diff mbox series

[ARC] Table-driven ashlsi implementation for better code/rtx_costs.

Message ID 013701da35f9$0c4cf5b0$24e6e110$@nextmovesoftware.com
State New
Headers show
Series [ARC] Table-driven ashlsi implementation for better code/rtx_costs. | expand

Commit Message

Roger Sayle Dec. 23, 2023, 11:37 p.m. UTC 
One of the cool features of the H8 backend is its use of tables to select
optimal shift implementations for different CPU variants.  This patch
borrows (plagiarizes) that idiom for SImode left shifts in the ARC backend
(for CPUs without a barrel-shifter).  This provides a convenient mechanism
for both selecting the best implementation strategy (for speed vs. size),
and providing accurate rtx_costs [without duplicating a lot of logic].
Left shift RTX costs are especially important for use in synth_mult.

An example improvement is:

int foo(int x) { return 32768*x; }

which is now generated with -O2 -mcpu=em -mswap as:

foo:    bmsk_s  r0,r0,16
        swap    r0,r0
        j_s.d   [blink]
        ror     r0,r0

where previously the ARC backend would generate a loop:

foo:    mov     lp_count,15
        lp      2f
        add     r0,r0,r0
        nop
2:      # end single insn loop
        j_s     [blink]


Tested with a cross-compiler to arc-linux hosted on x86_64,
with no new (compile-only) regressions from make -k check.
Ok for mainline if this passes Claudiu's and/or Jeff's testing?
[Thanks again to Jeff for finding the typo in my last ARC patch]

2023-12-23  Roger Sayle  <roger@nextmovesoftware.com>

gcc/ChangeLog
        * config/arc/arc.cc (arc_shift_alg): New enumerated type for
        left shift implementation strategies.
        (arc_shift_info): Type for each entry of the shift strategy table.
        (arc_shift_context_idx): Return a integer value for each code
        generation context, used as an index
        (arc_ashl_alg): Table indexed by context and shifted bit count.
        (arc_split_ashl): Use the arc_ashl_alg table to select SImode
        left shift implementation.
        (arc_rtx_costs) <case ASHIFT>: Use the arc_ashl_alg table to
        provide accurate costs, when optimizing for speed or size.


Thanks in advance,
Roger
--

Comments

Jeff Law Dec. 28, 2023, 4:10 p.m. UTC | #1 
On 12/23/23 16:37, Roger Sayle wrote:
> 
> One of the cool features of the H8 backend is its use of tables to select
> optimal shift implementations for different CPU variants.  This patch
> borrows (plagiarizes) that idiom for SImode left shifts in the ARC backend
> (for CPUs without a barrel-shifter).  This provides a convenient mechanism
> for both selecting the best implementation strategy (for speed vs. size),
> and providing accurate rtx_costs [without duplicating a lot of logic].
> Left shift RTX costs are especially important for use in synth_mult.
> 
> An example improvement is:
> 
> int foo(int x) { return 32768*x; }
> 
> which is now generated with -O2 -mcpu=em -mswap as:
> 
> foo:    bmsk_s  r0,r0,16
>          swap    r0,r0
>          j_s.d   [blink]
>          ror     r0,r0
> 
> where previously the ARC backend would generate a loop:
> 
> foo:    mov     lp_count,15
>          lp      2f
>          add     r0,r0,r0
>          nop
> 2:      # end single insn loop
>          j_s     [blink]
> 
> 
> Tested with a cross-compiler to arc-linux hosted on x86_64,
> with no new (compile-only) regressions from make -k check.
> Ok for mainline if this passes Claudiu's and/or Jeff's testing?
> [Thanks again to Jeff for finding the typo in my last ARC patch]
So just an FYI.  There's no upstream gdbsim for the arc, so my tester 
just uses a dummy simulator which says everything passes.

So I could include your patch to test that the compiler doesn't ICE, 
produces results that will assemble/link, but it won't test the 
correctness of the resulting code.

Jeff
Claudiu Zissulescu Jan. 9, 2024, 8:41 a.m. UTC | #2 
HI Roger,

It looks good. 

