[dxbc] Set float control bits as necessary

src/dxbc/dxbc_compiler.cpp

@@ -235,6 +235,9 @@ namespace dxvk {
       case DxbcProgramType::PixelShader:    this->emitPsFinalize(); break;
       case DxbcProgramType::ComputeShader:  this->emitCsFinalize(); break;
     }
+
+    // Emit float control mode if the extension is supported
+    this->emitFloatControl();
     
     // Declare the entry point, we now have all the
     // information we need, including the interfaces
@@ -7467,7 +7470,32 @@ namespace dxvk {
     return varId;
   }
   
-  
+
+  void DxbcCompiler::emitFloatControl() {
+    DxbcFloatControlFlags flags = m_moduleInfo.options.floatControl;
+
+    if (flags.isClear())
+      return;
+
+    const uint32_t width32 = 32;
+    const uint32_t width64 = 64;
+
+    m_module.enableExtension("SPV_KHR_float_controls");
+
+    if (flags.test(DxbcFloatControlFlag::DenormFlushToZero32))
+      m_module.setExecutionMode(m_entryPointId, spv::ExecutionModeDenormFlushToZero, 1, &width32);
+
+    if (flags.test(DxbcFloatControlFlag::DenormPreserve64))
+      m_module.setExecutionMode(m_entryPointId, spv::ExecutionModeDenormPreserve, 1, &width64);
+
+    if (flags.test(DxbcFloatControlFlag::PreserveNan32))
+      m_module.setExecutionMode(m_entryPointId, spv::ExecutionModeSignedZeroInfNanPreserve, 1, &width32);
+
+    if (flags.test(DxbcFloatControlFlag::PreserveNan64))
+      m_module.setExecutionMode(m_entryPointId, spv::ExecutionModeSignedZeroInfNanPreserve, 1, &width64);
+  }
+
+
   uint32_t DxbcCompiler::emitNewVariable(const DxbcRegisterInfo& info) {
     const uint32_t ptrTypeId = this->getPointerTypeId(info);
     return m_module.newVar(ptrTypeId, info.sclass);

src/dxbc/dxbc_compiler.h

@@ -1173,6 +1173,8 @@ namespace dxvk {
     
     uint32_t emitSamplePosArray();
     
+    void emitFloatControl();
+    
     ///////////////////////////////
     // Variable definition methods
     uint32_t emitNewVariable(

src/dxbc/dxbc_options.cpp

@@ -57,6 +57,19 @@ namespace dxvk {
     
     // Apply shader-related options
     applyTristate(useSubgroupOpsForEarlyDiscard, device->config().useEarlyDiscard);
+
+    // Figure out float control flags to match D3D11 rules
+    if (devInfo.khrShaderFloatControls.shaderSignedZeroInfNanPreserveFloat32)
+      floatControl.set(DxbcFloatControlFlag::PreserveNan32);
+    if (devInfo.khrShaderFloatControls.shaderSignedZeroInfNanPreserveFloat64)
+      floatControl.set(DxbcFloatControlFlag::PreserveNan64);
+
+    if (devInfo.khrShaderFloatControls.denormBehaviorIndependence != VK_SHADER_FLOAT_CONTROLS_INDEPENDENCE_NONE) {
+      if (devInfo.khrShaderFloatControls.shaderDenormFlushToZeroFloat32)
+        floatControl.set(DxbcFloatControlFlag::DenormFlushToZero32);
+      if (devInfo.khrShaderFloatControls.shaderDenormPreserveFloat64)
+        floatControl.set(DxbcFloatControlFlag::DenormPreserve64);
+    }
   }
   
 }

src/dxbc/dxbc_options.h

@@ -5,7 +5,16 @@
 namespace dxvk {
 
   struct D3D11Options;
-  
+
+  enum class DxbcFloatControlFlag : uint32_t {
+    DenormFlushToZero32,
+    DenormPreserve64,
+    PreserveNan32,
+    PreserveNan64,
+  };
+
+  using DxbcFloatControlFlags = Flags<DxbcFloatControlFlag>;
+
   struct DxbcOptions {
     DxbcOptions();
     DxbcOptions(const Rc<DxvkDevice>& device, const D3D11Options& options);
@@ -48,6 +57,9 @@ namespace dxvk {
     /// Insert memory barriers after TGSM stoes
     bool forceTgsmBarriers = false;
 
+    /// Float control flags
+    DxbcFloatControlFlags floatControl;
+
     /// Minimum storage buffer alignment
     VkDeviceSize minSsboAlignment = 0;
   };

src/spirv/spirv_module.cpp

@@ -93,6 +93,20 @@ namespace dxvk {
   }
   
   
+  void SpirvModule::setExecutionMode(
+          uint32_t                entryPointId,
+          spv::ExecutionMode      executionMode,
+          uint32_t                argCount,
+    const uint32_t*               args) {
+    m_execModeInfo.putIns (spv::OpExecutionMode, 3 + argCount);
+    m_execModeInfo.putWord(entryPointId);
+    m_execModeInfo.putWord(executionMode);
+
+    for (uint32_t i = 0; i < argCount; i++)
+      m_execModeInfo.putWord(args[i]);
+  }
+
+
   void SpirvModule::setInvocations(
           uint32_t                entryPointId,
           uint32_t                invocations) {

src/spirv/spirv_module.h

@@ -86,6 +86,12 @@ namespace dxvk {
             uint32_t                entryPointId,
             spv::ExecutionMode      executionMode);
     
+    void setExecutionMode(
+            uint32_t                entryPointId,
+            spv::ExecutionMode      executionMode,
+            uint32_t                argCount,
+      const uint32_t*               args);
+    
     void setInvocations(
             uint32_t                entryPointId,
             uint32_t                invocations);