[RISCV] Change how mtune aliases are implemented.

The previous implementation translated from names like sifive-7-series
to sifive-7-rv32 or sifive-7-rv64. This also required sifive-7-rv32
and sifive-7-rv64 to be valid CPU names. As those are not real
CPUs it doesn't make sense to accept them in -mcpu.

This patch does away with the translation and adds sifive-7-series
directly to RISCV.td. Removing sifive-7-rv32 and sifive-7-rv64.
sifive-7-series is only allowed in -mtune.

I've also added "rocket" to RISCV.td but have not removed rocket-rv32
or rocket-rv64.

To prevent -mcpu=sifive-7-series or -mcpu=rocket being used with llc,
I've added a Feature32Bit to all rv32 CPUs. And made it an error to
have an rv32 triple without Feature32Bit. sifive-7-series and rocket
do not have Feature32Bit or Feature64Bit set so the user would need
to provide -mattr=+32bit or -mattr=+64bit along with the -mcpu to
avoid the error.

SiFive no longer names their newer products with 3, 5, or 7 series.
Instead we have p200 series, x200 series, p500 series, and p600 series.
Following the previous behavior would require a sifive-p500-rv32 and
sifive-p500-rv64 in order to support -mtune=sifive-p500-series. There
is currently no p500 product, but it could start getting confusing if
there was in the future.

I'm open to hearing alternatives for how to achieve my main goal
of removing sifive-7-rv32/rv64 as a CPU name.

Reviewed By: reames

Differential Revision: https://reviews.llvm.org/D131708

clang/docs/ReleaseNotes.rst

@@ -191,6 +191,12 @@ CUDA Support in Clang
 
 - ...
 
+RISC-V Support in Clang
+-----------------------
+
+- ``sifive-7-rv32`` and ``sifive-7-rv64`` are no longer supported for `-mcpu`.
+  Use `sifive-e76`, `sifive-s76`, or `sifive-u74` instead.
+
 X86 Support in Clang
 --------------------
 

clang/lib/Driver/ToolChains/Clang.cpp

@@ -2190,10 +2190,8 @@ void Clang::AddRISCVTargetArgs(const ArgList &Args,
   SetRISCVSmallDataLimit(getToolChain(), Args, CmdArgs);
 
   if (const Arg *A = Args.getLastArg(options::OPT_mtune_EQ)) {
-    StringRef Name =
-        llvm::RISCV::resolveTuneCPUAlias(A->getValue(), Triple.isArch64Bit());
     CmdArgs.push_back("-tune-cpu");
-    CmdArgs.push_back(Name.data());
+    CmdArgs.push_back(A->getValue());
   }
 }
 

clang/test/Driver/riscv-cpus.c

@@ -7,43 +7,24 @@
 // MCPU-ROCKET64: "-nostdsysteminc" "-target-cpu" "rocket-rv64"
 // MCPU-ROCKET64: "-target-feature" "+64bit"
 
-// RUN: %clang --target=riscv32 -### -c %s 2>&1 -mcpu=sifive-7-rv32 | FileCheck -check-prefix=MCPU-SIFIVE7-32 %s
-// MCPU-SIFIVE7-32: "-nostdsysteminc" "-target-cpu" "sifive-7-rv32"
-
-// RUN: %clang --target=riscv64 -### -c %s 2>&1 -mcpu=sifive-7-rv64 | FileCheck -check-prefix=MCPU-SIFIVE7-64 %s
-// MCPU-SIFIVE7-64: "-nostdsysteminc" "-target-cpu" "sifive-7-rv64"
-// MCPU-SIFIVE7-64: "-target-feature" "+64bit"
-
 // RUN: %clang --target=riscv32 -### -c %s 2>&1 -mtune=rocket-rv32 | FileCheck -check-prefix=MTUNE-ROCKET32 %s
 // MTUNE-ROCKET32: "-tune-cpu" "rocket-rv32"
 
 // RUN: %clang --target=riscv64 -### -c %s 2>&1 -mtune=rocket-rv64 | FileCheck -check-prefix=MTUNE-ROCKET64 %s
 // MTUNE-ROCKET64: "-tune-cpu" "rocket-rv64"
 
