[PPC64] Implement the ICBT Instruction for POWER8

[kbarton]

Summary

Add support for the ICBT instruction on POWER8.
Support for the ICBT instruction is currently present, but limited to embedded processors. This change adds a new FeatureICBT that can be used to identify whether the ICBT instruction is available on a specific processor.

[hfinkel]

LGTM.

test/CodeGen/PowerPC/ppc64-icbt-pwr7.ll

3

Please add a FIXME to this test. Crashing is not really the correct behavior here, we really should just emit nothing.

[kbarton]

Added FIXME to ppc64-icbt-pwr7.ll test case to address Hal's comments.

[wschmidt]

Looks good here as well. I'll commit on your behalf this afternoon. Thanks!

[kbarton]

Work is complete.

lib/Target/PowerPC/PPC.td

 def FeatureISEL      : SubtargetFeature<"isel","HasISEL", "true",
                                         "Enable the isel instruction">;
 def FeaturePOPCNTD   : SubtargetFeature<"popcntd","HasPOPCNTD", "true",
                                         "Enable the popcnt[dw] instructions">;
 def FeatureLDBRX     : SubtargetFeature<"ldbrx","HasLDBRX", "true",
                                         "Enable the ldbrx instruction">;
 def FeatureCMPB      : SubtargetFeature<"cmpb", "HasCMPB", "true",
                                         "Enable the cmpb instruction">;
+def FeatureICBT      : SubtargetFeature<"icbt","HasICBT", "true",
+                                        "Enable icbt instruction">;
 def FeatureBookE     : SubtargetFeature<"booke", "IsBookE", "true",
-                                        "Enable Book E instructions">;
+                                        "Enable Book E instructions",
+                                        [FeatureICBT]>;
 def FeatureMSYNC     : SubtargetFeature<"msync", "HasOnlyMSYNC", "true",
                               "Has only the msync instruction instead of sync",
                               [FeatureBookE]>;
 def FeatureE500      : SubtargetFeature<"e500", "IsE500", "true",
                                         "Enable E500/E500mc instructions">;
 def FeaturePPC4xx    : SubtargetFeature<"ppc4xx", "IsPPC4xx", "true",
                                         "Enable PPC 4xx instructions">;
 def FeaturePPC6xx    : SubtargetFeature<"ppc6xx", "IsPPC6xx", "true",

 
 //===----------------------------------------------------------------------===//
 // PowerPC processors supported.
 //
 
 def : Processor<"generic", G3Itineraries, [Directive32]>;
 def : ProcessorModel<"440", PPC440Model, [Directive440, FeatureISEL,
                                           FeatureFRES, FeatureFRSQRTE,
-                                          FeatureBookE, FeatureMSYNC,
-                                          DeprecatedMFTB]>;
+                                          FeatureICBT, FeatureBookE, 
+                                          FeatureMSYNC, DeprecatedMFTB]>;
 def : ProcessorModel<"450", PPC440Model, [Directive440, FeatureISEL,
                                           FeatureFRES, FeatureFRSQRTE,
-                                          FeatureBookE, FeatureMSYNC,
-                                          DeprecatedMFTB]>;
+                                          FeatureICBT, FeatureBookE, 
+                                          FeatureMSYNC, DeprecatedMFTB]>;
 def : Processor<"601", G3Itineraries, [Directive601]>;
 def : Processor<"602", G3Itineraries, [Directive602]>;
 def : Processor<"603", G3Itineraries, [Directive603,
                                        FeatureFRES, FeatureFRSQRTE]>;
 def : Processor<"603e", G3Itineraries, [Directive603,
                                         FeatureFRES, FeatureFRSQRTE]>;
 def : Processor<"603ev", G3Itineraries, [Directive603,
                                          FeatureFRES, FeatureFRSQRTE]>;

