[Bug target/63724] New: [AArch64] Inefficient immediate expansion and hoisting.

[Bug target/63724] New: [AArch64] Inefficient immediate expansion and hoisting.

[ramana at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=63724

            Bug ID: 63724
           Summary: [AArch64] Inefficient immediate expansion and
                    hoisting.
           Product: gcc
           Version: unknown
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: target
          Assignee: unassigned at gcc dot gnu.org
          Reporter: ramana at gcc dot gnu.org

For some cases like hmmer in SPEC2k6 we currently generate pretty rubbish code
with AArch64. 

float
P7Viterbi(int **mmx, int L, int M, int **imx, int **dmx)
{
  int k;

  for (k = 0; k <= M; k++)
    mmx[0][k] = imx[0][k] = dmx[0][k] = -987654321;

}

This ends up generating pretty rubbish code at O2. 

tbnz    w2, #31, .L4
    ldr    x5, [x3]
    ldr    x4, [x4]
    ldr    x6, [x0]
    mov    x0, 0
.L3:
    mov    w1, 38735
    mov    w3, w1
    movk    w1, 0xc521, lsl 16
    str    w1, [x4, x0, lsl 2]
    movk    w3, 0xc521, lsl 16
    mov    w1, 38735
    str    w3, [x5, x0, lsl 2]
    movk    w1, 0xc521, lsl 16
    str    w1, [x6, x0, lsl 2]
    add    x0, x0, 1
    cmp    w2, w0
    bge    .L3
.L4:
    fmov    s0, wzr
    ret
    .size    P7Viterbi, .-P7Viterbi

and could well be 


P7Viterbi:
        tbnz    w2, #31, .L4
        ldr     x5, [x3]
        mov     w1, 38735
        ldr     x3, [x4]
        movk    w1, 0xc521, lsl 16
        ldr     x6, [x0]
        mov     x0, 0
.L3:
        str     w1, [x3, x0, lsl 2]
        str     w1, [x5, x0, lsl 2]
        str     w1, [x6, x0, lsl 2]
        add     x0, x0, 1
        cmp     w2, w0
        bge     .L3
.L4:
        fmov    s0, wzr
        ret
        .size   P7Viterbi, .-P7Viterbi

The hoisting is missed because we expand const_int's too early in the AArch64
backend. Given we don't have an "uncse" in the mid-end it's quite hard to
recover when we've expanded to this form rather early in the compiler. The
simple solution is just to move the logic out into a separate splitter
function, additionally we should also investigate what happens if we start
doing the same for our address computations, but that's the subject of a
separate patch. 

Mine.

[Bug target/63724] [AArch64] Inefficient immediate expansion and hoisting.

[ramana at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=63724

Ramana Radhakrishnan <ramana at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Keywords|                            |missed-optimization
             Target|                            |aarch64-linux-gnu
             Status|UNCONFIRMED                 |ASSIGNED
   Last reconfirmed|                            |2014-11-03
           Assignee|unassigned at gcc dot gnu.org      |ramana at gcc dot gnu.org
   Target Milestone|---                         |5.0
     Ever confirmed|0                           |1

--- Comment #1 from Ramana Radhakrishnan <ramana at gcc dot gnu.org> ---
Mine.

[Bug target/63724] [AArch64] Inefficient immediate expansion and hoisting.

[ramana at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=63724

Ramana Radhakrishnan <ramana at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|ASSIGNED                    |RESOLVED
         Resolution|---                         |FIXED

--- Comment #2 from Ramana Radhakrishnan <ramana at gcc dot gnu.org> ---
Fixed by r217546

[Bug target/63724] [AArch64] Inefficient immediate expansion and hoisting.