Thank you for your contribution,
Claudiu

-----Original Message-----
From: Roger Sayle <roger@nextmovesoftware.com> 
Sent: Sunday, December 24, 2023 1:38 AM
To: gcc-patches@gcc.gnu.org
Cc: 'Claudiu Zissulescu' <claziss@gmail.com>; 'Jeff Law' <jeffreyalaw@gmail.com>
Subject: [ARC PATCH] Table-driven ashlsi implementation for better code/rtx_costs.


One of the cool features of the H8 backend is its use of tables to select optimal shift implementations for different CPU variants.  This patch borrows (plagiarizes) that idiom for SImode left shifts in the ARC backend (for CPUs without a barrel-shifter).  This provides a convenient mechanism for both selecting the best implementation strategy (for speed vs. size), and providing accurate rtx_costs [without duplicating a lot of logic].
Left shift RTX costs are especially important for use in synth_mult.

An example improvement is:

int foo(int x) { return 32768*x; }

which is now generated with -O2 -mcpu=em -mswap as:

foo:    bmsk_s  r0,r0,16
        swap    r0,r0
        j_s.d   [blink]
        ror     r0,r0

where previously the ARC backend would generate a loop:

foo:    mov     lp_count,15
        lp      2f
        add     r0,r0,r0
        nop
2:      # end single insn loop
        j_s     [blink]


Tested with a cross-compiler to arc-linux hosted on x86_64, with no new (compile-only) regressions from make -k check.
Ok for mainline if this passes Claudiu's and/or Jeff's testing?
[Thanks again to Jeff for finding the typo in my last ARC patch]

2023-12-23  Roger Sayle  <roger@nextmovesoftware.com>

gcc/ChangeLog
        * config/arc/arc.cc (arc_shift_alg): New enumerated type for
        left shift implementation strategies.
        (arc_shift_info): Type for each entry of the shift strategy table.
        (arc_shift_context_idx): Return a integer value for each code
        generation context, used as an index
        (arc_ashl_alg): Table indexed by context and shifted bit count.
        (arc_split_ashl): Use the arc_ashl_alg table to select SImode
        left shift implementation.
        (arc_rtx_costs) <case ASHIFT>: Use the arc_ashl_alg table to
        provide accurate costs, when optimizing for speed or size.


Thanks in advance,
Roger
--
diff mbox series

Patch

diff --git a/gcc/config/arc/arc.cc b/gcc/config/arc/arc.cc
index 3f4eb5a5736..925bffaa7d6 100644
--- a/gcc/config/arc/arc.cc
+++ b/gcc/config/arc/arc.cc
@@ -4222,6 +4222,253 @@  output_shift_loop (enum rtx_code code, rtx *operands)
   return "";
 }
 
