Rename option `-ffavor-branchless` into `-Obranchless`

Easier to type, and consistent with `-Os` (optimize for smaller code /
optimize for fewer conditional branches).

3 files changed, 7 insertions, 7 deletions

diff --git a/backend/Selectionaux.ml b/backend/Selectionaux.ml
index de8127c6..4ca7dd21 100644
--- a/backend/Selectionaux.ml
+++ b/backend/Selectionaux.ml
@@ -80,10 +80,10 @@ let fast_cmove ty =
       assert false
 
 (* The if-conversion heuristic depend on the
-   -fif-conversion and -ffavor-branchless flags.
+   -fif-conversion and -Obranchless flags.
 
 With [-fno-if-conversion] or [-0O], if-conversion is turned off entirely.
-With [-ffavor-branchless], if-conversion is performed whenever semantically
+With [-Obranchless], if-conversion is performed whenever semantically
 correct, regardless of how much it could cost.
 Otherwise (and by default), optimization is performed when it seems beneficial.
 
@@ -106,7 +106,7 @@ instructions from the first branch.
 
 let if_conversion_heuristic cond ifso ifnot ty =
   if not !Clflags.option_fifconversion then false else
-  if !Clflags.option_ffavor_branchless then true else
+  if !Clflags.option_Obranchless then true else
   if not (fast_cmove ty) then false else
   let c1 = cost_expr ifso and c2 = cost_expr ifnot in
   c1 + c2 <= 24 && abs (c1 - c2) <= 8
diff --git a/driver/Clflags.ml b/driver/Clflags.ml
index d27871ef..2db9399f 100644
--- a/driver/Clflags.ml
+++ b/driver/Clflags.ml
@@ -28,7 +28,7 @@ let option_fconstprop = ref true
 let option_fcse = ref true
 let option_fredundancy = ref true
 let option_fifconversion = ref true
-let option_ffavor_branchless = ref false
+let option_Obranchless = ref false
 let option_falignfunctions = ref (None: int option)
 let option_falignbranchtargets = ref 0
 let option_faligncondbranchs = ref 0
diff --git a/driver/Driver.ml b/driver/Driver.ml
index 84392ef6..88be8933 100644
--- a/driver/Driver.ml
+++ b/driver/Driver.ml
@@ -187,6 +187,8 @@ Processing options:
   -O0            Do not optimize the compiled code
   -O1 -O2 -O3    Synonymous for -O
   -Os            Optimize for code size in preference to code speed
+  -Obranchless   Optimize to avoid conditional branches; try to generate
+                 branch-free instruction sequences as much as possible
   -ftailcalls    Optimize function calls in tail position [on]
   -fconst-prop   Perform global constant propagation  [on]
   -ffloat-const-prop <n>  Control constant propagation of floats
@@ -197,8 +199,6 @@ Processing options:
   -finline-functions-called-once Integrate functions only required by their
                  single caller [on]
   -fif-conversion Perform if-conversion (generation of conditional moves) [on]
-  -ffavor-branchless Favor the generation of branch-free instruction sequences,
-                     even when possibly more costly than the default   [off]
 Code generation options: (use -fno-<opt> to turn off -f<opt>)
   -ffpu          Use FP registers for some integer operations [on]
   -fsmall-data <n>  Set maximal size <n> for allocation in small data area
@@ -303,10 +303,10 @@ let cmdline_actions =
   Exact "-O", Unit (set_all optimization_options);
   _Regexp "-O[123]$", Unit (set_all optimization_options);
   Exact "-Os", Set option_Osize;
+  Exact "-Obranchless", Set option_Obranchless;
   Exact "-fsmall-data", Integer(fun n -> option_small_data := n);
   Exact "-fsmall-const", Integer(fun n -> option_small_const := n);
   Exact "-ffloat-const-prop", Integer(fun n -> option_ffloatconstprop := n); 
-  Exact "-ffavor-branchless", Set option_ffavor_branchless;
   Exact "-falign-functions", Integer(fun n -> check_align n; option_falignfunctions := Some n);
   Exact "-falign-branch-targets", Integer(fun n -> check_align n; option_falignbranchtargets := n);
   Exact "-falign-cond-branches", Integer(fun n -> check_align n; option_faligncondbranchs := n);] @