")
 X86_FEATURE       (RETPOLINE_INDIRECT_BRANCHES, "retpoline-indirect-branches")

llvm/lib/Target/X86/X86.td

@@ -347,6 +347,12 @@ def FeaturePush2Pop2 : SubtargetFeature<"push2pop2", "HasPush2Pop2", "true",
                                         "Support PUSH2/POP2 instructions">;
 def FeaturePPX : SubtargetFeature<"ppx", "HasPPX", "true",
                                   "Support Push-Pop Acceleration">;
+def FeatureNDD : SubtargetFeature<"ndd", "HasNDD", "true",
+                                  "Support non-destructive destination">;
+def FeatureCCMP : SubtargetFeature<"ccmp", "HasCCMP", "true",
+                                   "Support conditional cmp & test instructions">;
+def FeatureCF : SubtargetFeature<"cf", "HasCF", "true",
+                                 "Support conditional faulting">;
 
 // Ivy Bridge and newer processors have enhanced REP MOVSB and STOSB (aka
 // "string operations"). See "REP String Enhancement" in the Intel Software

llvm/lib/TargetParser/X86TargetParser.cpp

@@ -628,6 +628,14 @@ constexpr FeatureBitset ImpliedFeaturesAVX10_1 =
 constexpr FeatureBitset ImpliedFeaturesAVX10_1_512 =
     FeatureAVX10_1 | FeatureEVEX512;
 
+// APX Features
+constexpr FeatureBitset ImpliedFeaturesEGPR = {};
+constexpr FeatureBitset ImpliedFeaturesPush2Pop2 = {};
+constexpr FeatureBitset ImpliedFeaturesPPX = {};
+constexpr FeatureBitset ImpliedFeaturesNDD = {};
+constexpr FeatureBitset ImpliedFeaturesCCMP = {};
+constexpr FeatureBitset ImpliedFeaturesCF = {};
+
 constexpr FeatureInfo FeatureInfos[X86::CPU_FEATURE_MAX] = {
 #define X86_FEATURE(ENUM, STR) {{"+" STR}, ImpliedFeatures##ENUM},
 #include "llvm/TargetParser/X86TargetParser.def"