+/* See below where shifts are handled for explanation of this enum.  */
+enum arc_shift_alg
+{
+  SHIFT_MOVE,		/* Register-to-register move.  */
+  SHIFT_LOOP,		/* Zero-overhead loop implementation.  */
+  SHIFT_INLINE,		/* Mmultiple LSHIFTs and LSHIFT-PLUSs.  */ 
+  SHIFT_AND_ROT,        /* Bitwise AND, then ROTATERTs.  */
+  SHIFT_SWAP,		/* SWAP then multiple LSHIFTs/LSHIFT-PLUSs.  */
+  SHIFT_AND_SWAP_ROT	/* Bitwise AND, then SWAP, then ROTATERTs.  */
+};
+
+struct arc_shift_info {
+  enum arc_shift_alg alg;
+  unsigned int cost;
+};
+
+/* Return shift algorithm context, an index into the following tables.
+ * 0 for -Os (optimize for size)	3 for -O2 (optimized for speed)
+ * 1 for -Os -mswap TARGET_V2		4 for -O2 -mswap TARGET_V2
+ * 2 for -Os -mswap !TARGET_V2		5 for -O2 -mswap !TARGET_V2  */
+static unsigned int
+arc_shift_context_idx ()
+{
+  if (optimize_function_for_size_p (cfun))
+    {
+      if (!TARGET_SWAP)
+	return 0;
+      if (TARGET_V2)
+	return 1;
+      return 2;
+    }
+  else
+    {
+      if (!TARGET_SWAP)
+	return 3;
+      if (TARGET_V2)
+	return 4;
+      return 5;
+    }
+}
+
+static const arc_shift_info arc_ashl_alg[6][32] = {
+  {  /* 0: -Os.  */
+    { SHIFT_MOVE,         COSTS_N_INSNS (1) },  /*  0 */
+    { SHIFT_INLINE,       COSTS_N_INSNS (1) },  /*  1 */
+    { SHIFT_INLINE,       COSTS_N_INSNS (2) },  /*  2 */
+    { SHIFT_INLINE,       COSTS_N_INSNS (2) },  /*  3 */
+    { SHIFT_INLINE,       COSTS_N_INSNS (3) },  /*  4 */
+    { SHIFT_INLINE,       COSTS_N_INSNS (3) },  /*  5 */
+    { SHIFT_INLINE,       COSTS_N_INSNS (3) },  /*  6 */
+    { SHIFT_INLINE,       COSTS_N_INSNS (4) },  /*  7 */
+    { SHIFT_INLINE,       COSTS_N_INSNS (4) },  /*  8 */
+    { SHIFT_INLINE,       COSTS_N_INSNS (4) },  /*  9 */
+    { SHIFT_LOOP,         COSTS_N_INSNS (4) },  /* 10 */
+    { SHIFT_LOOP,         COSTS_N_INSNS (4) },  /* 11 */
+    { SHIFT_LOOP,         COSTS_N_INSNS (4) },  /* 12 */
+    { SHIFT_LOOP,         COSTS_N_INSNS (4) },  /* 13 */
+    { SHIFT_LOOP,         COSTS_N_INSNS (4) },  /* 14 */
+    { SHIFT_LOOP,         COSTS_N_INSNS (4) },  /* 15 */
+    { SHIFT_LOOP,         COSTS_N_INSNS (4) },  /* 16 */
+    { SHIFT_LOOP,         COSTS_N_INSNS (4) },  /* 17 */
+    { SHIFT_LOOP,         COSTS_N_INSNS (4) },  /* 18 */
+    { SHIFT_LOOP,         COSTS_N_INSNS (4) },  /* 19 */
+    { SHIFT_LOOP,         COSTS_N_INSNS (4) },  /* 20 */
+    { SHIFT_LOOP,         COSTS_N_INSNS (4) },  /* 21 */
+    { SHIFT_LOOP,         COSTS_N_INSNS (4) },  /* 22 */
+    { SHIFT_LOOP,         COSTS_N_INSNS (4) },  /* 23 */
+    { SHIFT_LOOP,         COSTS_N_INSNS (4) },  /* 24 */
+    { SHIFT_LOOP,         COSTS_N_INSNS (4) },  /* 25 */
+    { SHIFT_LOOP,         COSTS_N_INSNS (4) },  /* 26 */
+    { SHIFT_LOOP,         COSTS_N_INSNS (4) },  /* 27 */
+    { SHIFT_LOOP,         COSTS_N_INSNS (4) },  /* 28 */
+    { SHIFT_AND_ROT,      COSTS_N_INSNS (4) },  /* 29 */
+    { SHIFT_AND_ROT,      COSTS_N_INSNS (3) },  /* 30 */
+    { SHIFT_AND_ROT,      COSTS_N_INSNS (2) }   /* 31 */
+  },
+  {  /* 1: -Os -mswap TARGET_V2.  */
+    { SHIFT_MOVE,         COSTS_N_INSNS (1) },  /*  0 */