-// RUN: %clang --target=riscv32 -### -c %s 2>&1 -mtune=sifive-7-rv32 | FileCheck -check-prefix=MTUNE-SIFIVE7-32 %s
-// MTUNE-SIFIVE7-32: "-tune-cpu" "sifive-7-rv32"
-
-// RUN: %clang --target=riscv64 -### -c %s 2>&1 -mtune=sifive-7-rv64 | FileCheck -check-prefix=MTUNE-SIFIVE7-64 %s
-// MTUNE-SIFIVE7-64: "-tune-cpu" "sifive-7-rv64"
-
 // Check mtune alias CPU has resolved to the right CPU according XLEN.
 // RUN: %clang --target=riscv32 -### -c %s 2>&1 -mtune=generic | FileCheck -check-prefix=MTUNE-GENERIC-32 %s
-// MTUNE-GENERIC-32: "-tune-cpu" "generic-rv32"
+// MTUNE-GENERIC-32: "-tune-cpu" "generic"
 
 // RUN: %clang --target=riscv64 -### -c %s 2>&1 -mtune=generic | FileCheck -check-prefix=MTUNE-GENERIC-64 %s
-// MTUNE-GENERIC-64: "-tune-cpu" "generic-rv64"
+// MTUNE-GENERIC-64: "-tune-cpu" "generic"
 
 // RUN: %clang --target=riscv32 -### -c %s 2>&1 -mtune=rocket | FileCheck -check-prefix=MTUNE-ROCKET-32 %s
-// MTUNE-ROCKET-32: "-tune-cpu" "rocket-rv32"
+// MTUNE-ROCKET-32: "-tune-cpu" "rocket"
 
 // RUN: %clang --target=riscv64 -### -c %s 2>&1 -mtune=rocket | FileCheck -check-prefix=MTUNE-ROCKET-64 %s
-// MTUNE-ROCKET-64: "-tune-cpu" "rocket-rv64"
-
-// RUN: %clang --target=riscv32 -### -c %s 2>&1 -mtune=sifive-7-series | FileCheck -check-prefix=MTUNE-SIFIVE7-SERIES-32 %s
-// MTUNE-SIFIVE7-SERIES-32: "-tune-cpu" "sifive-7-rv32"
-
-// RUN: %clang --target=riscv64 -### -c %s 2>&1 -mtune=sifive-7-series | FileCheck -check-prefix=MTUNE-SIFIVE7-SERIES-64 %s
-// MTUNE-SIFIVE7-SERIES-64: "-tune-cpu" "sifive-7-rv64"
+// MTUNE-ROCKET-64: "-tune-cpu" "rocket"
 
 // mcpu with default march
 // RUN: %clang --target=riscv64 -### -c %s 2>&1 -mcpu=sifive-e20 | FileCheck -check-prefix=MCPU-SIFIVE-E20 %s

clang/test/Misc/target-invalid-cpu-note.c

@@ -81,16 +81,16 @@
 
 // RUN: not %clang_cc1 -triple riscv32 -target-cpu not-a-cpu -fsyntax-only %s 2>&1 | FileCheck %s --check-prefix RISCV32
 // RISCV32: error: unknown target CPU 'not-a-cpu'
-// RISCV32-NEXT: note: valid target CPU values are: generic-rv32, rocket-rv32, sifive-7-rv32, sifive-e20, sifive-e21, sifive-e24, sifive-e31, sifive-e34, sifive-e76{{$}}
+// RISCV32-NEXT: note: valid target CPU values are: generic-rv32, rocket-rv32, sifive-e20, sifive-e21, sifive-e24, sifive-e31, sifive-e34, sifive-e76{{$}}
 
 // RUN: not %clang_cc1 -triple riscv64 -target-cpu not-a-cpu -fsyntax-only %s 2>&1 | FileCheck %s --check-prefix RISCV64
 // RISCV64: error: unknown target CPU 'not-a-cpu'
-// RISCV64-NEXT: note: valid target CPU values are: generic-rv64, rocket-rv64, sifive-7-rv64, sifive-s21, sifive-s51, sifive-s54, sifive-s76, sifive-u54, sifive-u74{{$}}
+// RISCV64-NEXT: note: valid target CPU values are: generic-rv64, rocket-rv64, sifive-s21, sifive-s51, sifive-s54, sifive-s76, sifive-u54, sifive-u74{{$}}
 
