[mips] Add '-mcrc', '-mno-crc' options to enable/disable CRC ASE

[vstefanovic]

Summary

'-mcrc' is shared with ARM.
'-mno-crc' is Mips-only (ARM uses '-mnocrc').

[atanasyan]

include/clang/Driver/Options.td

2215

Does it make a sense to define this option as an alias to the mnocrc and allow to use both -mno-crc and -mnocrc for ARM and MIPS?

[sdardis]

include/clang/Driver/Options.td

2215

I thought about commenting on that. The problem there is that you then permitting clang to be more lax than binutils which inhibits compatibility between the two tools.

[atanasyan]

include/clang/Driver/Options.td

2215

The problem there is that you then permitting clang to be more lax than binutils which inhibits compatibility between the two tools.

Good point. Agreed.

include/clang/Driver/Options.td

def mrestrict_it: Flag<["-"], "mrestrict-it">, Group<m_arm_Features_Group>,
   HelpText<"Disallow generation of deprecated IT blocks for ARMv8. It is on by default for ARMv8 Thumb mode.">;
 def mno_restrict_it: Flag<["-"], "mno-restrict-it">, Group<m_arm_Features_Group>,
   HelpText<"Allow generation of deprecated IT blocks for ARMv8. It is off by default for ARMv8 Thumb mode">;
 def marm : Flag<["-"], "marm">, Alias<mno_thumb>;
 def ffixed_r9 : Flag<["-"], "ffixed-r9">, Group<m_arm_Features_Group>,
   HelpText<"Reserve the r9 register (ARM only)">;
 def mno_movt : Flag<["-"], "mno-movt">, Group<m_arm_Features_Group>,
   HelpText<"Disallow use of movt/movw pairs (ARM only)">;
-def mcrc : Flag<["-"], "mcrc">, Group<m_arm_Features_Group>,
-  HelpText<"Allow use of CRC instructions (ARM only)">;
+def mcrc : Flag<["-"], "mcrc">, Group<m_Group>,
+  HelpText<"Allow use of CRC instructions (ARM/Mips only)">;
 def mnocrc : Flag<["-"], "mnocrc">, Group<m_arm_Features_Group>,
   HelpText<"Disallow use of CRC instructions (ARM only)">;
 def mno_neg_immediates: Flag<["-"], "mno-neg-immediates">, Group<m_arm_Features_Group>,
   HelpText<"Disallow converting instructions with negative immediates to their negation or inversion.">;
 
 def mgeneral_regs_only : Flag<["-"], "mgeneral-regs-only">, Group<m_aarch64_Features_Group>,
   HelpText<"Generate code which only uses the general purpose registers (AArch64 only)">;
 def mfix_cortex_a53_835769 : Flag<["-"], "mfix-cortex-a53-835769">,
def mno_embedded_data : Flag<["-"], "mno-embedded-data">,
   HelpText<"Do not place constants in the .rodata section instead of the "
            ".sdata if they meet the -G <size> threshold (MIPS)">;
 def mnan_EQ : Joined<["-"], "mnan=">, Group<m_mips_Features_Group>;
 def mabs_EQ : Joined<["-"], "mabs=">, Group<m_mips_Features_Group>;
 def mabicalls : Flag<["-"], "mabicalls">, Group<m_mips_Features_Group>,
   HelpText<"Enable SVR4-style position-independent code (Mips only)">;
 def mno_abicalls : Flag<["-"], "mno-abicalls">, Group<m_mips_Features_Group>,
   HelpText<"Disable SVR4-style position-independent code (Mips only)">;
+def mno_crc : Flag<["-"], "mno-crc">, Group<m_mips_Features_Group>,
+  HelpText<"Disallow use of CRC instructions (Mips only)">;
 def mips1 : Flag<["-"], "mips1">,
   Alias<march_EQ>, AliasArgs<["mips1"]>, Group<m_mips_Features_Group>,
   HelpText<"Equivalent to -march=mips1">, Flags<[HelpHidden]>;
 def mips2 : Flag<["-"], "mips2">,
   Alias<march_EQ>, AliasArgs<["mips2"]>, Group<m_mips_Features_Group>,
   HelpText<"Equivalent to -march=mips2">, Flags<[HelpHidden]>;
 def mips3 : Flag<["-"], "mips3">,
   Alias<march_EQ>, AliasArgs<["mips3"]>, Group<m_mips_Features_Group>,

lib/Driver/ToolChains/Arch/Mips.cpp

if (Arg *A = Args.getLastArg(options::OPT_mfp32, options::OPT_mfpxx,
     Features.push_back("+nooddspreg");
   }
 
   AddTargetFeature(Args, Features, options::OPT_mno_odd_spreg,
                    options::OPT_modd_spreg, "nooddspreg");
   AddTargetFeature(Args, Features, options::OPT_mno_madd4, options::OPT_mmadd4,
                    "nomadd4");
   AddTargetFeature(Args, Features, options::OPT_mmt, options::OPT_mno_mt, "mt");
+  AddTargetFeature(Args, Features, options::OPT_mcrc, options::OPT_mno_crc,
+                   "crc");
 
   if (Arg *A = Args.getLastArg(options::OPT_mindirect_jump_EQ)) {
     StringRef Val = StringRef(A->getValue());
     if (Val == "hazard") {
       Arg *B =
           Args.getLastArg(options::OPT_mmicromips, options::OPT_mno_micromips);
       Arg *C = Args.getLastArg(options::OPT_mips16, options::OPT_mno_mips16);
 

test/Driver/mips-features.c

 // RUN:   | FileCheck --check-prefix=NO-BRANCH-LIKELY %s
 // NO-BRANCH-LIKELY: argument unused during compilation: '-mno-branch-likely'
 
 // -mindirect-jump=hazard
 // RUN: %clang -target mips-unknown-linux-gnu -### -c %s \
 // RUN:        -mindirect-jump=hazard 2>&1 \
 // RUN:   | FileCheck --check-prefix=INDIRECT-BH %s
 // INDIRECT-BH: "-target-feature" "+use-indirect-jump-hazard"
+//
+// -mcrc
+// RUN: %clang -target mips-unknown-linux-gnu -### -c %s \
+// RUN:     -mno-crc -mcrc 2>&1 \
+// RUN:   | FileCheck --check-prefix=CHECK-CRC %s
+// CHECK-CRC: "-target-feature" "+crc"
+//
+// -mno-crc
+// RUN: %clang -target mips-unknown-linux-gnu -### -c %s \
+// RUN:     -mcrc -mno-crc 2>&1 \
+// RUN:   | FileCheck --check-prefix=CHECK-NO-CRC %s
+// CHECK-NO-CRC: "-target-feature" "-crc"