 def : ProcessorModel<"g5", G5Model,
                   [Directive970, FeatureAltivec,
                    FeatureMFOCRF, FeatureFSqrt, FeatureSTFIWX,
                    FeatureFRES, FeatureFRSQRTE,
                    Feature64Bit /*, Feature64BitRegs */,
                    DeprecatedMFTB, DeprecatedDST]>;
 def : ProcessorModel<"e500mc", PPCE500mcModel,
                   [DirectiveE500mc, FeatureMFOCRF,
-                   FeatureSTFIWX, FeatureBookE, FeatureISEL,
-                   DeprecatedMFTB]>;
+                   FeatureSTFIWX, FeatureICBT, FeatureBookE, 
+                   FeatureISEL, DeprecatedMFTB]>;
 def : ProcessorModel<"e5500", PPCE5500Model,
                   [DirectiveE5500, FeatureMFOCRF, Feature64Bit,
-                   FeatureSTFIWX, FeatureBookE, FeatureISEL,
-                   DeprecatedMFTB]>;
+                   FeatureSTFIWX, FeatureICBT, FeatureBookE, 
+                   FeatureISEL, DeprecatedMFTB]>;
 def : ProcessorModel<"a2", PPCA2Model,
-                  [DirectiveA2, FeatureBookE, FeatureMFOCRF,
+                  [DirectiveA2, FeatureICBT, FeatureBookE, FeatureMFOCRF,
                    FeatureFCPSGN, FeatureFSqrt, FeatureFRE, FeatureFRES,
                    FeatureFRSQRTE, FeatureFRSQRTES, FeatureRecipPrec,
                    FeatureSTFIWX, FeatureLFIWAX,
                    FeatureFPRND, FeatureFPCVT, FeatureISEL,
                    FeaturePOPCNTD, FeatureCMPB, FeatureLDBRX, Feature64Bit
                /*, Feature64BitRegs */, DeprecatedMFTB]>;
 def : ProcessorModel<"a2q", PPCA2Model,
-                  [DirectiveA2, FeatureBookE, FeatureMFOCRF,
+                  [DirectiveA2, FeatureICBT, FeatureBookE, FeatureMFOCRF,
                    FeatureFCPSGN, FeatureFSqrt, FeatureFRE, FeatureFRES,
                    FeatureFRSQRTE, FeatureFRSQRTES, FeatureRecipPrec,
                    FeatureSTFIWX, FeatureLFIWAX,
                    FeatureFPRND, FeatureFPCVT, FeatureISEL,
                    FeaturePOPCNTD, FeatureCMPB, FeatureLDBRX, Feature64Bit
                /*, Feature64BitRegs */, FeatureQPX, DeprecatedMFTB]>;
 def : ProcessorModel<"pwr3", G5Model,
                   [DirectivePwr3, FeatureAltivec,
def : ProcessorModel<"pwr7", P7Model,
                    DeprecatedMFTB, DeprecatedDST]>;
 def : ProcessorModel<"pwr8", P8Model,
                   [DirectivePwr8, FeatureAltivec, FeatureVSX, FeatureP8Vector,
                    FeatureMFOCRF, FeatureFCPSGN, FeatureFSqrt, FeatureFRE,
                    FeatureFRES, FeatureFRSQRTE, FeatureFRSQRTES,
                    FeatureRecipPrec, FeatureSTFIWX, FeatureLFIWAX,
                    FeatureFPRND, FeatureFPCVT, FeatureISEL,
                    FeaturePOPCNTD, FeatureCMPB, FeatureLDBRX,
-                   Feature64Bit /*, Feature64BitRegs */,
+                   Feature64Bit /*, Feature64BitRegs */, FeatureICBT,
                    DeprecatedMFTB, DeprecatedDST]>;
 def : Processor<"ppc", G3Itineraries, [Directive32]>;
 def : ProcessorModel<"ppc64", G5Model,
                   [Directive64, FeatureAltivec,
                    FeatureMFOCRF, FeatureFSqrt, FeatureFRES,
                    FeatureFRSQRTE, FeatureSTFIWX,
                    Feature64Bit /*, Feature64BitRegs */]>;
 def : ProcessorModel<"ppc64le", G5Model,

lib/Target/PowerPC/PPCInstrInfo.td

 def IsBookE  : Predicate<"PPCSubTarget->isBookE()">;
 def IsNotBookE  : Predicate<"!PPCSubTarget->isBookE()">;
 def HasOnlyMSYNC : Predicate<"PPCSubTarget->hasOnlyMSYNC()">;
 def HasSYNC   : Predicate<"!PPCSubTarget->hasOnlyMSYNC()">;
 def IsPPC4xx  : Predicate<"PPCSubTarget->isPPC4xx()">;
 def IsPPC6xx  : Predicate<"PPCSubTarget->isPPC6xx()">;
 def IsE500  : Predicate<"PPCSubTarget->isE500()">;
 def HasSPE  : Predicate<"PPCSubTarget->HasSPE()">;
-
+def HasICBT : Predicate<"PPCSubTarget->hasICBT()">;
 //===----------------------------------------------------------------------===//
 // PowerPC Multiclass Definitions.
 
 multiclass XForm_6r<bits<6> opcode, bits<10> xo, dag OOL, dag IOL,
                     string asmbase, string asmstr, InstrItinClass itin,
                     list<dag> pattern> {
   let BaseName = asmbase in {
     def NAME : XForm_6<opcode, xo, OOL, IOL,

 def DCBZ   : DCB_Form<1014, 0, (outs), (ins memrr:$dst), "dcbz $dst",
                       IIC_LdStDCBF, [(int_ppc_dcbz xoaddr:$dst)]>,
                       PPC970_DGroup_Single;
 def DCBZL  : DCB_Form<1014, 1, (outs), (ins memrr:$dst), "dcbzl $dst",
                       IIC_LdStDCBF, [(int_ppc_dcbzl xoaddr:$dst)]>,
                       PPC970_DGroup_Single;
 
 def ICBT  : XForm_icbt<31, 22, (outs), (ins u4imm:$CT, memrr:$src),
-                       "icbt $CT, $src", IIC_LdStLoad>, Requires<[IsBookE]>;
+                       "icbt $CT, $src", IIC_LdStLoad>, Requires<[HasICBT]>;
 
 def : Pat<(prefetch xoaddr:$dst, (i32 0), imm, (i32 1)),
           (DCBT xoaddr:$dst)>;   // data prefetch for loads
 def : Pat<(prefetch xoaddr:$dst, (i32 1), imm, (i32 1)),
           (DCBTST xoaddr:$dst)>; // data prefetch for stores
 def : Pat<(prefetch xoaddr:$dst, (i32 0), imm, (i32 0)),
-          (ICBT 0, xoaddr:$dst)>; // inst prefetch (for read)
+          (ICBT 0, xoaddr:$dst)>, Requires<[HasICBT]>; // inst prefetch (for read)
 
