Bug #8349: [mingw] adding -mfpmath=sse -msse2 causes segv on Windows 7

• Status: Closed
• Assignee: naruse (Yui NARUSE)
• Target version: 2.1.0
• ruby -v: ruby 2.1.0dev (2013-04-30 trunk 40528) [i386-mingw32]
• Backport: 1.9.3: UNKNOWN, 2.0.0: DONE

[h.shirosaki (Hiroshi Shirosaki)]

I tried -mfpmath=sse -msse2 with mingw on Windows 7 and got 2 segv while make test-all.

Here is the detail.
https://gist.github.com/anonymous/5487498

I don't know why these options causes segv, but adding volatile seems to fix this.
Is this ok to commit?

diff --git a/re.c b/re.c
index fe7e390..5c96276 100644
--- a/re.c
+++ b/re.c
@@ -154,7 +154,8 @@ rb_memsearch_qs(const unsigned char *xs, long m, const unsigned char *ys, long n
{
const unsigned char *x = xs, *xe = xs + m;
const unsigned char *y = ys;

• VALUE i, qstable[256];

• volatile VALUE i;

• VALUE qstable[256];

  /* Preprocessing /
  for (i = 0; i < 256; ++i)
  diff --git a/regcomp.c b/regcomp.c
  index 1373ff2..8c0e2b5 100644
  --- a/regcomp.c
  +++ b/regcomp.c
  @@ -5306,7 +5306,7 @@ set_optimize_exact_info(regex_t reg, OptExactInfo* e)
  static void
  set_optimize_map_info(regex_t* reg, OptMapInfo* m)
  {

• int i;

• volatile int i;

  for (i = 0; i < ONIG_CHAR_TABLE_SIZE; i++)
  reg->map[i] = m->map[i];

[naruse (Yui NARUSE)]

うーん、SSE を使って自動ベクトル化するときに何かバグを踏んでいるんですかねぇ。
objdump か何かでそれぞれの関数を逆アセンブルして貼って頂けませんか。

[phasis68 (Heesob Park)]

I think -mstackrealign flag is the proper solution of this issue.

Refer to
http://www.peterstock.co.uk/games/mingw_sse/
http://gcc.gnu.org/onlinedocs/gcc/i386-and-x86_002d64-Options.html#index-mpc80-1472

[h.shirosaki (Hiroshi Shirosaki)]

• Status changed from Assigned to Closed

phasis68 (Heesob Park) wrote:

I think -mstackrealign flag is the proper solution of this issue.

Refer to
http://www.peterstock.co.uk/games/mingw_sse/
http://gcc.gnu.org/onlinedocs/gcc/i386-and-x86_002d64-Options.html#index-mpc80-1472

Thank you. I'll use -mstackrealign with sse.

I've confirmed that with disassemble.
https://gist.github.com/shirosaki/5488699

[nagachika (Tomoyuki Chikanaga)]

• Backport changed from 1.9.3: UNKNOWN, 2.0.0: UNKNOWN to 1.9.3: UNKNOWN, 2.0.0: DONE

r44539 was already backported into ruby_2_1 at r44993.