Fix helptext for opt/llc after 14fc20ca6

[nemanjai]

Summary

The commit https://reviews.llvm.org/rG14fc20ca6 added some options to the X86 back end that cause the help text for opt/llc to become much harder to read. The issue is that the cl::value_desc is part of the option name and is used to compute the indentation of the description text (i.e. the maximum length option name is what everything aligns to). Since the commit puts a large number of characters into that text, everything is aligned to that width.

This patch just reformats the option so that the description is contained in the description and the list of possible values is within the angle brackets:

--x86-align-branch=<jcc, fused, jmp, call, ret, indirect> - Specify types of branches to align (plus separated list of types):
                                                            jcc      indicates conditional jumps
                                                            fused    indicates fusedconditional jumps
                                                            jmp      indicates unconditional jumps
                                                            call     indicates direct and indirect calls
                                                            ret      indicates rets
                                                            indirect indicates indirect jumps

[nemanjai]

Align the descriptions of the suboptions.

[merge_guards_bot]

Unit tests: pass. 62136 tests passed, 0 failed and 808 were skipped.

clang-tidy: pass.

clang-format: pass.

Build artifacts: diff.json, clang-tidy.txt, clang-format.patch, CMakeCache.txt, console-log.txt, test-results.xml

Pre-merge checks is in beta. Report issue. Please join beta or enable it for your project.

[merge_guards_bot]

Unit tests: pass. 62136 tests passed, 0 failed and 808 were skipped.

clang-tidy: fail. clang-tidy found 0 errors and 3 warnings. 0 of them are added as review comments below (why?).

clang-format: pass.

Build artifacts: diff.json, clang-tidy.txt, clang-format.patch, CMakeCache.txt, console-log.txt, test-results.xml

Pre-merge checks is in beta. Report issue. Please join beta or enable it for your project.

[skan]

LGTM

[annita.zhang]

Refine the wordings to make it clearer. Other than that, LGTM.

llvm/lib/Target/X86/MCTargetDesc/X86AsmBackend.cpp

90

fused conditional (add a space between)

91

indicates direct unconditional jumps

94

indicates indirect unconditional jumps

[nemanjai]

llvm/lib/Target/X86/MCTargetDesc/X86AsmBackend.cpp

90

Oops, I'll fix that. Thanks.

91

Will do.

94

Will do.

llvm/lib/Target/X86/MCTargetDesc/X86AsmBackend.cpp

cl::desc(
         "boundary's size is not 0, it should be a power of 2 and no less "
         "than 32. Branches will be aligned to prevent from being across or "
         "against the boundary of specified size. The default value 0 does not "
         "align branches."));
 
 cl::opt<X86AlignBranchKind, true, cl::parser<std::string>> X86AlignBranch(
     "x86-align-branch",
     cl::desc(
-        "Specify types of branches to align. The branches's types are "
-        "combination of jcc, fused, jmp, call, ret, indirect. jcc indicates "
-        "conditional jumps, fused indicates fused conditional jumps, jmp "
-        "indicates unconditional jumps, call indicates direct and indirect "
-        "calls, ret indicates rets, indirect indicates indirect jumps."),
-    cl::value_desc("(plus separated list of types)"),
+        "Specify types of branches to align (plus separated list of types):"
+             "\njcc      indicates conditional jumps"
+             "\nfused    indicates fused conditional jumps"
+             "\njmp      indicates direct unconditional jumps"
+             "\ncall     indicates direct and indirect calls"
+             "\nret      indicates rets"
+             "\nindirect indicates indirect unconditional jumps"),
+    cl::value_desc("jcc, fused, jmp, call, ret, indirect"),
     cl::location(X86AlignBranchKindLoc));
 
 cl::opt<bool> X86AlignBranchWithin32BBoundaries(
     "x86-branches-within-32B-boundaries", cl::init(false),
     cl::desc(
         "Align selected instructions to mitigate negative performance impact "
         "of Intel's micro code update for errata skx102.  May break "
         "assumptions about labels corresponding to particular instructions, "