Back port upstream patch r153779 for cortex-a9.

The patch gives more detailed description of cortex-A9's
pipeline. It in general improves performance on Cortex-A9.
Use -mtune=cortex-a9 to take advantage of this feature.

Change-Id: I803daa6631272a0dae3514b378b9f611b8fd2b54

2 files changed, 185 insertions, 6 deletions

diff --git a/gcc-4.4.3/README.google b/gcc-4.4.3/README.google
index 2a1437b8e..f2a16f1e8 100644
--- a/gcc-4.4.3/README.google
+++ b/gcc-4.4.3/README.google
@@ -2083,6 +2083,11 @@ gcc/tree-inline.c
   Owner: raksit
   Status: In upstream branches 4.3 and onwards.
 
+gcc/config/arm/cortex-a9.md
+  Cortex A9 machine description enhancement.
+  Owner: carrot
+  Status: back ported from upstream GCC 4.5 r153779.
+
 gcc/config/arm/arm.md
   Fix bug 3264814, which was caused by missing dependencies of a previous back
   port.
diff --git a/gcc-4.4.3/gcc/config/arm/cortex-a9.md b/gcc-4.4.3/gcc/config/arm/cortex-a9.md
index 121fd2da7..d1ad7cba7 100644
--- a/gcc-4.4.3/gcc/config/arm/cortex-a9.md
+++ b/gcc-4.4.3/gcc/config/arm/cortex-a9.md
@@ -1,6 +1,8 @@
-;; ARM Cortex-A9 VFP pipeline description
-;; Copyright (C) 2008 Free Software Foundation, Inc.
-;; Written by CodeSourcery.
+;; ARM Cortex-A9 pipeline description
+;; Copyright (C) 2008, 2009 Free Software Foundation, Inc.
+;; Originally written by CodeSourcery for VFP.
+;;
+;; Integer core pipeline description contributed by ARM Ltd.
 ;;
 ;; This file is part of GCC.
 ;;
@@ -20,9 +22,181 @@
 
 (define_automaton "cortex_a9")
 
-;; FIXME: We model a single pipeline for all instructions.
-;; Is dual-issue possible, and do we have other pipelines?
-(define_cpu_unit "cortex_a9_vfp" "cortex_a9")
+;; The Cortex-A9 integer core is modelled as a dual issue pipeline that has
+;; the following components.
+;; 1. 1 Load Store Pipeline.
+;; 2. P0 / main pipeline for data processing instructions.
+;; 3. P1 / Dual pipeline for Data processing instructions.
+;; 4. MAC pipeline for multiply as well as multiply
+;;    and accumulate instructions.
+;; 5. 1 VFP / Neon pipeline.
+;; The Load/Store and VFP/Neon pipeline are multiplexed.
+;; The P0 / main pipeline and M1 stage of the MAC pipeline are
+;;   multiplexed.
+;; The P1 / dual pipeline and M2 stage of the MAC pipeline are
+;;   multiplexed.
+;; There are only 4 register read ports and hence at any point of
+;; time we can't have issue down the E1 and the E2 ports unless
+;; of course there are bypass paths that get exercised.
+;; Both P0 and P1 have 2 stages E1 and E2.
+;; Data processing instructions issue to E1 or E2 depending on
+;; whether they have an early shift or not.
+
+
+(define_cpu_unit "cortex_a9_vfp, cortex_a9_ls" "cortex_a9")
+(define_cpu_unit "cortex_a9_p0_e1, cortex_a9_p0_e2" "cortex_a9")
+(define_cpu_unit "cortex_a9_p1_e1, cortex_a9_p1_e2" "cortex_a9")
+(define_cpu_unit "cortex_a9_p0_wb, cortex_a9_p1_wb" "cortex_a9")
+(define_cpu_unit "cortex_a9_mac_m1, cortex_a9_mac_m2" "cortex_a9")
+(define_cpu_unit "cortex_a9_branch, cortex_a9_issue_branch" "cortex_a9")
+
+(define_reservation "cortex_a9_p0_default" "cortex_a9_p0_e2, cortex_a9_p0_wb")
+(define_reservation "cortex_a9_p1_default" "cortex_a9_p1_e2, cortex_a9_p1_wb")
+(define_reservation "cortex_a9_p0_shift" "cortex_a9_p0_e1, cortex_a9_p0_default")
+(define_reservation "cortex_a9_p1_shift" "cortex_a9_p1_e1, cortex_a9_p1_default")
+
+(define_reservation "cortex_a9_multcycle1"
+  "cortex_a9_p0_e2 + cortex_a9_mac_m1 + cortex_a9_mac_m2 + \
+cortex_a9_p1_e2 + cortex_a9_p0_e1 + cortex_a9_p1_e1")
+
+(define_reservation "cortex_a9_mult16"
+  "cortex_a9_mac_m1, cortex_a9_mac_m2, cortex_a9_p0_wb")
+(define_reservation "cortex_a9_mac16"
+  "cortex_a9_multcycle1, cortex_a9_mac_m2, cortex_a9_p0_wb")
+(define_reservation "cortex_a9_mult"
+  "cortex_a9_mac_m1*2, cortex_a9_mac_m2, cortex_a9_p0_wb")
+(define_reservation "cortex_a9_mac"
+  "cortex_a9_multcycle1*2 ,cortex_a9_mac_m2, cortex_a9_p0_wb")
+
+
+;; Issue at the same time along the load store pipeline and
+;; the VFP / Neon pipeline is not possible.
+;; FIXME:: At some point we need to model the issue
+;; of the load store and the vfp being shared rather than anything else.
+
+(exclusion_set "cortex_a9_ls" "cortex_a9_vfp")
+
+
+;; Default data processing instruction without any shift
+;; The only exception to this is the mov instruction
+;; which can go down E2 without any problem.
+(define_insn_reservation "cortex_a9_dp" 2
+  (and (eq_attr "tune" "cortexa9")
+       (ior (eq_attr "type" "alu")
+	    (and (eq_attr "type" "alu_shift_reg, alu_shift")
+		 (eq_attr "insn" "mov"))))
+  "cortex_a9_p0_default|cortex_a9_p1_default")
+
+;; An instruction using the shifter will go down E1.
+(define_insn_reservation "cortex_a9_dp_shift" 3
+   (and (eq_attr "tune" "cortexa9")
+	(and (eq_attr "type" "alu_shift_reg, alu_shift")
+	     (not (eq_attr "insn" "mov"))))
+   "cortex_a9_p0_shift | cortex_a9_p1_shift")
+
+;; Loads have a latency of 4 cycles.
+;; We don't model autoincrement instructions. These
+;; instructions use the load store pipeline and 1 of
+;; the E2 units to write back the result of the increment.
+
+(define_insn_reservation "cortex_a9_load1_2" 4
