Add information about the two DEC C compiler optimizer bugs

(what patch levels of the compilers fix them).

p4raw-id: //depot/cfgperl@3258

diff --git a/pp.c b/pp.c
index d837d4b..8c48574 100644 (file)
--- a/pp.c
+++ b/pp.c
@@ -3677,7 +3677,25 @@ PP(pp_unpack)
 #ifdef __osf__
                     /* Without the dummy below unpack("i", pack("i",-1))
                      * return 0xFFffFFff instead of -1 for Digital Unix V4.0
-                     * cc with optimization turned on */
+                     * cc with optimization turned on.
+                    *
+                    * The bug was detected in
+                    * DEC C V5.8-009 on Digital UNIX V4.0 (Rev. 1091) (V4.0E)
+                    * with optimization (-O4) turned on.
+                    * DEC C V5.2-040 on Digital UNIX V4.0 (Rev. 564) (V4.0B)
+                    * does not have this problem even with -O4.
+                    *
+                    * This bug was reported as DECC_BUGS 1431
+                    * and tracked internally as GEM_BUGS 7775.
+                    *
+                    * The bug is fixed in
+                    * Tru64 UNIX V5.0:      Compaq C V6.1-006 or later
+                    * UNIX V4.0F support:   DEC C V5.9-006 or later
+                    * UNIX V4.0E support:   DEC C V5.8-011 or later
+                    * and also in DTK.
+                    *
+                    * See also few lines later for the same bug.
+                    */
                     (aint) ?
                        sv_setiv(sv, (IV)aint) :
 #endif
@@ -3709,12 +3727,8 @@ PP(pp_unpack)
                    sv = NEWSV(41, 0);
 #ifdef __osf__
                     /* Without the dummy below unpack("I", pack("I",0xFFFFFFFF))
-                     * returns 1.84467440737096e+19 instead of 0xFFFFFFFF for
-                    * DEC C V5.8-009 on Digital UNIX V4.0 (Rev. 1091) (aka V4.0D)
-                    * with optimization turned on.
-                    * (DEC C V5.2-040 on Digital UNIX V4.0 (Rev. 564) (aka V4.0B)
-                    * does not have this problem even with -O4)
-                    */
+                     * returns 1.84467440737096e+19 instead of 0xFFFFFFFF.
+                    * See details few lines earlier. */
                     (auint) ?
                        sv_setuv(sv, (UV)auint) :
 #endif

diff --git a/t/op/repeat.t b/t/op/repeat.t
index f935bf1..c030ba9 100755 (executable)
--- a/t/op/repeat.t
+++ b/t/op/repeat.t
@@ -42,10 +42,15 @@ print join(':', (9,9) x 4) eq '9:9:9:9:9:9:9:9' ? "ok 18\n" : "not ok 18\n";
 print join('', (split(//,"123")) x 2) eq '123123' ? "ok 19\n" : "not ok 19\n";
 
 #
-# The test #20 is actually testing for Digital C compiler optimizer bug.
+# The test #20 is actually testing for Digital C compiler optimizer bug,
+# present in Dec C versions 5.* and 6.0 (used in Digital UNIX and VMS),
+# found in December 1998.  The bug was reported to Digital^WCompaq as
+#     DECC 2745 (21-Dec-1998)
+# GEM_BUGS 7619 (23-Dec-1998)
+# As of April 1999 the bug has been fixed in Tru64 UNIX 5.0 and is planned
+# to be fixed also in 4.0G.
 #
-# Dec C versions 5.* and 6.0 (used in Digital UNIX and VMS) used
-# to produce (as of December 1998) broken code for util.c:repeatcpy()
+# The bug was as follows: broken code was produced for util.c:repeatcpy()
 # (a utility function for the 'x' operator) in the case *all* these
 # four conditions held:
 #
@@ -68,9 +73,6 @@ print join('', (split(//,"123")) x 2) eq '123123' ? "ok 19\n" : "not ok 19\n";
 # 24 .........???????.???????
 # 25 .........???????.???????.
 #
-# The bug could be (obscurely) avoided by changing "from" to
-# be an unsigned char pointer.
-#
 # The bug was triggered in the "if (len == 1)" branch.  The fix
 # was to introduce a new temporary variable.  In diff -u format:
 #
@@ -85,6 +87,9 @@ print join('', (split(//,"123")) x 2) eq '123123' ? "ok 19\n" : "not ok 19\n";
 #        return;
 #     }
 #
+# The bug could also be (obscurely) avoided by changing "from" to
+# be an unsigned char pointer.
+#
 # This obscure bug was not found by the then test suite but instead
 # by Mark.Martinec@nsc.ijs.si while trying to install Digest-MD5-2.00.
 #