diff options
| author | David Mitchell <davem@iabyn.com> | 2016-03-18 22:36:40 +0000 |
|---|---|---|
| committer | David Mitchell <davem@iabyn.com> | 2016-03-18 22:36:40 +0000 |
| commit | 34f817bafdabdc84f560b8d590af294880f66e67 (patch) | |
| tree | 0db840a7fc5b48db6f93201a6130c8f79385accc /regcomp.c | |
| parent | cc93400aa5a8d556c56c28a8de644bd178d050d4 (diff) | |
| download | perl-34f817bafdabdc84f560b8d590af294880f66e67.tar.gz | |
regex sets: fix Solaris optimiser bug (2nd attempt)
[perl #127455]
My first fix for this, (v5.23.7-586-gd9cb841) didn't actually fix it.
The diagnosis was correct, but somewhere during fixing and testing I went
wrong, and the optimiser bug was still being triggered without me spotting
it.
The new approach, based on a suggestion by Tony C, is simply to
declare the errant local var 'fence' to be volatile. This stops the
compiler from optimising away its value.
Diffstat (limited to 'regcomp.c')
| -rw-r--r-- | regcomp.c | 20 |
1 files changed, 4 insertions, 16 deletions
@@ -14547,7 +14547,9 @@ S_handle_regex_sets(pTHX_ RExC_state_t *pRExC_state, SV** return_invlist, 'stack' of where the undealt-with left parens would be if they were actually put there */ - IV fence = 0; /* Position of where most recent undealt- + /* The 'volatile' is a workaround for an optimiser bug + * in Solaris Studio 12.3. See RT #127455 */ + volatile IV fence = 0; /* Position of where most recent undealt- with left paren in stack is; -1 if none. */ STRLEN len; /* Temporary */ @@ -15152,21 +15154,7 @@ redo_curchar: * may have altered the stack in the time since we earlier set * 'top_index'. */ - { - /* Work round an optimiser bug in Solaris Studio 12.3: - * for some reason, the presence of the __assert() in - * av_tindex_nomg() causes the value of fence to get - * corrupted, even though the assert is never called. So - * save the value then restore afterwards. - * Note that in fact merely accessing the value of fence - * prior to the statement containing the assert is enough - * to make the bug go away. - */ - IV f = fence; - top_index = av_tindex_nomg(stack); - fence = f; - } - + top_index = av_tindex_nomg(stack); if (top_index - fence >= 0) { /* If the top entry on the stack is an operator, it had better * be a '!', otherwise the entry below the top operand should |