64067 - mFlags type in nsBlockReflowState tickles Alpha/Linux compiler bug

Status: RESOLVED INVALID

(Core :: Layout, defect)

Description

[msw]

When compiled with -O, the PRInt16 type of mFlags causes some bitfield
operations to fail.  This ultimately causes misrendering (as max element sizes
aren't calculated because the flag doesn't get set properly.)

Changing the type to PRInt32 is the workaround until the compiler is fixed (a
bug is already filed against our gcc, but I don't know when a fixed compiler
will be released.

It is odd, however, that the flags are #defined as 32 bit values, but mFlags is
16 bit...

Comment 1

[msw]

changing platform to DEC

Comment 2

[Christopher Blizzard (:blizzard)]

I think the best solution here is to build a configure test for this and don't
build if the bad compiler is found.  This compiler bug is pretty serious IMHO
and might cause other bugs to crop up.  There's a work around in my rpm.  When
the fixed compiler is released I'll whip up a compiler test.

This only affects RH 7 users on alpha so our risk is relatively minor.

Comment 3

[David Baron :dbaron: (⌚️UTC-4, no longer working on Mozilla)]

Cross-reference to redhat bugzilla bug on gcc:
http://bugzilla.redhat.com/bugzilla/show_bug.cgi?id=23123
(that's the right one, right?)

Comment 4

[Christopher Blizzard (:blizzard)]

New compilers fix this problem.