[PATCH] Fix PR69951
Mon Feb 29 17:36:00 GMT 2016
On Fri, Feb 26, 2016 at 09:32:53AM +0100, Richard Biener wrote:
> The following fixes PR69951, hopefully the last case of decl alias
> issues with alias analysis. This time it's points-to and the DECL_UIDs
> used in points-to sets not being canonicalized.
> The simplest (and cheapest) fix is to make aliases refer to the
> ultimate alias target via their DECL_PT_UID which we conveniently
> have available.
> Bootstrapped and tested on x86_64-unknown-linux-gnu, applied to trunk.
> 2016-02-26 Richard Biener <firstname.lastname@example.org>
> PR tree-optimization/69551
> * tree-ssa-structalias.c (get_constraint_for_ssa_var): When
> looking through aliases adjust DECL_PT_UID to refer to the
> ultimate alias target.
> * gcc.dg/torture/pr69951.c: New testcase.
I see this new testcase failing on an ARM target as so:
/tmp/ccChjoFc.s: Assembler messages:
/tmp/ccChjoFc.s:21: Warning: [-mwarn-syms]: Assignment makes a symbol match an ARM instruction: b
FAIL: gcc.dg/torture/pr69951.c -O0 (test for excess errors)
But I haven't managed to reproduce it outside of the test environment.
The fix looks trivial, rename b to anything else you fancy (well... stay
clear of add and ldr). I'll put a fix in myself if I can manage to get
this to reproduce - though if anyone else wants to do it I won't be
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