[PATCH][AArch64][2/2] Add rtx cost function handling of clz, clrsb, rbit

[Kyrill Tkachov]

Hi all,

Following up on patch "[1/2] Remove UNSPEC_CLS and use clrsb RTL code in its' 
place" this patch adds rtx costs handling of the CLZ, CLRSB RTL codes as well as the 
UNSPEC_RBIT unspec.

The CLZ and CLRSB cases are handled identically (they are implemented by the 
clz and cls instructions respectively).

Bootstrapped and tested on aarch64-linux.

Ok for trunk?

Thanks,
Kyrill


2014-07-22  Kyrylo Tkachov  <kyrylo.tkac...@arm.com>

        * config/aarch64/aarch64.c (aarch64_rtx_costs): Handle CLRSB, CLZ.
        (case UNSPEC): Handle UNSPEC_RBIT.

commit 8f54ebbfb9622dc53c30db11fdcd4d4602aa9d69
Author: Kyrylo Tkachov <kyrylo.tkac...@arm.com>
Date:   Tue Jul 15 15:10:19 2014 +0100

    [AArch64] RTX cost handling for clz, rbit, cls

diff --git a/gcc/config/aarch64/aarch64.c b/gcc/config/aarch64/aarch64.c
index 9f42e20..7f67b6a 100644
--- a/gcc/config/aarch64/aarch64.c
+++ b/gcc/config/aarch64/aarch64.c
@@ -5154,6 +5154,13 @@ aarch64_rtx_costs (rtx x, int code, int outer ATTRIBUTE_UNUSED,
 
       return false;
 
+    case CLRSB:
+    case CLZ:
+      if (speed)
+        *cost += extra_cost->alu.clz;
+
+      return false;
+
     case COMPARE:
       op0 = XEXP (x, 0);
       op1 = XEXP (x, 1);
@@ -5799,6 +5806,14 @@ cost_plus:
 
           return false;
         }
+
+      if (XINT (x, 1) == UNSPEC_RBIT)
+        {
+          if (speed)
+            *cost += extra_cost->alu.rev;
+
+          return false;
+        }
       break;
 
     case TRUNCATE: