[PATCH 06/10] tree-object-size: Support dynamic sizes in conditions
Tue Nov 23 15:12:52 GMT 2021
On Wed, Nov 10, 2021 at 12:31:32AM +0530, Siddhesh Poyarekar wrote:
> (object_sizes_execute): Don't insert min/max for dynamic sizes.
I'm worried about this.
I'd say what we might want to do is in the early pass for __bdos
compute actually __bos (i.e. the static one) and add MIN_EXPR/MAX_EXPR
for the result of the __bdos call from the second pass with the
statically computed value.
The reason for the MIN_EXPR/MAX_EXPR stuff is that GIMPLE optimizations
can remove exact ADDR_EXPRs with detailed COMPONENT_REF etc. access paths
in it, so during the late objsz2 pass the subobject modes don't work
reliably anymore. But the subobject knowledge should be the same between
the static and dynamic evaluation...
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