[Driver] Remove dead -freroll-loops flag (#82254)

Remove the `-freroll-loops` flag, which has not had any effect since the
migration to the new pass manager. The underlying pass has been removed
entirely in #80972 due to lack of maintenance and known bugs.

Fixes #59065.

Author: nikic

clang/docs/ReleaseNotes.rst

@@ -167,6 +167,8 @@ Modified Compiler Flags
 Removed Compiler Flags
 -------------------------
 
+- The ``-freroll-loops`` flag has been removed. It had no effect since Clang 13.
+
 Attribute Changes in Clang
 --------------------------
 

clang/include/clang/Driver/Options.td

@@ -3871,10 +3871,6 @@ def funroll_loops : Flag<["-"], "funroll-loops">, Group<f_Group>,
   HelpText<"Turn on loop unroller">, Visibility<[ClangOption, CC1Option]>;
 def fno_unroll_loops : Flag<["-"], "fno-unroll-loops">, Group<f_Group>,
   HelpText<"Turn off loop unroller">, Visibility<[ClangOption, CC1Option]>;
-defm reroll_loops : BoolFOption<"reroll-loops",
-  CodeGenOpts<"RerollLoops">, DefaultFalse,
-  PosFlag<SetTrue, [], [ClangOption, CC1Option], "Turn on loop reroller">,
-  NegFlag<SetFalse>>;
 def ffinite_loops: Flag<["-"],  "ffinite-loops">, Group<f_Group>,
   HelpText<"Assume all loops are finite.">, Visibility<[ClangOption, CC1Option]>;
 def fno_finite_loops: Flag<["-"], "fno-finite-loops">, Group<f_Group>,

clang/lib/Driver/ToolChains/Clang.cpp

@@ -6660,11 +6660,6 @@ void Clang::ConstructJob(Compilation &C, const JobAction &JA,
       CmdArgs.push_back("-fwrapv");
   }
 
-  if (Arg *A = Args.getLastArg(options::OPT_freroll_loops,
-                               options::OPT_fno_reroll_loops))
-    if (A->getOption().matches(options::OPT_freroll_loops))
-      CmdArgs.push_back("-freroll-loops");
-
   Args.AddLastArg(CmdArgs, options::OPT_ffinite_loops,
                   options::OPT_fno_finite_loops);
 

clang/test/Driver/clang_f_opts.c

@@ -45,13 +45,6 @@
 // CHECK-UNROLL-LOOPS: "-funroll-loops"
 // CHECK-NO-UNROLL-LOOPS: "-fno-unroll-loops"
 
-// RUN: %clang -### -S -freroll-loops %s 2>&1 | FileCheck -check-prefix=CHECK-REROLL-LOOPS %s
-// RUN: %clang -### -S -fno-reroll-loops %s 2>&1 | FileCheck -check-prefix=CHECK-NO-REROLL-LOOPS %s
-// RUN: %clang -### -S -fno-reroll-loops -freroll-loops %s 2>&1 | FileCheck -check-prefix=CHECK-REROLL-LOOPS %s
-// RUN: %clang -### -S -freroll-loops -fno-reroll-loops %s 2>&1 | FileCheck -check-prefix=CHECK-NO-REROLL-LOOPS %s
-// CHECK-REROLL-LOOPS: "-freroll-loops"
-// CHECK-NO-REROLL-LOOPS-NOT: "-freroll-loops"
-
 // RUN: %clang -### -S -fprofile-sample-accurate %s 2>&1 | FileCheck -check-prefix=CHECK-PROFILE-SAMPLE-ACCURATE %s
 // CHECK-PROFILE-SAMPLE-ACCURATE: "-fprofile-sample-accurate"