libvpx: Pull from upstream

source/libvpx/build/make/thumb.pm

 #!/usr/bin/env perl
 ##
 ##  Copyright (c) 2013 The WebM project authors. All Rights Reserved.
 ##
 ##  Use of this source code is governed by a BSD-style license
 ##  that can be found in the LICENSE file in the root of the source
 ##  tree. An additional intellectual property rights grant can be found
 ##  in the file PATENTS.  All contributing project authors may
 ##  be found in the AUTHORS file in the root of the source tree.
 ##
@@ skipping 33 matching lines @@
     # This converts "ldrne r4, [src, -pstep, lsl #1]" into
     # "subne src, src, pstep, lsl #1", "ldrne r4, [src]",
     # "addne src, src, pstep, lsl #1". In a couple of cases where
     # this is used, it's used for two subsequent load instructions,
     # where a hand-written version of it could merge two subsequent
     # add and sub instructions.
     s/^(\s*)((ldr|str|pld)(ne)?)(\s+)(r\d+,\s*)?\[(\w+), -([^\]]+)\]/$1sub$4$5$7, $7, $8\n$1$2$5$6\[$7\]\n$1add$4$5$7, $7, $8/g;
 
     # Convert register post indexing to a separate add instruction.
     # This converts "ldrneb r9, [r0], r2" into "ldrneb r9, [r0]",
-    # "add r0, r2".
+    # "addne r0, r0, r2".
     s/^(\s*)((ldr|str)(ne)?[bhd]?)(\s+)(\w+),(\s*\w+,)?\s*\[(\w+)\],\s*(\w+)/$1$2$5$6,$7 [$8]\n$1add$4$5$8, $8, $9/g;
 
     # Convert a conditional addition to the pc register into a series of
     # instructions. This converts "addlt pc, pc, r3, lsl #2" into
     # "itttt lt", "movlt.n r12, pc", "addlt.w r12, #12",
     # "addlt.w r12, r12, r3, lsl #2", "movlt.n pc, r12".
     # This assumes that r12 is free at this point.
     s/^(\s*)addlt(\s+)pc,\s*pc,\s*(\w+),\s*lsl\s*#(\d+)/$1itttt$2lt\n$1movlt.n$2r12, pc\n$1addlt.w$2r12, #12\n$1addlt.w$2r12, r12, $3, lsl #($4-$branch_shift_offset)\n$1movlt.n$2pc, r12/g;
 
     # Convert "mov pc, lr" into "bx lr", since the former only works
     # for switching from arm to thumb (and only in armv7), but not
     # from thumb to arm.
     s/mov(\s*)pc\s*,\s*lr/bx$1lr/g;
 }
 
 1;