 // Atomic operations
 let usesCustomInserter = 1 in {
   let Defs = [CR0] in {
     def ATOMIC_LOAD_ADD_I8 : Pseudo<
       (outs gprc:$dst), (ins memrr:$ptr, gprc:$incr), "#ATOMIC_LOAD_ADD_I8",
       [(set i32:$dst, (atomic_load_add_8 xoaddr:$ptr, i32:$incr))]>;
     def ATOMIC_LOAD_SUB_I8 : Pseudo<

lib/Target/PowerPC/PPCSubtarget.h

protected:
   bool HasOnlyMSYNC;
   bool IsE500;
   bool IsPPC4xx;
   bool IsPPC6xx;
   bool DeprecatedMFTB;
   bool DeprecatedDST;
   bool HasLazyResolverStubs;
   bool IsLittleEndian;
+  bool HasICBT;
 
   enum {
     PPC_ABI_UNKNOWN,
     PPC_ABI_ELFv1,
     PPC_ABI_ELFv2
   } TargetABI;
 
   PPCFrameLowering FrameLowering;
public:
   bool hasLDBRX() const { return HasLDBRX; }
   bool isBookE() const { return IsBookE; }
   bool hasOnlyMSYNC() const { return HasOnlyMSYNC; }
   bool isPPC4xx() const { return IsPPC4xx; }
   bool isPPC6xx() const { return IsPPC6xx; }
   bool isE500() const { return IsE500; }
   bool isDeprecatedMFTB() const { return DeprecatedMFTB; }
   bool isDeprecatedDST() const { return DeprecatedDST; }
+  bool hasICBT() const { return HasICBT; }
 
   const Triple &getTargetTriple() const { return TargetTriple; }
 
   /// isDarwin - True if this is any darwin platform.
   bool isDarwin() const { return TargetTriple.isMacOSX(); }
   /// isBGQ - True if this is a BG/Q platform.
   bool isBGQ() const { return TargetTriple.getVendor() == Triple::BGQ; }
 

lib/Target/PowerPC/PPCSubtarget.cpp

void PPCSubtarget::initializeEnvironment() {
   IsBookE = false;
   HasOnlyMSYNC = false;
   IsPPC4xx = false;
   IsPPC6xx = false;
   IsE500 = false;
   DeprecatedMFTB = false;
   DeprecatedDST = false;
   HasLazyResolverStubs = false;
+  HasICBT = false;
+
 }
 
 void PPCSubtarget::initSubtargetFeatures(StringRef CPU, StringRef FS) {
   // Determine default and user specified characteristics
   std::string CPUName = CPU;
   if (CPUName.empty())
     CPUName = "generic";
 #if (defined(__APPLE__) || defined(__linux__)) && \

test/CodeGen/PowerPC/ppc64-icbt-pwr7.ll

+; Test the ICBT instruction is not emitted on POWER7
+; Based on the ppc64-prefetch.ll test
+; RUN: not llc -mtriple=powerpc64-unknown-linux-gnu -mcpu=pwr7 < %s 2>&1 | FileCheck %s
+ 
+declare void @llvm.prefetch(i8*, i32, i32, i32)
+
+define void @test(i8* %a, ...) nounwind {
+entry:
+  call void @llvm.prefetch(i8* %a, i32 0, i32 3, i32 0)
+  ret void
+
+; CHECK: Cannot select: 0x{{[0-9,a-f]+}}: ch = Prefetch 
+; CHECK: 0x{{[0-9,a-f]+}}: i32 = Constant<0> 
+; CHECK-NEXT: 0x{{[0-9,a-f]+}}: i32 = Constant<3>
+; CHECK-NEXT: 0x{{[0-9,a-f]+}}: i32 = Constant<0>
+
+}
+

test/CodeGen/PowerPC/ppc64-icbt-pwr8.ll

+; Test the ICBT instruction on POWER8
+; Copied from the ppc64-prefetch.ll test
+; RUN: llc -mtriple=powerpc64-unknown-linux-gnu -mcpu=pwr8 < %s | FileCheck %s
+
+declare void @llvm.prefetch(i8*, i32, i32, i32)
+
+define void @test(i8* %a, ...) nounwind {
+entry:
+  call void @llvm.prefetch(i8* %a, i32 0, i32 3, i32 0)
+  ret void
+
+; CHECK-LABEL: @test
+; CHECK: icbt
+}
+
+