+    { SHIFT_INLINE,       COSTS_N_INSNS (1) },  /*  1 */
+    { SHIFT_INLINE,       COSTS_N_INSNS (2) },  /*  2 */
+    { SHIFT_INLINE,       COSTS_N_INSNS (2) },  /*  3 */
+    { SHIFT_INLINE,       COSTS_N_INSNS (3) },  /*  4 */
+    { SHIFT_INLINE,       COSTS_N_INSNS (3) },  /*  5 */
+    { SHIFT_INLINE,       COSTS_N_INSNS (3) },  /*  6 */
+    { SHIFT_INLINE,       COSTS_N_INSNS (4) },  /*  7 */
+    { SHIFT_INLINE,       COSTS_N_INSNS (4) },  /*  8 */
+    { SHIFT_INLINE,       COSTS_N_INSNS (4) },  /*  9 */
+    { SHIFT_LOOP,         COSTS_N_INSNS (4) },  /* 10 */
+    { SHIFT_LOOP,         COSTS_N_INSNS (4) },  /* 11 */
+    { SHIFT_LOOP,         COSTS_N_INSNS (4) },  /* 12 */
+    { SHIFT_LOOP,         COSTS_N_INSNS (4) },  /* 13 */
+    { SHIFT_AND_SWAP_ROT, COSTS_N_INSNS (4) },  /* 14 */
+    { SHIFT_AND_SWAP_ROT, COSTS_N_INSNS (3) },  /* 15 */
+    { SHIFT_SWAP,         COSTS_N_INSNS (1) },  /* 16 */
+    { SHIFT_SWAP,         COSTS_N_INSNS (2) },  /* 17 */
+    { SHIFT_SWAP,         COSTS_N_INSNS (3) },  /* 18 */
+    { SHIFT_SWAP,         COSTS_N_INSNS (3) },  /* 19 */
+    { SHIFT_SWAP,         COSTS_N_INSNS (4) },  /* 20 */
+    { SHIFT_SWAP,         COSTS_N_INSNS (4) },  /* 21 */
+    { SHIFT_SWAP,         COSTS_N_INSNS (4) },  /* 22 */
+    { SHIFT_LOOP,         COSTS_N_INSNS (4) },  /* 23 */
+    { SHIFT_LOOP,         COSTS_N_INSNS (4) },  /* 24 */
+    { SHIFT_LOOP,         COSTS_N_INSNS (4) },  /* 25 */
+    { SHIFT_LOOP,         COSTS_N_INSNS (4) },  /* 26 */
+    { SHIFT_LOOP,         COSTS_N_INSNS (4) },  /* 27 */
+    { SHIFT_LOOP,         COSTS_N_INSNS (4) },  /* 28 */
+    { SHIFT_AND_ROT,      COSTS_N_INSNS (4) },  /* 29 */
+    { SHIFT_AND_ROT,      COSTS_N_INSNS (3) },  /* 30 */
+    { SHIFT_AND_ROT,      COSTS_N_INSNS (2) }   /* 31 */
+  },
+  {  /* 2: -Os -mswap !TARGET_V2.  */
+    { SHIFT_MOVE,         COSTS_N_INSNS (1) },  /*  0 */
+    { SHIFT_INLINE,       COSTS_N_INSNS (1) },  /*  1 */
+    { SHIFT_INLINE,       COSTS_N_INSNS (2) },  /*  2 */
+    { SHIFT_INLINE,       COSTS_N_INSNS (2) },  /*  3 */
+    { SHIFT_INLINE,       COSTS_N_INSNS (3) },  /*  4 */
+    { SHIFT_INLINE,       COSTS_N_INSNS (3) },  /*  5 */
+    { SHIFT_INLINE,       COSTS_N_INSNS (3) },  /*  6 */
+    { SHIFT_INLINE,       COSTS_N_INSNS (4) },  /*  7 */
+    { SHIFT_INLINE,       COSTS_N_INSNS (4) },  /*  8 */
+    { SHIFT_INLINE,       COSTS_N_INSNS (4) },  /*  9 */
+    { SHIFT_LOOP,         COSTS_N_INSNS (4) },  /* 10 */
+    { SHIFT_LOOP,         COSTS_N_INSNS (4) },  /* 11 */
+    { SHIFT_LOOP,         COSTS_N_INSNS (4) },  /* 12 */
+    { SHIFT_LOOP,         COSTS_N_INSNS (4) },  /* 13 */
+    { SHIFT_AND_SWAP_ROT, COSTS_N_INSNS (4) },  /* 14 */
+    { SHIFT_AND_SWAP_ROT, COSTS_N_INSNS (3) },  /* 15 */
+    { SHIFT_SWAP,         COSTS_N_INSNS (2) },  /* 16 */
+    { SHIFT_SWAP,         COSTS_N_INSNS (3) },  /* 17 */
+    { SHIFT_SWAP,         COSTS_N_INSNS (4) },  /* 18 */
+    { SHIFT_SWAP,         COSTS_N_INSNS (4) },  /* 19 */
+    { SHIFT_LOOP,         COSTS_N_INSNS (4) },  /* 20 */
+    { SHIFT_LOOP,         COSTS_N_INSNS (4) },  /* 21 */
