[Qemu-commits] [qemu/qemu] 7eb30e: tcg/i386: Fix dup_vec in non-AVX2 codepath

[GitHub]

  Branch: refs/heads/master
  Home:   https://github.com/qemu/qemu
  Commit: 7eb30ef0ba2eb59e7430d4848ae8d4bf4e50f768
      
https://github.com/qemu/qemu/commit/7eb30ef0ba2eb59e7430d4848ae8d4bf4e50f768
  Author: Peter Maydell <address@hidden>
  Date:   2018-05-09 (Wed, 09 May 2018)

  Changed paths:
    M tcg/i386/tcg-target.inc.c

  Log Message:
  -----------
  tcg/i386: Fix dup_vec in non-AVX2 codepath

The VPUNPCKLD* instructions are all "non-destructive source",
indicated by "NDS" in the encoding string in the x86 ISA manual.
This means that they take two source operands, one of which is
encoded in the VEX.vvvv field. We were incorrectly treating them
as if they were destructive-source and passing 0 as the 'v'
argument of tcg_out_vex_modrm(). This meant we were always
using %xmm0 as one of the source operands, causing incorrect
results if the register allocator happened to want to use
something else. For instance the input AArch64 insn:
 DUP v26.16b, w21
which becomes TCG IR ops:
 dup_vec v128,e8,tmp2,x21
 st_vec v128,e8,tmp2,env,$0xa40
was assembled to:
0x607c568c:  c4 c1 7a 7e 86 e8 00 00  vmovq    0xe8(%r14), %xmm0
0x607c5694:  00
0x607c5695:  c5 f9 60 c8              vpunpcklbw %xmm0, %xmm0, %xmm1
0x607c5699:  c5 f9 61 c9              vpunpcklwd %xmm1, %xmm0, %xmm1
0x607c569d:  c5 f9 70 c9 00           vpshufd  $0, %xmm1, %xmm1
0x607c56a2:  c4 c1 7a 7f 8e 40 0a 00  vmovdqu  %xmm1, 0xa40(%r14)
0x607c56aa:  00

when the vpunpcklwd insn should be "%xmm1, %xmm1, %xmm1".
This resulted in our incorrectly setting the output vector to
q26=0000320000003200:0000320000003200
when given an input of x21 == 0000000002803200
rather than the expected all-zeroes.

Pass the correct source register number to tcg_out_vex_modrm()
for these insns.

Fixes: 770c2fc7bb70804a
Cc: address@hidden
Signed-off-by: Peter Maydell <address@hidden>
Message-Id: <address@hidden>
Signed-off-by: Richard Henderson <address@hidden>


  Commit: abebf92597186be2bc48d487235da28b1127860f
      
https://github.com/qemu/qemu/commit/abebf92597186be2bc48d487235da28b1127860f
  Author: Richard Henderson <address@hidden>
  Date:   2018-05-09 (Wed, 09 May 2018)

  Changed paths:
    M tcg/tcg.c
    M tcg/tcg.h

  Log Message:
  -----------
  tcg: Limit the number of ops in a TB

In 6001f7729e12 we partially attempt to address the branch
displacement overflow caused by 15fa08f845.

However, gcc/testsuite/gcc.target/aarch64/advsimd-intrinsics/vqtbX.c
is a testcase that contains a TB so large as to overflow anyway.
The limit here of 8000 ops produces a maximum output TB size of
24112 bytes on a ppc64le host with that test case.  This is still
much less than the maximum forward branch distance of 32764 bytes.

Cc: address@hidden
Fixes: 15fa08f845 ("tcg: Dynamically allocate TCGOps")
Reviewed-by: Laurent Vivier <address@hidden>
Reviewed-by: Philippe Mathieu-Daudé <address@hidden>
Signed-off-by: Richard Henderson <address@hidden>


  Commit: 6d7cde809d915e14728eda0af1c0618eb5710a96
      
https://github.com/qemu/qemu/commit/6d7cde809d915e14728eda0af1c0618eb5710a96
  Author: Peter Maydell <address@hidden>
  Date:   2018-05-11 (Fri, 11 May 2018)

  Changed paths:
    M tcg/i386/tcg-target.inc.c
    M tcg/tcg.c
    M tcg/tcg.h

  Log Message:
  -----------
  Merge remote-tracking branch 'remotes/rth/tags/tcg-next-pull-request' into 
staging

Queued TCG patches

# gpg: Signature made Wed 09 May 2018 16:46:21 BST
# gpg:                using RSA key 64DF38E8AF7E215F
# gpg: Good signature from "Richard Henderson <address@hidden>"
# Primary key fingerprint: 7A48 1E78 868B 4DB6 A85A  05C0 64DF 38E8 AF7E 215F

* remotes/rth/tags/tcg-next-pull-request:
  tcg: Limit the number of ops in a TB
  tcg/i386: Fix dup_vec in non-AVX2 codepath

Signed-off-by: Peter Maydell <address@hidden>


Compare: https://github.com/qemu/qemu/compare/5cbc61110738...6d7cde809d91
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