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Re: [RFD] MIPS/gas: Optimisation cannot be set to 0
Ian Lance Taylor wrote:
> "Maciej W. Rozycki" <firstname.lastname@example.org> writes:
> > Wed Feb 12 14:36:29 1997 Ian Lance Taylor <email@example.com>
> > * config/tc-mips.c (md_parse_option): When debugging, set
> > mips_optimize to 1, not 0.
> My vague recollection of the problem is that at least at that time gcc
> would always pass a -O option to the assembler. When not optimizing,
> it would pass -O0. However, inserting NOPs for MIPS variants which do
> not need them does not help debugging.
> Clearly failing to provide a way to set mips_optimize to 0 was an
> > I have no strong preference, but I think gas should have a mode where its
> > input is assembled intact. And swapping branches may produce surprising
> > interactions with debugging information. I am therefore in favour to the
> > first proposal above, but I would like to hear from the others.
> I'm not sure I see the relevance of "assembled intact." The source is
> assembled just as the user specified with -O1. -O1 simply inhibits
> adding additional unnecessary nop instructions--nop instructions that
> were required for MIPS ISA I but not for later ISAs.
> At -O1 branches are not swapped, so debugging is not impaired.
> I agree there should be a way to set mips_optimize to 0, but we should
> ensure that gcc -O0 does not set mips_optimize to 0 when assembling.
I plan to commit the appended patch to fix this. Comments?
2007-11-14 Thiemo Seufer <firstname.lastname@example.org>
* config/tc-mips.c (md_parse_option): Match mips_optimize to the -O
option supplied, but still keep mips_optimize == 2 as default value.
--- head.orig/gas/config/tc-mips.c 2007-11-14 17:41:58.000000000 +0000
+++ head/gas/config/tc-mips.c 2007-11-14 17:51:43.000000000 +0000
@@ -11013,7 +11013,11 @@
- if (arg && arg == '0')
+ if (arg == NULL)
+ mips_optimize = 1;
+ else if (arg == '0')
+ mips_optimize = 0;
+ else if (arg == '1')
mips_optimize = 1;
mips_optimize = 2;