1 diff --git a/build/moz.configure/lto-pgo.configure b/build/moz.configure/lto-pgo.configure

     2 --- a/build/moz.configure/lto-pgo.configure

     3 +++ b/build/moz.configure/lto-pgo.configure

     4 @@ -224,17 +224,20 @@ def lto(value, c_compiler, ld64_known_go

     5              #

     6              # https://github.com/llvm/llvm-project/blob/e7694f34ab6a12b8bb480cbfcb396d0a64fe965f/llvm/lib/Target/X86/X86.td#L1165-L1187

     7              if target.cpu == 'x86_64':

     8                  ldflags.append('-mllvm:-mcpu=x86-64')

     9              # We do not need special flags for arm64.  Hooray for fixed-length

    10              # instruction sets.

    11          else:

    12              num_cores = multiprocessing.cpu_count()

    13 -            cflags.append("-flto")

    14 +            if len(value) and value[0].lower() == 'full':

    15 +                cflags.append("-flto")

    16 +            else:

    17 +                cflags.append("-flto=thin")

    18              cflags.append("-flifetime-dse=1")

    19  

    20              ldflags.append("-flto=%s" % num_cores)

    21              ldflags.append("-flifetime-dse=1")

    22  

    23          # Tell LTO not to inline functions above a certain size, to mitigate

    24          # binary size growth while still getting good performance.

    25          # (For hot functions, PGO will put a multiplier on this limit.)