[ghost@example.com: Correction re: Compiling Aladdin Ghostscript with gcc 2.7.x]

[turnbull@example.com (Stephen J. Turnbull)]

For those of you with bleeding edge systems, there's a warning out on
Ghostscript and GCC 2.7.x.  "Aladdin Ghostscript" basically refers to
versions more recent than 3.33.  For those of you who don't know,
L. Peter Deutsch is the  "ghost" in "Ghostscript".  So this is
authoritative.

I don't know what else that bug might affect, it looks pretty nasty.

Steve

> X-btw: vix.com is also gw.home.vix.com and vixie.sf.ca.us
> Date: Fri, 15 Mar 96 14:55 PST
> From: ghost@example.com (L. Peter Deutsch)
> To: comp.lang.postscript@example.com, gs-beta@example.com

In an e-mail earlier today, I said that gcc 2.7.0 and 2.7.1 had an optimizer
bug that caused them to compile Aladdin Ghostscript incorrectly, and that
the bug was fixed in gcc 2.7.2.  Unfortunately, this is wrong: the bug is
not fixed in gcc 2.7.2, which is the most recent gcc release.  Therefore,

	DO NOT ATTEMPT TO COMPILE Aladdin Ghostscript WITH gcc 2.7.x
	UNLESS YOU ARE PREPARED TO REBUILD gcc WITH THE PATCH FIRST.

I have enclosed the patch at the end of this message for those who want to
rebuild gcc.  Meanwhile, I suggest that if you have gcc 2.7.x, you replace
it with gcc 2.6.3.

L. Peter Deutsch          |       Aladdin Enterprises :::: ghost@example.com
203 Santa Margarita Ave.  | tel. +1-415-322-0103 (AM only); fax +1-415-322-1734
Menlo Park, CA 94025      |  -&-  Artifex Software Inc. :: tech@example.com
          "Implementation is the sincerest form of flattery."


*** clean-ss-951203/expr.c	Sun Nov 26 08:18:07 1995
--- ss-951203/expr.c	Mon Dec  4 11:41:18 1995
*************** expand_expr (exp, target, tmode, modifie
*** 4582,4588 ****
  	   through a pointer to const does not mean that the value there can
  	   never change.  Languages where it can never change should
  	   also set TREE_STATIC.  */
! 	RTX_UNCHANGING_P (temp) = TREE_READONLY (exp) | TREE_STATIC (exp);
  	return temp;
        }
  
--- 4582,4588 ----
  	   through a pointer to const does not mean that the value there can
  	   never change.  Languages where it can never change should
  	   also set TREE_STATIC.  */
! 	RTX_UNCHANGING_P (temp) = TREE_READONLY (exp) & TREE_STATIC (exp);
  	return temp;
        }