[ARM] PR target/70473: Reduce size of Cortex-A8 automaton

	PR target/70473
	* config/arm/cortex-a8-neon.md (cortex_a8_vfp_muld): Reduce
	reservation duration to 15 cycles.
	(cortex_a8_vfp_macs): Likewise.
	(cortex_a8_vfp_macd): Likewise.
	(cortex_a8_vfp_divs): Likewise.
	(cortex_a8_vfp_divd): Likewise.

From-SVN: r239772

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 9c82debc2f452ef9cab27849f4c4453073088aab..dc3cb732c88eb96ed65dda4e9c6430df5cafb302 100644 (file)
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,13 @@
+2016-08-26  Kyrylo Tkachov  <kyrylo.tkachov@arm.com>
+
+       PR target/70473
+       * config/arm/cortex-a8-neon.md (cortex_a8_vfp_muld): Reduce
+       reservation duration to 15 cycles.
+       (cortex_a8_vfp_macs): Likewise.
+       (cortex_a8_vfp_macd): Likewise.
+       (cortex_a8_vfp_divs): Likewise.
+       (cortex_a8_vfp_divd): Likewise.
+
 2016-08-26  Kyrylo Tkachov  <kyrylo.tkachov@arm.com>
 
        * config/arm/arm.c (arm_sets_movw_movt_fusible_p): New function.

diff --git a/gcc/config/arm/cortex-a8-neon.md b/gcc/config/arm/cortex-a8-neon.md
index 45f861f6c6f840bd113e468eeec5373e06058f6d..b16c29974a7278e70d64dc83b5b388aebb51718b 100644 (file)
--- a/gcc/config/arm/cortex-a8-neon.md
+++ b/gcc/config/arm/cortex-a8-neon.md
@@ -357,30 +357,34 @@
        (eq_attr "type" "fmuls"))
   "cortex_a8_vfp,cortex_a8_vfplite*11")
 
+;; Don't model a reservation for more than 15 cycles as this explodes the
+;; state space of the automaton for little gain.  It is unlikely that the
+;; scheduler will find enough instructions to hide the full latency of the
+;; instructions.
 (define_insn_reservation "cortex_a8_vfp_muld" 17
   (and (eq_attr "tune" "cortexa8")
        (eq_attr "type" "fmuld"))
-  "cortex_a8_vfp,cortex_a8_vfplite*16")
+  "cortex_a8_vfp,cortex_a8_vfplite*15")
 
 (define_insn_reservation "cortex_a8_vfp_macs" 21
   (and (eq_attr "tune" "cortexa8")
        (eq_attr "type" "fmacs,ffmas"))
-  "cortex_a8_vfp,cortex_a8_vfplite*20")
+  "cortex_a8_vfp,cortex_a8_vfplite*15")
 
 (define_insn_reservation "cortex_a8_vfp_macd" 26
   (and (eq_attr "tune" "cortexa8")
        (eq_attr "type" "fmacd,ffmad"))
-  "cortex_a8_vfp,cortex_a8_vfplite*25")
+  "cortex_a8_vfp,cortex_a8_vfplite*15")
 
 (define_insn_reservation "cortex_a8_vfp_divs" 37
   (and (eq_attr "tune" "cortexa8")
        (eq_attr "type" "fdivs, fsqrts"))
-  "cortex_a8_vfp,cortex_a8_vfplite*36")
+  "cortex_a8_vfp,cortex_a8_vfplite*15")
 
 (define_insn_reservation "cortex_a8_vfp_divd" 65
   (and (eq_attr "tune" "cortexa8")
        (eq_attr "type" "fdivd, fsqrtd"))
-  "cortex_a8_vfp,cortex_a8_vfplite*64")
+  "cortex_a8_vfp,cortex_a8_vfplite*15")
 
 ;; Comparisons can actually take 7 cycles sometimes instead of four,
 ;; but given all the other instructions lumped into type=ffarith that