 // RUN: not %clang_cc1 -triple riscv32 -tune-cpu not-a-cpu -fsyntax-only %s 2>&1 | FileCheck %s --check-prefix TUNE-RISCV32
 // TUNE-RISCV32: error: unknown target CPU 'not-a-cpu'
-// TUNE-RISCV32-NEXT: note: valid target CPU values are: generic-rv32, rocket-rv32, sifive-7-rv32, sifive-e20, sifive-e21, sifive-e24, sifive-e31, sifive-e34, sifive-e76, generic, rocket, sifive-7-series{{$}}
+// TUNE-RISCV32-NEXT: note: valid target CPU values are: generic-rv32, rocket-rv32, sifive-e20, sifive-e21, sifive-e24, sifive-e31, sifive-e34, sifive-e76, generic, rocket, sifive-7-series{{$}}
 
 // RUN: not %clang_cc1 -triple riscv64 -tune-cpu not-a-cpu -fsyntax-only %s 2>&1 | FileCheck %s --check-prefix TUNE-RISCV64
 // TUNE-RISCV64: error: unknown target CPU 'not-a-cpu'
-// TUNE-RISCV64-NEXT: note: valid target CPU values are: generic-rv64, rocket-rv64, sifive-7-rv64, sifive-s21, sifive-s51, sifive-s54, sifive-s76, sifive-u54, sifive-u74, generic, rocket, sifive-7-series{{$}}
+// TUNE-RISCV64-NEXT: note: valid target CPU values are: generic-rv64, rocket-rv64, sifive-s21, sifive-s51, sifive-s54, sifive-s76, sifive-u54, sifive-u74, generic, rocket, sifive-7-series{{$}}

llvm/include/llvm/Support/RISCVTargetParser.def

@@ -1,13 +1,3 @@
-#ifndef TUNE_ALIAS
-#define TUNE_ALIAS(NAME, RV32, RV64)
-#endif
-
-TUNE_ALIAS("generic", "generic-rv32", "generic-rv64")
-TUNE_ALIAS("rocket", "rocket-rv32", "rocket-rv64")
-TUNE_ALIAS("sifive-7-series", "sifive-7-rv32", "sifive-7-rv64")
-
-#undef TUNE_ALIAS
-
 #ifndef PROC
 #define PROC(ENUM, NAME, FEATURES, DEFAULT_MARCH)
 #endif
@@ -17,8 +7,6 @@ PROC(GENERIC_RV32, {"generic-rv32"}, FK_NONE, {""})
 PROC(GENERIC_RV64, {"generic-rv64"}, FK_64BIT, {""})
 PROC(ROCKET_RV32, {"rocket-rv32"}, FK_NONE, {""})
 PROC(ROCKET_RV64, {"rocket-rv64"}, FK_64BIT, {""})
-PROC(SIFIVE_732, {"sifive-7-rv32"}, FK_NONE, {""})
-PROC(SIFIVE_764, {"sifive-7-rv64"}, FK_64BIT, {""})
 PROC(SIFIVE_E20, {"sifive-e20"}, FK_NONE, {"rv32imc"})
 PROC(SIFIVE_E21, {"sifive-e21"}, FK_NONE, {"rv32imac"})
 PROC(SIFIVE_E24, {"sifive-e24"}, FK_NONE, {"rv32imafc"})
@@ -33,3 +21,13 @@ PROC(SIFIVE_U54, {"sifive-u54"}, FK_64BIT, {"rv64gc"})
 PROC(SIFIVE_U74, {"sifive-u74"}, FK_64BIT, {"rv64gc"})
 
 #undef PROC
+
+#ifndef TUNE_PROC
+#define TUNE_PROC(ENUM, NAME)
+#endif
+
+TUNE_PROC(GENERIC, "generic")
+TUNE_PROC(ROCKET, "rocket")
+TUNE_PROC(SIFIVE_7, "sifive-7-series")
+
+#undef TUNE_PROC

llvm/include/llvm/Support/TargetParser.h

@@ -159,6 +159,7 @@ namespace RISCV {
 
 enum CPUKind : unsigned {
 #define PROC(ENUM, NAME, FEATURES, DEFAULT_MARCH) CK_##ENUM,
+#define TUNE_PROC(ENUM, NAME) CK_##ENUM,
 #include "RISCVTargetParser.def"
 };
 
