If an ir_loop has a non-null "counter" field, the variable referred to
by this field is implicitly read and written by the loop. We need to
account for this in ir_variable_refcount, otherwise there is a danger
we will try to dead-code-eliminate the loop counter variable.
Note: at the moment the dead code elimination bug doesn't occur due to
a bug in ir_hierarchical_visitor: it doesn't visit the "counter"
field, so dead code elimination doesn't treat it as a candidate for
elimination. But the patch to follow will fix that bug, so we need to
fix ir_variable_refcount first in order to avoid breaking dead code
elimination.
Reviewed-by: Eric Anholt <eric@anholt.net>
Reviewed-by: Kenneth Graunke <kenneth@whitecape.org>
(cherry picked from commit 9d2951ea0a)
Exporting a publicly visible class with a generic name like
"variable_entry" via ir_variable_refcount.h is kind of mean.
Many IR transformers would like to define their own "variable_entry"
class. If they accidentally include this header, the compiler/linker
may get confused and try to instantiate the wrong variable_entry class,
leading to bizarre runtime crashes.
The hope is that renaming this one will allow .cpp files to safely
declare and use their own file-scope "variable_entry" classes.
This avoids crashes caused by converting src/glsl to automake.
Signed-off-by: Kenneth Graunke <kenneth@whitecape.org>
Reviewed-and-tested-by: Matt Turner <mattst88@gmail.com>
Reviewed-by: Eric Anholt <eric@anholt.net>
A variable_entry after construction should have its referenced_count
member set to 0. However, occassionally this isn't the case and
entry->referenced_count has been observed to be a garbage value. This
leads to crashes of several tests in the Piglit test suite.
This patch adds an assert to check that a variable_entry instance has
its referenced_count member initialized to 0 after construction.
