[clang] Mention vector in the description for -mno-implict-float.

[craig.topper]

Summary

As far as I understand, this disables all integer vectors too.

[craig.topper]

Ping

[efriedma]

LGTM

We might want per-target documentation somewhere for what counts as an "floating point or vector instruction". It's not entirely obvious whether, for example, cvtss2si (%rax), %ecx is a floating-point instruction. But I don't think we can get much more clear in a one or two line description.

clang/include/clang/Driver/Options.td

 def msoft_float : Flag<["-"], "msoft-float">, Group<m_Group>, Flags<[CC1Option]>,
   HelpText<"Use software floating point">,
   MarshallingInfoFlag<CodeGenOpts<"SoftFloat">>;
 def moutline_atomics : Flag<["-"], "moutline-atomics">, Group<f_clang_Group>, Flags<[CC1Option]>,
   HelpText<"Generate local calls to out-of-line atomic operations">;
 def mno_outline_atomics : Flag<["-"], "mno-outline-atomics">, Group<f_clang_Group>, Flags<[CC1Option]>,
   HelpText<"Don't generate local calls to out-of-line atomic operations">;
 def mno_implicit_float : Flag<["-"], "mno-implicit-float">, Group<m_Group>,
-  HelpText<"Don't generate implicit floating point instructions">;
+  HelpText<"Don't generate implicit floating point or vector instructions">;
 def mimplicit_float : Flag<["-"], "mimplicit-float">, Group<m_Group>;
 def mrecip : Flag<["-"], "mrecip">, Group<m_Group>;
 def mrecip_EQ : CommaJoined<["-"], "mrecip=">, Group<m_Group>, Flags<[CC1Option]>,
   MarshallingInfoStringVector<CodeGenOpts<"Reciprocals">>;
 def mprefer_vector_width_EQ : Joined<["-"], "mprefer-vector-width=">, Group<m_Group>, Flags<[CC1Option]>,
   HelpText<"Specifies preferred vector width for auto-vectorization. Defaults to 'none' which allows target specific decisions.">,
   MarshallingInfoString<CodeGenOpts<"PreferVectorWidth">>;
 def mstack_protector_guard_EQ : Joined<["-"], "mstack-protector-guard=">, Group<m_Group>, Flags<[CC1Option]>,

 def debug_forward_template_params : Flag<["-"], "debug-forward-template-params">,
   HelpText<"Emit complete descriptions of template parameters in forward"
            " declarations">,
   MarshallingInfoFlag<CodeGenOpts<"DebugFwdTemplateParams">>;
 def fforbid_guard_variables : Flag<["-"], "fforbid-guard-variables">,
   HelpText<"Emit an error if a C++ static local initializer would need a guard variable">,
   MarshallingInfoFlag<CodeGenOpts<"ForbidGuardVariables">>;
 def no_implicit_float : Flag<["-"], "no-implicit-float">,
-  HelpText<"Don't generate implicit floating point instructions">,
+  HelpText<"Don't generate implicit floating point or vector instructions">,
   MarshallingInfoFlag<CodeGenOpts<"NoImplicitFloat">>;
 def fdump_vtable_layouts : Flag<["-"], "fdump-vtable-layouts">,
   HelpText<"Dump the layouts of all vtables that will be emitted in a translation unit">,
   MarshallingInfoFlag<LangOpts<"DumpVTableLayouts">>;
 def fmerge_functions : Flag<["-"], "fmerge-functions">,
   HelpText<"Permit merging of identical functions when optimizing.">,
   MarshallingInfoFlag<CodeGenOpts<"MergeFunctions">>;
 def coverage_data_file : Separate<["-"], "coverage-data-file">,