Implement discard semantics
Implement new transform UnwindDiscardFunctions that replaces discard
statements with setting a module-level bool, adds a check and return for
this bool after every function call that may discard, and finally
invokes a single function that executes a discard from top-level
functions.
Regenerated tests and remove HLSL ones that used to fail FXC because it
had difficulty with discard.
Bug: tint:1478
Bug: chromium:1118
Change-Id: I09d680f59e2d5d0cad907bfbbdd426aae76d4bf3
Reviewed-on: https://dawn-review.googlesource.com/c/tint/+/84221
Reviewed-by: James Price <jrprice@google.com>
Reviewed-by: Ben Clayton <bclayton@google.com>
Kokoro: Kokoro <noreply+kokoro@google.com>
Commit-Queue: Antonio Maiorano <amaiorano@google.com>
diff --git a/src/tint/writer/hlsl/generator_impl.cc b/src/tint/writer/hlsl/generator_impl.cc
index 909fcff..bf35449 100644
--- a/src/tint/writer/hlsl/generator_impl.cc
+++ b/src/tint/writer/hlsl/generator_impl.cc
@@ -62,6 +62,7 @@
#include "src/tint/transform/remove_phonies.h"
#include "src/tint/transform/simplify_pointers.h"
#include "src/tint/transform/unshadow.h"
+#include "src/tint/transform/unwind_discard_functions.h"
#include "src/tint/transform/zero_init_workgroup_memory.h"
#include "src/tint/utils/defer.h"
#include "src/tint/utils/map.h"
@@ -187,6 +188,7 @@
// only accessed directly via member accessors.
manager.Add<transform::NumWorkgroupsFromUniform>();
manager.Add<transform::PromoteSideEffectsToDecl>();
+ manager.Add<transform::UnwindDiscardFunctions>();
manager.Add<transform::SimplifyPointers>();
manager.Add<transform::RemovePhonies>();
// ArrayLengthFromUniform must come after InlinePointerLets and Simplify, as
