gcc/

	Backport from trunk r222805.
	2015-05-05  Matthew Wahab  <matthew.wahab@arm.com>

	* gcc/config/aarch64-protos.h (struct cpu_branch_cost): New.
        (tune_params): Add field branch_costs.
	(aarch64_branch_cost): Declare.
	* gcc/config/aarch64.c (generic_branch_cost): New.
	(generic_tunings): Set field cpu_branch_cost to generic_branch_cost.
	(cortexa53_tunings): Likewise.
	(cortexa57_tunings): Likewise.
	(thunderx_tunings): Likewise.
	(xgene1_tunings): Likewise.
	(aarch64_branch_cost): Define.
	* gcc/config/aarch64/aarch64.h (BRANCH_COST): Redefine.

Change-Id: I0173f152cf80112ef47d0ad8581b7f120c503874

3 files changed, 40 insertions, 1 deletions

diff --git a/gcc/config/aarch64/aarch64-protos.h b/gcc/config/aarch64/aarch64-protos.h
index 8676c5c9c85..232c346573f 100644
--- a/gcc/config/aarch64/aarch64-protos.h
+++ b/gcc/config/aarch64/aarch64-protos.h
@@ -162,12 +162,20 @@ struct cpu_vector_cost
   const int cond_not_taken_branch_cost;  /* Cost of not taken branch.  */
 };
 
+/* Branch costs.  */
+struct cpu_branch_cost
+{
+  const int predictable;    /* Predictable branch or optimizing for size.  */
+  const int unpredictable;  /* Unpredictable branch or optimizing for speed.  */
+};
+
 struct tune_params
 {
   const struct cpu_cost_table *const insn_extra_cost;
   const struct cpu_addrcost_table *const addr_cost;
   const struct cpu_regmove_cost *const regmove_cost;
   const struct cpu_vector_cost *const vec_costs;
+  const struct cpu_branch_cost *const branch_costs;
   const int memmov_cost;
   const int issue_rate;
   const unsigned int fuseable_ops;
@@ -182,6 +190,7 @@ struct tune_params
 HOST_WIDE_INT aarch64_initial_elimination_offset (unsigned, unsigned);
 int aarch64_get_condition_code (rtx);
 bool aarch64_bitmask_imm (HOST_WIDE_INT val, machine_mode);
+int aarch64_branch_cost (bool, bool);
 enum aarch64_symbol_type
 aarch64_classify_symbolic_expression (rtx, enum aarch64_symbol_context);
 bool aarch64_const_vec_all_same_int_p (rtx, HOST_WIDE_INT);
diff --git a/gcc/config/aarch64/aarch64.c b/gcc/config/aarch64/aarch64.c
index 256f3c8834c..5d751d06ecd 100644
--- a/gcc/config/aarch64/aarch64.c
+++ b/gcc/config/aarch64/aarch64.c
@@ -339,12 +339,20 @@ static const struct cpu_vector_cost xgene1_vector_cost =
 #define AARCH64_FUSE_ADRP_LDR	(1 << 3)
 #define AARCH64_FUSE_CMP_BRANCH	(1 << 4)
 
+/* Generic costs for branch instructions.  */
+static const struct cpu_branch_cost generic_branch_cost =
+{
+  2,  /* Predictable.  */
+  2   /* Unpredictable.  */
+};
+
 static const struct tune_params generic_tunings =
 {
   &cortexa57_extra_costs,
   &generic_addrcost_table,
   &generic_regmove_cost,
   &generic_vector_cost,
+  &generic_branch_cost,
   4, /* memmov_cost  */
   2, /* issue_rate  */
   AARCH64_FUSE_NOTHING, /* fuseable_ops  */
@@ -362,6 +370,7 @@ static const struct tune_params cortexa53_tunings =
   &generic_addrcost_table,
   &cortexa53_regmove_cost,
   &generic_vector_cost,
+  &generic_branch_cost,
   4, /* memmov_cost  */
   2, /* issue_rate  */
   (AARCH64_FUSE_MOV_MOVK | AARCH64_FUSE_ADRP_ADD
@@ -380,6 +389,7 @@ static const struct tune_params cortexa57_tunings =
   &cortexa57_addrcost_table,
   &cortexa57_regmove_cost,
   &cortexa57_vector_cost,
+  &generic_branch_cost,
   4, /* memmov_cost  */
   3, /* issue_rate  */
   (AARCH64_FUSE_MOV_MOVK | AARCH64_FUSE_ADRP_ADD
@@ -398,6 +408,7 @@ static const struct tune_params thunderx_tunings =
   &generic_addrcost_table,
   &thunderx_regmove_cost,
   &generic_vector_cost,
+  &generic_branch_cost,
   6, /* memmov_cost  */
   2, /* issue_rate  */
   AARCH64_FUSE_CMP_BRANCH, /* fuseable_ops  */
@@ -415,6 +426,7 @@ static const struct tune_params xgene1_tunings =
   &xgene1_addrcost_table,
   &xgene1_regmove_cost,
   &xgene1_vector_cost,
+  &generic_branch_cost,
   6, /* memmov_cost  */
   4, /* issue_rate  */
   AARCH64_FUSE_NOTHING, /* fuseable_ops  */
@@ -5361,6 +5373,23 @@ aarch64_address_cost (rtx x,
   return cost;
 }
 
+/* Return the cost of a branch.  If SPEED_P is true then the compiler is
+   optimizing for speed.  If PREDICTABLE_P is true then the branch is predicted
+   to be taken.  */
+
+int
+aarch64_branch_cost (bool speed_p, bool predictable_p)
+{
+  /* When optimizing for speed, use the cost of unpredictable branches.  */
+  const struct cpu_branch_cost *branch_costs =
+    aarch64_tune_params->branch_costs;
+
+  if (!speed_p || predictable_p)
+    return branch_costs->predictable;
+  else
+    return branch_costs->unpredictable;
+}
+
 /* Return true if the RTX X in mode MODE is a zero or sign extract
    usable in an ADD or SUB (extended register) instruction.  */
 static bool
diff --git a/gcc/config/aarch64/aarch64.h b/gcc/config/aarch64/aarch64.h
index 1f7187bab9b..0824f9d8f59 100644
--- a/gcc/config/aarch64/aarch64.h
+++ b/gcc/config/aarch64/aarch64.h
@@ -823,7 +823,8 @@ do {									     \
 #define TRAMPOLINE_SECTION text_section
 
 /* To start with.  */
-#define BRANCH_COST(SPEED_P, PREDICTABLE_P) 2
+#define BRANCH_COST(SPEED_P, PREDICTABLE_P) \
+  (aarch64_branch_cost (SPEED_P, PREDICTABLE_P))
 
 
 /* Assembly output.  */