@@ -176,7 +177,6 @@ StringRef getMArchFromMcpu(StringRef CPU);
 void fillValidCPUArchList(SmallVectorImpl<StringRef> &Values, bool IsRV64);
 void fillValidTuneCPUArchList(SmallVectorImpl<StringRef> &Values, bool IsRV64);
 bool getCPUFeaturesExceptStdExt(CPUKind Kind, std::vector<StringRef> &Features);
-StringRef resolveTuneCPUAlias(StringRef TuneCPU, bool IsRV64);
 
 } // namespace RISCV
 

llvm/lib/Support/TargetParser.cpp

@@ -278,6 +278,8 @@ bool checkCPUKind(CPUKind Kind, bool IsRV64) {
 bool checkTuneCPUKind(CPUKind Kind, bool IsRV64) {
   if (Kind == CK_INVALID)
     return false;
+#define TUNE_PROC(ENUM, NAME) if (Kind == CK_##ENUM) return true;
+#include "llvm/Support/RISCVTargetParser.def"
   return RISCVCPUInfo[static_cast<unsigned>(Kind)].is64Bit() == IsRV64;
 }
 
@@ -288,18 +290,10 @@ CPUKind parseCPUKind(StringRef CPU) {
       .Default(CK_INVALID);
 }
 
-StringRef resolveTuneCPUAlias(StringRef TuneCPU, bool IsRV64) {
-  return llvm::StringSwitch<StringRef>(TuneCPU)
-#define TUNE_ALIAS(NAME, RV32, RV64) .Case(NAME, IsRV64 ? StringRef(RV64) : StringRef(RV32))
-#include "llvm/Support/RISCVTargetParser.def"
-      .Default(TuneCPU);
-}
-
 CPUKind parseTuneCPUKind(StringRef TuneCPU, bool IsRV64) {
-  TuneCPU = resolveTuneCPUAlias(TuneCPU, IsRV64);
-
   return llvm::StringSwitch<CPUKind>(TuneCPU)
 #define PROC(ENUM, NAME, FEATURES, DEFAULT_MARCH) .Case(NAME, CK_##ENUM)
+#define TUNE_PROC(ENUM, NAME) .Case(NAME, CK_##ENUM)
 #include "llvm/Support/RISCVTargetParser.def"
       .Default(CK_INVALID);
 }
@@ -321,7 +315,7 @@ void fillValidTuneCPUArchList(SmallVectorImpl<StringRef> &Values, bool IsRV64) {
     if (C.Kind != CK_INVALID && IsRV64 == C.is64Bit())
       Values.emplace_back(C.Name);
   }
-#define TUNE_ALIAS(NAME, RV32, RV64) Values.emplace_back(StringRef(NAME));
+#define TUNE_PROC(ENUM, NAME) Values.emplace_back(StringRef(NAME));
 #include "llvm/Support/RISCVTargetParser.def"
 }
 

llvm/lib/Target/RISCV/MCTargetDesc/RISCVBaseInfo.cpp

@@ -97,10 +97,13 @@ namespace RISCVFeatures {
 void validate(const Triple &TT, const FeatureBitset &FeatureBits) {
   if (TT.isArch64Bit() && !FeatureBits[RISCV::Feature64Bit])
     report_fatal_error("RV64 target requires an RV64 CPU");
-  if (!TT.isArch64Bit() && FeatureBits[RISCV::Feature64Bit])
+  if (!TT.isArch64Bit() && !FeatureBits[RISCV::Feature32Bit])
     report_fatal_error("RV32 target requires an RV32 CPU");
   if (TT.isArch64Bit() && FeatureBits[RISCV::FeatureRV32E])
     report_fatal_error("RV32E can't be enabled for an RV64 target");
+  if (FeatureBits[RISCV::Feature32Bit] &&
+      FeatureBits[RISCV::Feature64Bit])
+    report_fatal_error("RV32 and RV64 can't be combined");
 }
 
 llvm::Expected<std::unique_ptr<RISCVISAInfo>>

llvm/lib/Target/RISCV/RISCV.td

@@ -447,6 +447,10 @@ def HasStdExtZicbop : Predicate<"Subtarget->hasStdExtZicbop()">,
                                 AssemblerPredicate<(all_of FeatureStdExtZicbop),
                                 "'Zicbop' (Cache-Block Prefetch Instructions)">;
 
