Add arguments for controlling floating point denormal mode (#7461)

* Implement -fp-denorm-mode slangc arg

* Split fp-denorm-mode into 3 args for fp16/32/64

* Remove redundant option categories

* Use emitInst for multiple of the same OpExecutionMode

* Fix formatting

* Remove -denorm any

* Re-add option categories

* emitinst for ftz

* Use enums for type text

* Remove extra categories again

* Add tests for denorm mode

* Move denorm mode to post linking

* format code (#8)

Co-authored-by: slangbot <186143334+slangbot@users.noreply.github.com>

* regenerate command line reference (#9)

Co-authored-by: slangbot <186143334+slangbot@users.noreply.github.com>

* Clean up tests

* Fix option text

* format code (#10)

Co-authored-by: slangbot <186143334+slangbot@users.noreply.github.com>

* Add tests for "any" mode

* Return "any" enum if option not set

* Simplify emission logic

* Add support for generic entrypoints

* Move denorm modes to end of CompilerOptionName enum

* format code (#11)

Co-authored-by: slangbot <186143334+slangbot@users.noreply.github.com>

* Move new enum members to before CountOf

* Add not checks to tests, fix generic test, add functionality tests

* Rename denorm to fpDenormal

* Clean up functional test

* Rename denorm test dir

* Fix formatting, regenerate cmdline ref

* Fold simple tests into functional tests, add more dxil checks

* Remove no-op DX tests, make tests more consistent

* Disable VK functionality tests that will fail on the CI configs

* Fix formatting

* Add comments to disabled tests explaining why

---------

Co-authored-by: slangbot <ellieh+slangbot@nvidia.com>
Co-authored-by: slangbot <186143334+slangbot@users.noreply.github.com>

2 files changed, 29 insertions, 0 deletions

diff --git a/source/compiler-core/slang-downstream-compiler.h b/source/compiler-core/slang-downstream-compiler.h
index c23a6eff0..6ffcf7aea 100644
--- a/source/compiler-core/slang-downstream-compiler.h
+++ b/source/compiler-core/slang-downstream-compiler.h
@@ -197,6 +197,13 @@ struct DownstreamCompileOptions
         Precise,
     };
 
+    enum class FloatingPointDenormalMode : uint8_t
+    {
+        Any,
+        Preserve,
+        FlushToZero,
+    };
+
     enum PipelineType : uint8_t
     {
         Unknown,
@@ -277,6 +284,11 @@ struct DownstreamCompileOptions
 
     // The debug info format to use.
     SlangDebugInfoFormat m_debugInfoFormat = SLANG_DEBUG_INFO_FORMAT_DEFAULT;
+
+    // The floating point denormal handling mode to use for each floating point precision
+    FloatingPointDenormalMode denormalModeFp16 = FloatingPointDenormalMode::Any;
+    FloatingPointDenormalMode denormalModeFp32 = FloatingPointDenormalMode::Any;
+    FloatingPointDenormalMode denormalModeFp64 = FloatingPointDenormalMode::Any;
 };
 static_assert(std::is_trivially_copyable_v<DownstreamCompileOptions>);
 
@@ -482,6 +494,7 @@ struct DownstreamCompilerUtilBase
     typedef CompileOptions::DebugInfoType DebugInfoType;
 
     typedef CompileOptions::FloatingPointMode FloatingPointMode;
+    typedef CompileOptions::FloatingPointDenormalMode FloatingPointDenormalMode;
 
     typedef DownstreamProductFlag ProductFlag;
     typedef DownstreamProductFlags ProductFlags;
diff --git a/source/compiler-core/slang-dxc-compiler.cpp b/source/compiler-core/slang-dxc-compiler.cpp
index 0d4bc0a59..e27a0fc37 100644
--- a/source/compiler-core/slang-dxc-compiler.cpp
+++ b/source/compiler-core/slang-dxc-compiler.cpp
@@ -512,6 +512,22 @@ SlangResult DXCDownstreamCompiler::compile(const CompileOptions& inOptions, IArt
         break;
     }
 
+    switch (options.denormalModeFp32)
+    {
+    default:
+    case CompileOptions::FloatingPointDenormalMode::Any:
+        break;
+
+    case CompileOptions::FloatingPointDenormalMode::Preserve:
+        args.add(L"-denorm");
+        args.add(L"preserve");
+        break;
+
+    case CompileOptions::FloatingPointDenormalMode::FlushToZero:
+        args.add(L"-denorm");
+        args.add(L"ftz");
+        break;
+    }
 
     switch (options.optimizationLevel)
     {