+  (and (eq_attr "tune" "cortexa9")
+       (eq_attr "type" "load1, load2, load_byte"))
+  "cortex_a9_ls")
+
+;; Loads multiples and store multiples can't be issued for 2 cycles in a
+;; row. The description below assumes that addresses are 64 bit aligned.
+;; If not, there is an extra cycle latency which is not modelled.
+
+;; FIXME:: This bit might need to be reworked when we get to
+;; tuning for the VFP because strictly speaking the ldm
+;; is sent to the LSU unit as is and there is only an
+;; issue restriction between the LSU and the VFP/ Neon unit.
+
+(define_insn_reservation "cortex_a9_load3_4" 5
+  (and (eq_attr "tune" "cortexa9")
+       (eq_attr "type" "load3, load4"))
+  "cortex_a9_ls, cortex_a9_ls")
+
+(define_insn_reservation "cortex_a9_store1_2" 0
+  (and (eq_attr "tune" "cortexa9")
+       (eq_attr "type" "store1, store2"))
+  "cortex_a9_ls")
+
+;; Almost all our store multiples use an auto-increment
+;; form. Don't issue back to back load and store multiples
+;; because the load store unit will stall.
+(define_insn_reservation "cortex_a9_store3_4" 0
+  (and (eq_attr "tune" "cortexa9")
+       (eq_attr "type" "store3, store4"))
+  "cortex_a9_ls+(cortex_a9_p0_default | cortex_a9_p1_default), cortex_a9_ls")
+
+;; We get 16*16 multiply / mac results in 3 cycles.
+(define_insn_reservation "cortex_a9_mult16" 3
+  (and (eq_attr "tune" "cortexa9")
+       (eq_attr "insn" "smulxy"))
+       "cortex_a9_mult16")
+
+;; The 16*16 mac is slightly different that it
+;; reserves M1 and M2 in the same cycle.
+(define_insn_reservation "cortex_a9_mac16" 3
+  (and (eq_attr "tune" "cortexa9")
+       (eq_attr "insn" "smlaxy"))
+  "cortex_a9_mac16")
+
+
+(define_insn_reservation "cortex_a9_multiply" 4
+  (and (eq_attr "tune" "cortexa9")
+       (eq_attr "insn" "mul"))
+       "cortex_a9_mult")
+
+(define_insn_reservation "cortex_a9_mac" 4
+  (and (eq_attr "tune" "cortexa9")
+       (eq_attr "insn" "mla"))
+       "cortex_a9_mac")
+
+;; An instruction with a result in E2 can be forwarded
+;; to E2 or E1 or M1 or the load store unit in the next cycle.
+
+(define_bypass 1 "cortex_a9_dp"
+                 "cortex_a9_dp_shift, cortex_a9_multiply,
+ cortex_a9_load1_2, cortex_a9_dp, cortex_a9_store1_2,
+ cortex_a9_mult16, cortex_a9_mac16, cortex_a9_mac, cortex_a9_store3_4, cortex_a9_load3_4")
+
+(define_bypass 2 "cortex_a9_dp_shift"
+                 "cortex_a9_dp_shift, cortex_a9_multiply,
+ cortex_a9_load1_2, cortex_a9_dp, cortex_a9_store1_2,
+ cortex_a9_mult16, cortex_a9_mac16, cortex_a9_mac, cortex_a9_store3_4, cortex_a9_load3_4")
+
+;; An instruction in the load store pipeline can provide
+;; read access to a DP instruction in the P0 default pipeline
+;; before the writeback stage.
+
+(define_bypass 3 "cortex_a9_load1_2" "cortex_a9_dp, cortex_a9_load1_2,
+cortex_a9_store3_4, cortex_a9_store1_2")
+
+(define_bypass 4 "cortex_a9_load3_4" "cortex_a9_dp, cortex_a9_load1_2,
+cortex_a9_store3_4, cortex_a9_store1_2,  cortex_a9_load3_4")
+
+;; Calls and branches.
+
+;; Branch instructions
+
+(define_insn_reservation "cortex_a9_branch" 0
+  (and (eq_attr "tune" "cortexa9")
+       (eq_attr "type" "branch"))
+  "cortex_a9_branch")
+
+;; Call latencies are essentially 0 but make sure
+;; dual issue doesn't happen i.e the next instruction
+;; starts at the next cycle.
+(define_insn_reservation "cortex_a9_call"  0
+  (and (eq_attr "tune" "cortexa9")
+       (eq_attr "type" "call"))
+  "cortex_a9_issue_branch + cortex_a9_multcycle1 + cortex_a9_ls + cortex_a9_vfp")
+
+
+;; Pipelining for VFP instructions.
 
 (define_insn_reservation "cortex_a9_ffarith" 1
  (and (eq_attr "tune" "cortexa9")