+    { SHIFT_LOOP,         COSTS_N_INSNS (4) },  /* 22 */
+    { SHIFT_LOOP,         COSTS_N_INSNS (4) },  /* 23 */
+    { SHIFT_LOOP,         COSTS_N_INSNS (4) },  /* 24 */
+    { SHIFT_LOOP,         COSTS_N_INSNS (4) },  /* 25 */
+    { SHIFT_LOOP,         COSTS_N_INSNS (4) },  /* 26 */
+    { SHIFT_LOOP,         COSTS_N_INSNS (4) },  /* 27 */
+    { SHIFT_LOOP,         COSTS_N_INSNS (4) },  /* 28 */
+    { SHIFT_AND_ROT,      COSTS_N_INSNS (4) },  /* 29 */
+    { SHIFT_AND_ROT,      COSTS_N_INSNS (3) },  /* 30 */
+    { SHIFT_AND_ROT,      COSTS_N_INSNS (2) }   /* 31 */
+  },
+  {  /* 3: -O2.  */
+    { SHIFT_MOVE,         COSTS_N_INSNS (1) },  /*  0 */
+    { SHIFT_INLINE,       COSTS_N_INSNS (1) },  /*  1 */
+    { SHIFT_INLINE,       COSTS_N_INSNS (2) },  /*  2 */
+    { SHIFT_INLINE,       COSTS_N_INSNS (2) },  /*  3 */
+    { SHIFT_INLINE,       COSTS_N_INSNS (3) },  /*  4 */
+    { SHIFT_INLINE,       COSTS_N_INSNS (3) },  /*  5 */
+    { SHIFT_INLINE,       COSTS_N_INSNS (3) },  /*  6 */
+    { SHIFT_INLINE,       COSTS_N_INSNS (4) },  /*  7 */
+    { SHIFT_INLINE,       COSTS_N_INSNS (4) },  /*  8 */
+    { SHIFT_INLINE,       COSTS_N_INSNS (4) },  /*  9 */
+    { SHIFT_INLINE,       COSTS_N_INSNS (5) },  /* 10 */
+    { SHIFT_INLINE,       COSTS_N_INSNS (5) },  /* 11 */
+    { SHIFT_INLINE,       COSTS_N_INSNS (5) },  /* 12 */
+    { SHIFT_INLINE,       COSTS_N_INSNS (6) },  /* 13 */
+    { SHIFT_INLINE,       COSTS_N_INSNS (6) },  /* 14 */
+    { SHIFT_INLINE,       COSTS_N_INSNS (6) },  /* 15 */
+    { SHIFT_INLINE,       COSTS_N_INSNS (7) },  /* 16 */
+    { SHIFT_INLINE,       COSTS_N_INSNS (7) },  /* 17 */
+    { SHIFT_INLINE,       COSTS_N_INSNS (7) },  /* 18 */
+    { SHIFT_INLINE,       COSTS_N_INSNS (8) },  /* 19 */
+    { SHIFT_INLINE,       COSTS_N_INSNS (8) },  /* 20 */
+    { SHIFT_INLINE,       COSTS_N_INSNS (8) },  /* 21 */
+    { SHIFT_INLINE,       COSTS_N_INSNS (9) },  /* 22 */
+    { SHIFT_INLINE,       COSTS_N_INSNS (9) },  /* 23 */
+    { SHIFT_AND_ROT,      COSTS_N_INSNS (9) },  /* 24 */
+    { SHIFT_AND_ROT,      COSTS_N_INSNS (8) },  /* 25 */
+    { SHIFT_AND_ROT,      COSTS_N_INSNS (7) },  /* 26 */
+    { SHIFT_AND_ROT,      COSTS_N_INSNS (6) },  /* 27 */
+    { SHIFT_AND_ROT,      COSTS_N_INSNS (5) },  /* 28 */
+    { SHIFT_AND_ROT,      COSTS_N_INSNS (4) },  /* 29 */
+    { SHIFT_AND_ROT,      COSTS_N_INSNS (3) },  /* 30 */
+    { SHIFT_AND_ROT,      COSTS_N_INSNS (2) }   /* 31 */
+  },
+  {  /* 4: -O2 -mswap TARGET_V2.  */
+    { SHIFT_MOVE,         COSTS_N_INSNS (1) },  /*  0 */
+    { SHIFT_INLINE,       COSTS_N_INSNS (1) },  /*  1 */
+    { SHIFT_INLINE,       COSTS_N_INSNS (2) },  /*  2 */
+    { SHIFT_INLINE,       COSTS_N_INSNS (2) },  /*  3 */
+    { SHIFT_INLINE,       COSTS_N_INSNS (3) },  /*  4 */
+    { SHIFT_INLINE,       COSTS_N_INSNS (3) },  /*  5 */
+    { SHIFT_INLINE,       COSTS_N_INSNS (3) },  /*  6 */
+    { SHIFT_INLINE,       COSTS_N_INSNS (4) },  /*  7 */
+    { SHIFT_INLINE,       COSTS_N_INSNS (4) },  /*  8 */
+    { SHIFT_INLINE,       COSTS_N_INSNS (4) },  /*  9 */
+    { SHIFT_INLINE,       COSTS_N_INSNS (5) },  /* 10 */