+// Feature32Bit exists to mark CPUs that support RV32 to distinquish them from
+// tuning CPU names.
+def Feature32Bit
+    : SubtargetFeature<"32bit", "HasRV32", "true", "Implements RV32">;
 def Feature64Bit
     : SubtargetFeature<"64bit", "HasRV64", "true", "Implements RV64">;
 def IsRV64 : Predicate<"Subtarget->is64Bit()">,
@@ -527,42 +531,47 @@ include "RISCVSchedSiFive7.td"
 // RISC-V processors supported.
 //===----------------------------------------------------------------------===//
 
-def : ProcessorModel<"generic-rv32", NoSchedModel, []>;
+def : ProcessorModel<"generic-rv32", NoSchedModel, [Feature32Bit]>;
 def : ProcessorModel<"generic-rv64", NoSchedModel, [Feature64Bit]>;
 // Support generic for compatibility with other targets. The triple will be used
 // to change to the appropriate rv32/rv64 version.
 def : ProcessorModel<"generic", NoSchedModel, []>;
 
-def : ProcessorModel<"rocket-rv32", RocketModel, []>;
+def : ProcessorModel<"rocket-rv32", RocketModel, [Feature32Bit]>;
 def : ProcessorModel<"rocket-rv64", RocketModel, [Feature64Bit]>;
+def : ProcessorModel<"rocket", RocketModel, []>;
 
-def : ProcessorModel<"sifive-7-rv32", SiFive7Model, [],
-                     [TuneSiFive7]>;
-def : ProcessorModel<"sifive-7-rv64", SiFive7Model, [Feature64Bit],
+def : ProcessorModel<"sifive-7-series", SiFive7Model, [],
                      [TuneSiFive7]>;
 
-def : ProcessorModel<"sifive-e20", RocketModel, [FeatureStdExtM,
+def : ProcessorModel<"sifive-e20", RocketModel, [Feature32Bit,
+                                                 FeatureStdExtM,
                                                  FeatureStdExtC]>;
 
-def : ProcessorModel<"sifive-e21", RocketModel, [FeatureStdExtM,
+def : ProcessorModel<"sifive-e21", RocketModel, [Feature32Bit,
+                                                 FeatureStdExtM,
                                                  FeatureStdExtA,
                                                  FeatureStdExtC]>;
 
-def : ProcessorModel<"sifive-e24", RocketModel, [FeatureStdExtM,
+def : ProcessorModel<"sifive-e24", RocketModel, [Feature32Bit,
+                                                 FeatureStdExtM,
                                                  FeatureStdExtA,
                                                  FeatureStdExtF,
                                                  FeatureStdExtC]>;
 
-def : ProcessorModel<"sifive-e31", RocketModel, [FeatureStdExtM,
+def : ProcessorModel<"sifive-e31", RocketModel, [Feature32Bit,
+                                                 FeatureStdExtM,
                                                  FeatureStdExtA,
                                                  FeatureStdExtC]>;
 
-def : ProcessorModel<"sifive-e34", RocketModel, [FeatureStdExtM,
+def : ProcessorModel<"sifive-e34", RocketModel, [Feature32Bit,
+                                                 FeatureStdExtM,
                                                  FeatureStdExtA,
                                                  FeatureStdExtF,
                                                  FeatureStdExtC]>;
 
-def : ProcessorModel<"sifive-e76", SiFive7Model, [FeatureStdExtM,
+def : ProcessorModel<"sifive-e76", SiFive7Model, [Feature32Bit,
+                                                  FeatureStdExtM,
                                                   FeatureStdExtA,
                                                   FeatureStdExtF,
                                                   FeatureStdExtC],

llvm/lib/Target/RISCV/RISCVSubtarget.h

@@ -91,6 +91,7 @@ class RISCVSubtarget : public RISCVGenSubtargetInfo {
   bool HasStdExtZicboz = false;
   bool HasStdExtZicbop = false;
   bool HasStdExtZmmul = false;
+  bool HasRV32 = false;
   bool HasRV64 = false;
   bool IsRV32E = false;
   bool EnableLinkerRelax = false;

llvm/test/Transforms/LoopUnroll/RISCV/unroll.ll

@@ -1,5 +1,5 @@
 ; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
-; RUN: opt %s -S -mtriple=riscv64 -loop-unroll -mcpu=sifive-7-rv64 | FileCheck %s
+; RUN: opt %s -S -mtriple=riscv64 -loop-unroll -mcpu=sifive-s76 | FileCheck %s
 
 define dso_local void @saxpy(float %a, float* %x, float* %y) {
 ; CHECK-LABEL: @saxpy(