nir: Unset metadata debug bit if no progress made

NIR metadata validation verifies that the debug bit was unset (by a call
to nir_metadata_preserve) if a NIR optimization pass made progress on
the shader. With the expectation that the NIR shader consists of only a
single main function, it has been safe to call nir_metadata_preserve()
iff progress was made.

However, most optimization passes calculate progress per-function and
then return the union of those calculations. In the case that an
optimization pass makes progress only on a subset of the functions in
the shader metadata validation will detect the debug bit is still set on
any unchanged functions resulting in a failed assertion.

This patch offers a quick solution (short of a larger scale refactoring
which I do not wish to undertake as part of this series) that simply
unsets the debug bit on unchanged functions.

Reviewed-by: Kenneth Graunke <[email protected]>
Reviewed-by: Jason Ekstrand <[email protected]>

1 files changed, 6 insertions, 1 deletions

diff --git a/src/compiler/nir/nir_opt_dead_cf.c b/src/compiler/nir/nir_opt_dead_cf.c
index b547ab600bb..14986732096 100644
--- a/src/compiler/nir/nir_opt_dead_cf.c
+++ b/src/compiler/nir/nir_opt_dead_cf.c
@@ -339,8 +339,13 @@ opt_dead_cf_impl(nir_function_impl *impl)
    bool dummy;
    bool progress = dead_cf_list(&impl->body, &dummy);
 
-   if (progress)
+   if (progress) {
       nir_metadata_preserve(impl, nir_metadata_none);
+    } else {
+#ifndef NDEBUG
+      impl->valid_metadata &= ~nir_metadata_not_properly_reset;
+#endif
+    }
 
    return progress;
 }