+    { SHIFT_INLINE,       COSTS_N_INSNS (5) },  /* 11 */
+    { SHIFT_INLINE,       COSTS_N_INSNS (5) },  /* 12 */
+    { SHIFT_AND_SWAP_ROT, COSTS_N_INSNS (5) },  /* 13 */
+    { SHIFT_AND_SWAP_ROT, COSTS_N_INSNS (4) },  /* 14 */
+    { SHIFT_AND_SWAP_ROT, COSTS_N_INSNS (3) },  /* 15 */
+    { SHIFT_SWAP,         COSTS_N_INSNS (1) },  /* 16 */
+    { SHIFT_SWAP,         COSTS_N_INSNS (2) },  /* 17 */
+    { SHIFT_SWAP,         COSTS_N_INSNS (3) },  /* 18 */
+    { SHIFT_SWAP,         COSTS_N_INSNS (3) },  /* 19 */
+    { SHIFT_SWAP,         COSTS_N_INSNS (4) },  /* 20 */
+    { SHIFT_SWAP,         COSTS_N_INSNS (4) },  /* 21 */
+    { SHIFT_SWAP,         COSTS_N_INSNS (4) },  /* 22 */
+    { SHIFT_SWAP,         COSTS_N_INSNS (5) },  /* 23 */
+    { SHIFT_SWAP,         COSTS_N_INSNS (5) },  /* 24 */
+    { SHIFT_SWAP,         COSTS_N_INSNS (5) },  /* 25 */
+    { SHIFT_SWAP,         COSTS_N_INSNS (6) },  /* 26 */
+    { SHIFT_AND_ROT,      COSTS_N_INSNS (6) },  /* 27 */
+    { SHIFT_AND_ROT,      COSTS_N_INSNS (5) },  /* 28 */
+    { SHIFT_AND_ROT,      COSTS_N_INSNS (4) },  /* 29 */
+    { SHIFT_AND_ROT,      COSTS_N_INSNS (3) },  /* 30 */
+    { SHIFT_AND_ROT,      COSTS_N_INSNS (2) }   /* 31 */
+  },
+  {  /* 5: -O2 -mswap !TARGET_V2.  */
+    { SHIFT_MOVE,         COSTS_N_INSNS (1) },  /*  0 */
+    { SHIFT_INLINE,       COSTS_N_INSNS (1) },  /*  1 */
+    { SHIFT_INLINE,       COSTS_N_INSNS (2) },  /*  2 */
+    { SHIFT_INLINE,       COSTS_N_INSNS (2) },  /*  3 */
+    { SHIFT_INLINE,       COSTS_N_INSNS (3) },  /*  4 */
+    { SHIFT_INLINE,       COSTS_N_INSNS (3) },  /*  5 */
+    { SHIFT_INLINE,       COSTS_N_INSNS (3) },  /*  6 */
+    { SHIFT_INLINE,       COSTS_N_INSNS (4) },  /*  7 */
+    { SHIFT_INLINE,       COSTS_N_INSNS (4) },  /*  8 */
+    { SHIFT_INLINE,       COSTS_N_INSNS (4) },  /*  9 */
+    { SHIFT_INLINE,       COSTS_N_INSNS (5) },  /* 10 */
+    { SHIFT_INLINE,       COSTS_N_INSNS (5) },  /* 11 */
+    { SHIFT_INLINE,       COSTS_N_INSNS (5) },  /* 12 */
+    { SHIFT_AND_SWAP_ROT, COSTS_N_INSNS (5) },  /* 13 */
+    { SHIFT_AND_SWAP_ROT, COSTS_N_INSNS (4) },  /* 14 */
+    { SHIFT_AND_SWAP_ROT, COSTS_N_INSNS (3) },  /* 15 */
+    { SHIFT_SWAP,         COSTS_N_INSNS (2) },  /* 16 */
+    { SHIFT_SWAP,         COSTS_N_INSNS (3) },  /* 17 */
+    { SHIFT_SWAP,         COSTS_N_INSNS (4) },  /* 18 */
+    { SHIFT_SWAP,         COSTS_N_INSNS (4) },  /* 19 */
+    { SHIFT_SWAP,         COSTS_N_INSNS (5) },  /* 20 */
+    { SHIFT_SWAP,         COSTS_N_INSNS (5) },  /* 21 */
+    { SHIFT_SWAP,         COSTS_N_INSNS (5) },  /* 22 */
+    { SHIFT_SWAP,         COSTS_N_INSNS (6) },  /* 23 */
+    { SHIFT_SWAP,         COSTS_N_INSNS (6) },  /* 24 */
+    { SHIFT_SWAP,         COSTS_N_INSNS (6) },  /* 25 */
+    { SHIFT_AND_ROT,      COSTS_N_INSNS (7) },  /* 26 */
+    { SHIFT_AND_ROT,      COSTS_N_INSNS (6) },  /* 27 */
+    { SHIFT_AND_ROT,      COSTS_N_INSNS (5) },  /* 28 */
+    { SHIFT_AND_ROT,      COSTS_N_INSNS (4) },  /* 29 */
+    { SHIFT_AND_ROT,      COSTS_N_INSNS (3) },  /* 30 */
+    { SHIFT_AND_ROT,      COSTS_N_INSNS (2) }   /* 31 */
+  }
+};
 
