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Re: [tree-ssa] Block merging (updated)
- From: "Zack Weinberg" <zack at codesourcery dot com>
- To: law at redhat dot com
- Cc: Michael Matz <matz at suse dot de>, Zdenek Dvorak <rakdver at atrey dot karlin dot mff dot cuni dot cz>, Steven Bosscher <s dot bosscher at student dot tudelft dot nl>, gcc-patches at gcc dot gnu dot org
- Date: Tue, 13 Jan 2004 11:40:32 -0800
- Subject: Re: [tree-ssa] Block merging (updated)
- References: <200401131914.i0DJEY9G025115@speedy.slc.redhat.com>
law@redhat.com writes:
> I didn't say we have [preserved user labels] forever. I said it is
> policy. There is a subtle, but important difference.
Perhaps it is time to reexamine this policy.
The optimizers tend to move NOTE_INSN_DELETED_LABELs to completely
random locations, so setting breakpoints on the resulting labels does
nothing useful. I'd much rather see "label optimized out" from gdb
than an apparently successful breakpoint which then fails to trigger.
On the other side of it, increasing amounts of special case code to
preserve user labels, interfering with writing optimizations
naturally, is not good.
zw