[Bug target/45233] FAIL: gcc.c-torture/compile/pr44707.c

[iains at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=45233

--- Comment #8 from Iain Sandoe <iains at gcc dot gnu.org> 2011-11-09 10:03:31 UTC ---
well, I was trying to be too complicated - we should just avoid trying to do
the substitution unless we can see the var in the TU.  When this is done:

Index: gcc/config/rs6000/rs6000.c
===================================================================
--- gcc/config/rs6000/rs6000.c  (revision 181150)
+++ gcc/config/rs6000/rs6000.c  (working copy)
@@ -6169,6 +6169,7 @@ rs6000_legitimize_reload_address (rtx x, enum mach
 #if TARGET_MACHO
       && DEFAULT_ABI == ABI_DARWIN
       && (flag_pic || MACHO_DYNAMIC_NO_PIC_P)
+      && machopic_symbol_defined_p (x)
 #else
       && DEFAULT_ABI == ABI_V4
       && !flag_pic

.. the test-case generates beautiful (i.e. what one would have generated by
hand) asm.

reg-strapped on trunk (although there's a lot of noise on trunk right now
because of recent changes) 
- doing 4.6 branch now.

will post to patches if the 4.6 regstrap is also OK.

====

As an aside (non-Darwin comment - since powerpc-eabisim does exactly the same).

It's not obvious why the perfectly sensible RTL pre-combine is thrown away and
the process started over (I'm guessing it's because the asm insn has a zero
computed cost).  Effectively (to my untutored eye), we end up rebuilding what
was there before combine from the reload ...