[PATCH][AArch64] Improve spill code - swap order in shr patterns

["Wilco Dijkstra" <wdijkstr at arm dot com>]

This is basically the same as the shl version but for the shr patterns.

Various instructions are supported as integer operations as well as SIMD on AArch64. When
register pressure is high, lra-constraints inserts spill code without taking the allocation
class into account, and basically chooses the first available pattern that matches. Since this
instruction has the SIMD version first it is usually chosen eventhough some of the operands
are eventually allocated to integer registers. The result is inefficient code not only due to
the higher latency of SIMD instructions but also due to the extra int<->FP moves. Placing the
integer variant first in the shr pattern generates far more optimal spill code.

2015-07-27  Wilco Dijkstra  <wdijkstr@arm.com>

        * gcc/config/aarch64/aarch64.md (aarch64_lshr_sisd_or_int_<mode>3):
        Place integer variant first.  (aarch64_ashr_sisd_or_int_<mode>3):
        Likewise.


---
 gcc/config/aarch64/aarch64.md | 27 ++++++++++++++-------------
 1 file changed, 14 insertions(+), 13 deletions(-)

diff --git a/gcc/config/aarch64/aarch64.md b/gcc/config/aarch64/aarch64.md
index baef56a..06256e3 100644
--- a/gcc/config/aarch64/aarch64.md
+++ b/gcc/config/aarch64/aarch64.md
@@ -3349,17 +3349,18 @@
 
 ;; Logical right shift using SISD or Integer instruction
 (define_insn "*aarch64_lshr_sisd_or_int_<mode>3"
-  [(set (match_operand:GPI 0 "register_operand" "=w,&w,r")
+  [(set (match_operand:GPI 0 "register_operand" "=r,w,&w,&w")
         (lshiftrt:GPI
-          (match_operand:GPI 1 "register_operand" "w,w,r")
-          (match_operand:QI 2 "aarch64_reg_or_shift_imm_<mode>" "Us<cmode>,w,rUs<cmode>")))]
+          (match_operand:GPI 1 "register_operand" "r,w,w,w")
+          (match_operand:QI 2 "aarch64_reg_or_shift_imm_<mode>" "rUs<cmode>,Us<cmode>,w,0")))]
   ""
   "@
+   lsr\t%<w>0, %<w>1, %<w>2
    ushr\t%<rtn>0<vas>, %<rtn>1<vas>, %2
    #
-   lsr\t%<w>0, %<w>1, %<w>2"
-  [(set_attr "simd" "yes,yes,no")
-   (set_attr "type" "neon_shift_imm<q>,neon_shift_reg<q>,shift_reg")]
+   #"
+  [(set_attr "simd" "no,yes,yes,yes")
+   (set_attr "type" "shift_reg,neon_shift_imm<q>,neon_shift_reg<q>,neon_shift_reg<q>")]
 )
 
 (define_split
@@ -3394,18 +3395,18 @@
 
 ;; Arithmetic right shift using SISD or Integer instruction
 (define_insn "*aarch64_ashr_sisd_or_int_<mode>3"
-  [(set (match_operand:GPI 0 "register_operand" "=w,&w,&w,r")
+  [(set (match_operand:GPI 0 "register_operand" "=r,w,&w,&w")
         (ashiftrt:GPI
-          (match_operand:GPI 1 "register_operand" "w,w,w,r")
-          (match_operand:QI 2 "aarch64_reg_or_shift_imm_di" "Us<cmode>,w,0,rUs<cmode>")))]
+          (match_operand:GPI 1 "register_operand" "r,w,w,w")
+          (match_operand:QI 2 "aarch64_reg_or_shift_imm_di" "rUs<cmode>,Us<cmode>,w,0")))]
   ""
   "@
+   asr\t%<w>0, %<w>1, %<w>2
    sshr\t%<rtn>0<vas>, %<rtn>1<vas>, %2
    #
-   #
-   asr\t%<w>0, %<w>1, %<w>2"
-  [(set_attr "simd" "yes,yes,yes,no")
-   (set_attr "type" "neon_shift_imm<q>,neon_shift_reg<q>,neon_shift_reg<q>,shift_reg")]
+   #"
+  [(set_attr "simd" "no,yes,yes,yes")
+   (set_attr "type" "shift_reg,neon_shift_imm<q>,neon_shift_reg<q>,neon_shift_reg<q>")]
 )
 
 (define_split
-- 
1.9.1