[ramana at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=63724

--- Comment #3 from Ramana Radhakrishnan <ramana at gcc dot gnu.org> ---
Author: ramana
Revision: 217546
Modified property: svn:log

Modified: svn:log at Fri Nov 14 11:03:00 2014
------------------------------------------------------------------------------
--- svn:log (original)
+++ svn:log Fri Nov 14 11:03:00 2014
@@ -1,1 +1,14 @@
-Fix typo in *<arith_shift_insn>_shiftsi
+Fix PR target/63724
+
+2014-11-14  Ramana Radhakrishnan  <ramana.radhakrishnan@arm.com>
+
+    PR target/63724
+        * config/aarch64/aarch64.c (aarch64_expand_mov_immediate): Split out
+        numerical immediate handling to...
+        (aarch64_internal_mov_immediate): ...this. New.
+        (aarch64_rtx_costs): Use aarch64_internal_mov_immediate.
+        (aarch64_mov_operand_p): Relax predicate.
+        * config/aarch64/aarch64.md (mov<mode>:GPI): Do not expand CONST_INTs.
+        (*movsi_aarch64): Turn into define_insn_and_split and new alternative
+        for 'n'.
+        (*movdi_aarch64): Likewise.

[Bug target/63724] [AArch64] Inefficient immediate expansion and hoisting.

[yroux at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=63724

--- Comment #4 from Yvan Roux <yroux at gcc dot gnu.org> ---
Author: yroux
Date: Sun Jan 11 18:36:42 2015
New Revision: 219433

URL: https://gcc.gnu.org/viewcvs?rev=219433&root=gcc&view=rev
Log:
gcc/
2015-01-11  Yvan Roux  <yvan.roux@linaro.org>

    Backport from trunk r217362, r217546.
    2014-11-14  Ramana Radhakrishnan  <ramana.radhakrishnan@arm.com>

    PR target/63724
        * config/aarch64/aarch64.c (aarch64_expand_mov_immediate): Split out
        numerical immediate handling to...
        (aarch64_internal_mov_immediate): ...this. New.
        (aarch64_rtx_costs): Use aarch64_internal_mov_immediate.
        (aarch64_mov_operand_p): Relax predicate.
        * config/aarch64/aarch64.md (mov<mode>:GPI): Do not expand CONST_INTs.
        (*movsi_aarch64): Turn into define_insn_and_split and new alternative
        for 'n'.
        (*movdi_aarch64): Likewise.

    2014-11-11  James Greenhalgh  <james.greenhalgh@arm.com>

    * config/aarch64/aarch64-simd.md
    (aarch64_simd_bsl<mode>_internal): Remove float cases, canonicalize.
    (aarch64_simd_bsl<mode>): Add gen_lowpart expressions where we
    are punning between float vectors and integer vectors.

gcc/testsuite
2015-01-11  Yvan Roux  <yvan.roux@linaro.org>

    Backport from trunk r217362.
    2014-11-11  James Greenhalgh  <james.greenhalgh@arm.com>

    * gcc.target/aarch64/vbslq_f64_1.c: New.
    * gcc.target/aarch64/vbslq_f64_2.c: Likewise.
    * gcc.target/aarch64/vbslq_u64_1.c: Likewise.
    * gcc.target/aarch64/vbslq_u64_2.c: Likewise.


Added:
   
branches/linaro/gcc-4_9-branch/gcc/testsuite/gcc.target/aarch64/vbslq_f64_1.c
   
branches/linaro/gcc-4_9-branch/gcc/testsuite/gcc.target/aarch64/vbslq_f64_2.c
   
branches/linaro/gcc-4_9-branch/gcc/testsuite/gcc.target/aarch64/vbslq_u64_1.c
   
branches/linaro/gcc-4_9-branch/gcc/testsuite/gcc.target/aarch64/vbslq_u64_2.c
Modified:
    branches/linaro/gcc-4_9-branch/gcc/ChangeLog.linaro
    branches/linaro/gcc-4_9-branch/gcc/config/aarch64/aarch64-simd.md
    branches/linaro/gcc-4_9-branch/gcc/config/aarch64/aarch64.c
    branches/linaro/gcc-4_9-branch/gcc/config/aarch64/aarch64.md
    branches/linaro/gcc-4_9-branch/gcc/testsuite/ChangeLog.linaro