[PATCH 1/4] df: Add -ftrack-subreg-liveness option

[Lehua Ding <lehua.ding@rivai.ai>]

Add new flag -ftrack-subreg-liveness to enable track-subreg-liveness.
This flag is enabled at -O3/fast.

gcc/ChangeLog:

	* common.opt: add -ftrack-subreg-liveness option.
	* opts.cc: auto aneble -ftrack-subreg-liveness in -O3/fast

---
 gcc/common.opt | 4 ++++
 gcc/opts.cc    | 1 +
 2 files changed, 5 insertions(+)

diff --git a/gcc/common.opt b/gcc/common.opt
index 51c4a17da83..d4592c6426a 100644
--- a/gcc/common.opt
+++ b/gcc/common.opt
@@ -2156,6 +2156,10 @@ fira-verbose=
 Common RejectNegative Joined UInteger Var(flag_ira_verbose) Init(5)
 -fira-verbose=<number>	Control IRA's level of diagnostic messages.
 
+ftrack-subreg-liveness
+Common Var(flag_track_subreg_liveness) Init(0) Optimization
+Track subreg liveness information for IRA and LRA, enabled at -O3.
+
 fivopts
 Common Var(flag_ivopts) Init(1) Optimization
 Optimize induction variables on trees.
diff --git a/gcc/opts.cc b/gcc/opts.cc
index 3333600e0ea..50c0b62c5af 100644
--- a/gcc/opts.cc
+++ b/gcc/opts.cc
@@ -689,6 +689,7 @@ static const struct default_options default_options_table[] =
     { OPT_LEVELS_3_PLUS, OPT_funswitch_loops, NULL, 1 },
     { OPT_LEVELS_3_PLUS, OPT_fvect_cost_model_, NULL, VECT_COST_MODEL_DYNAMIC },
     { OPT_LEVELS_3_PLUS, OPT_fversion_loops_for_strides, NULL, 1 },
+    { OPT_LEVELS_3_PLUS, OPT_ftrack_subreg_liveness, NULL, 1 },
 
     /* -O3 parameters.  */
     { OPT_LEVELS_3_PLUS, OPT__param_max_inline_insns_auto_, NULL, 30 },
-- 
2.36.3