 /* Split SImode left shift instruction.  */
 void
@@ -4230,11 +4477,29 @@  arc_split_ashl (rtx *operands)
   if (CONST_INT_P (operands[2]))
     {
       int n = INTVAL (operands[2]) & 0x1f;
-      if (n <= 9)
+      switch (arc_ashl_alg [arc_shift_context_idx ()][n].alg)
 	{
+	case SHIFT_MOVE:
+	  emit_move_insn (operands[0], operands[1]);
+	  return;
+
+	case SHIFT_SWAP:
+	  if (!TARGET_V2)
+	    {
+	      emit_insn (gen_andsi3_i (operands[0], operands[1],
+				       GEN_INT (0xffff)));
+	      emit_insn (gen_rotrsi2_cnt16 (operands[0], operands[0]));
+	    }
+	  else
+	    emit_insn (gen_ashlsi2_cnt16 (operands[0], operands[1]));
+	  n -= 16;
 	  if (n == 0)
-	    emit_move_insn (operands[0], operands[1]);
-	  else if (n <= 2)
+	    return;
+	  operands[1] = operands[0];
+	  /* FALL THRU */
+
+	case SHIFT_INLINE:
+	  if (n <= 2)
 	    {
 	      emit_insn (gen_ashlsi3_cnt1 (operands[0], operands[1]));
 	      if (n == 2)
@@ -4256,37 +4521,27 @@  arc_split_ashl (rtx *operands)
 		emit_insn (gen_ashlsi3_cnt1 (operands[0], operands[0]));
 	    }
 	  return;
-	}
-      else if (n >= 16 && n <= 22 && TARGET_SWAP && TARGET_V2)
-	{
-	  emit_insn (gen_ashlsi2_cnt16 (operands[0], operands[1]));
-	  if (n > 16)
-	    {
-	      operands[1] = operands[0];
-	      operands[2] = GEN_INT (n - 16);
-	      arc_split_ashl (operands);
-	    }
+
+	case SHIFT_AND_ROT:
+	  emit_insn (gen_andsi3_i (operands[0], operands[1],
+				   GEN_INT ((1 << (32 - n)) - 1)));
+	  for (; n < 32; n++)
+	    emit_insn (gen_rotrsi3_cnt1 (operands[0], operands[0]));
 	  return;
-	}
-      else if (n >= 29)
-	{
-	  if (n < 31)
-	    {
-	      if (n == 29)
-		{
-		  emit_insn (gen_andsi3_i (operands[0], operands[1],
-					   GEN_INT (7)));
-		  emit_insn (gen_rotrsi3_cnt1 (operands[0], operands[0]));
-		}
-	      else
-		emit_insn (gen_andsi3_i (operands[0], operands[1],
-					 GEN_INT (3)));
-	      emit_insn (gen_rotrsi3_cnt1 (operands[0], operands[0]));
-	    }
-	  else
-	    emit_insn (gen_andsi3_i (operands[0], operands[1], const1_rtx));
-	  emit_insn (gen_rotrsi3_cnt1 (operands[0], operands[0]));
+
+	case SHIFT_AND_SWAP_ROT:
+	  emit_insn (gen_andsi3_i (operands[0], operands[1],
+				   GEN_INT ((1 << (32 - n)) - 1)));
+	  emit_insn (gen_rotrsi2_cnt16 (operands[0], operands[0]));
+	  for (; n < 16; n++)
+	    emit_insn (gen_rotrsi3_cnt1 (operands[0], operands[0]));
 	  return;
+
+	case SHIFT_LOOP:
+	  break;
+
+	default:
+	  gcc_unreachable ();
 	}
     }
 
@@ -5568,6 +5823,37 @@  arc_rtx_costs (rtx x, machine_mode mode, int outer_code,
        If we need more than 12 insns to do a multiply, then go out-of-line,
        since the call overhead will be < 10% of the cost of the multiply.  */
     case ASHIFT:
+      if (mode == DImode)
+	{
+	  if (XEXP (x, 1) == const1_rtx)
+	    {
+	      *total += rtx_cost (XEXP (x, 0), mode, ASHIFT, 0, speed)
+			+ COSTS_N_INSNS (2);
+	      return true;
+	    }
+	  return false;
+	}
+      if (TARGET_BARREL_SHIFTER)
+	{
+	  *total = COSTS_N_INSNS (1);
+	  if (CONST_INT_P (XEXP (x, 1)))
+	    {
+	      *total += rtx_cost (XEXP (x, 0), mode, ASHIFT, 0, speed);
+	      return true;
+	    }
+	}
+      else if (CONST_INT_P (XEXP (x, 1)))
+	{
+	  unsigned int n = INTVAL (XEXP (x, 1)) & 0x1f;
+	  *total = arc_ashl_alg[arc_shift_context_idx ()][n].cost
+		   + rtx_cost (XEXP (x, 0), mode, ASHIFT, 0, speed);
+	  return true;
+	}
+      else
+	/* Variable shift loop takes 2 * n + 2 cycles.  */
+	*total = speed ? COSTS_N_INSNS (64) : COSTS_N_INSNS (4);
+      return false;
+
     case ASHIFTRT:
     case LSHIFTRT:
     case ROTATE: