[MIPS] Reland Add FeatureMSA to i6400 and i6500 cores (llvm#134985) (llvm#141730)

Note: This relands llvm#134985 with a fix. Original PR resulted in test fail
for msan builds.
Fix: Initialize MipsSubtarget::ProcImpl to ProcImpl::CPU::Others


[MIPS] Reland Add FeatureMSA to i6400 and i6500 cores (llvm#134985)

- Enable 'FeatureMSA' for MIPS i6400 and i6500 cpu.
- Enable -mmsa option if mcpu is set to either i6400 or i6500
- added clang driver test to validate msa feature
- added llvm codegen test to validate msa instructions for cpu i6500 and
i6400

MIPS i6400 and i6500 cores implements and enables MSA (MIPS SIMD
ARCHITECTURE) by default.

Author: mgoudar

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

@@ -254,6 +254,12 @@ void mips::getMIPSTargetFeatures(const Driver &D, const llvm::Triple &Triple,
     D.Diag(diag::err_drv_unsupported_noabicalls_pic);
   }
 
+  if (CPUName == "i6500" || CPUName == "i6400") {
+    // MIPS cpu i6400 and i6500 support MSA (Mips SIMD Architecture)
+    // by default.
+    Features.push_back("+msa");
+  }
+
   if (!UseAbiCalls)
     Features.push_back("+noabicalls");
   else

clang/test/Driver/mips-cpus.c

@@ -0,0 +1,9 @@
+// Check target CPUs are correctly passed.
+
+// RUN: %clang --target=mips64 -### -c %s 2>&1 -mcpu=i6400 | FileCheck -check-prefix=MCPU-I6400 %s
+// MCPU-I6400: "-target-cpu" "i6400"
+// MCPU-I6400: "-target-feature" "+msa" "-target-feature" "-noabicalls"
+
+// RUN: %clang --target=mips64 -### -c %s 2>&1 -mcpu=i6500 | FileCheck -check-prefix=MCPU-I6500 %s
+// MCPU-I6500: "-target-cpu" "i6500"
+// MCPU-I6500: "-target-feature" "+msa" "-target-feature" "-noabicalls"

llvm/lib/Target/Mips/Mips.td

@@ -243,11 +243,11 @@ def ImplP5600 : SubtargetFeature<"p5600", "ProcImpl",
 // same CPU architecture.
 def ImplI6400
     : SubtargetFeature<"i6400", "ProcImpl", "MipsSubtarget::CPU::I6400",
-                       "MIPS I6400 Processor", [FeatureMips64r6]>;
+                       "MIPS I6400 Processor", [FeatureMips64r6, FeatureMSA]>;
 
 def ImplI6500
     : SubtargetFeature<"i6500", "ProcImpl", "MipsSubtarget::CPU::I6500",
-                       "MIPS I6500 Processor", [FeatureMips64r6]>;
+                       "MIPS I6500 Processor", [FeatureMips64r6, FeatureMSA]>;
 
 class Proc<string Name, list<SubtargetFeature> Features>
  : ProcessorModel<Name, MipsGenericModel, Features>;

llvm/lib/Target/Mips/MipsSubtarget.h

@@ -43,7 +43,7 @@ class MipsSubtarget : public MipsGenSubtargetInfo {
     Mips3, Mips4, Mips5, Mips64, Mips64r2, Mips64r3, Mips64r5, Mips64r6
   };
 
-  enum class CPU { P5600, I6400, I6500 };
+  enum class CPU { Others, P5600, I6400, I6500 };
 
   // Used to avoid printing dsp warnings multiple times.
   static bool DspWarningPrinted;
@@ -66,9 +66,8 @@ class MipsSubtarget : public MipsGenSubtargetInfo {
   // Mips architecture version
   MipsArchEnum MipsArchVersion;
 
-  // Processor implementation (unused but required to exist by
-  // tablegen-erated code).
-  CPU ProcImpl;
+  // Processor implementation
+  CPU ProcImpl = CPU::Others;
 
   // IsLittle - The target is Little Endian
   bool IsLittle;

llvm/test/CodeGen/Mips/msa/arithmetic.ll

@@ -1,6 +1,8 @@
 ; NOTE: Assertions have been autogenerated by utils/update_llc_test_checks.py
 ; RUN: llc -mtriple=mips -mattr=+msa,+fp64,+mips32r2 < %s | FileCheck %s --check-prefixes=ALL,MIPS
 ; RUN: llc -mtriple=mipsel -mattr=+msa,+fp64,+mips32r2 < %s | FileCheck %s --check-prefixes=ALL,MIPSEL
+; RUN: llc -mtriple=mips64 -mcpu=i6500 < %s | FileCheck %s --check-prefixes=ALL
+; RUN: llc -mtriple=mips64 -mcpu=i6400 < %s | FileCheck %s --check-prefixes=ALL
 
 define void @add_v16i8(ptr %c, ptr %a, ptr %b) nounwind {
 ; ALL-LABEL: add_v16i8: