AMDGPU: Add default denormal mode to MachineFunctionInfo

The default FP mode should really be a property of a specific
function, and not a subtarget. Introduce the necessary fields to the
SIMachineFunctionInfo to help move towards this goal.

3 files changed, 33 insertions, 6 deletions

diff --git a/llvm/lib/Target/AMDGPU/AMDGPUTargetMachine.cpp b/llvm/lib/Target/AMDGPU/AMDGPUTargetMachine.cpp
index e8cf77161a1..64739cd15c8 100644
--- a/llvm/lib/Target/AMDGPU/AMDGPUTargetMachine.cpp
+++ b/llvm/lib/Target/AMDGPU/AMDGPUTargetMachine.cpp
@@ -1151,6 +1151,8 @@ bool GCNTargetMachine::parseMachineFunctionInfo(
 
   MFI->Mode.IEEE = YamlMFI.Mode.IEEE;
   MFI->Mode.DX10Clamp = YamlMFI.Mode.DX10Clamp;
+  MFI->Mode.FP32Denormals = YamlMFI.Mode.FP32Denormals;
+  MFI->Mode.FP64FP16Denormals = YamlMFI.Mode.FP64FP16Denormals;
 
   return false;
 }
diff --git a/llvm/lib/Target/AMDGPU/SIMachineFunctionInfo.h b/llvm/lib/Target/AMDGPU/SIMachineFunctionInfo.h
index 7d70c786b59..0d6153d06ce 100644
--- a/llvm/lib/Target/AMDGPU/SIMachineFunctionInfo.h
+++ b/llvm/lib/Target/AMDGPU/SIMachineFunctionInfo.h
@@ -236,17 +236,23 @@ template <> struct MappingTraits<SIArgumentInfo> {
 struct SIMode {
   bool IEEE = true;
   bool DX10Clamp = true;
+  bool FP32Denormals = true;
+  bool FP64FP16Denormals = true;
 
   SIMode() = default;
 
-
   SIMode(const AMDGPU::SIModeRegisterDefaults &Mode) {
     IEEE = Mode.IEEE;
     DX10Clamp = Mode.DX10Clamp;
+    FP32Denormals = Mode.FP32Denormals;
+    FP64FP16Denormals = Mode.FP64FP16Denormals;
   }
 
   bool operator ==(const SIMode Other) const {
-    return IEEE == Other.IEEE && DX10Clamp == Other.DX10Clamp;
+    return IEEE == Other.IEEE &&
+           DX10Clamp == Other.DX10Clamp &&
+           FP32Denormals == Other.FP32Denormals &&
+           FP64FP16Denormals == Other.FP64FP16Denormals;
   }
 };
 
@@ -254,6 +260,8 @@ template <> struct MappingTraits<SIMode> {
   static void mapping(IO &YamlIO, SIMode &Mode) {
     YamlIO.mapOptional("ieee", Mode.IEEE, true);
     YamlIO.mapOptional("dx10-clamp", Mode.DX10Clamp, true);
+    YamlIO.mapOptional("fp32-denormals", Mode.FP32Denormals, true);
+    YamlIO.mapOptional("fp64-fp16-denormals", Mode.FP64FP16Denormals, true);
   }
 };
 
diff --git a/llvm/lib/Target/AMDGPU/Utils/AMDGPUBaseInfo.h b/llvm/lib/Target/AMDGPU/Utils/AMDGPUBaseInfo.h
index f78dadd447f..f8c082060ff 100644
--- a/llvm/lib/Target/AMDGPU/Utils/AMDGPUBaseInfo.h
+++ b/llvm/lib/Target/AMDGPU/Utils/AMDGPUBaseInfo.h
@@ -659,23 +659,40 @@ struct SIModeRegisterDefaults {
   /// clamp NaN to zero; otherwise, pass NaN through.
   bool DX10Clamp : 1;
 
-  // TODO: FP mode fields
+  /// If this is set, neither input or output denormals are flushed for most f32
+  /// instructions.
+  ///
+  /// TODO: Split into separate input and output fields if necessary like the
+  /// control bits really provide?
+  bool FP32Denormals : 1;
+
+  /// If this is set, neither input or output denormals are flushed for both f64
+  /// and f16/v2f16 instructions.
+  bool FP64FP16Denormals : 1;
 
   SIModeRegisterDefaults() :
     IEEE(true),
-    DX10Clamp(true) {}
+    DX10Clamp(true),
+    FP32Denormals(true),
+    FP64FP16Denormals(true) {}
 
   SIModeRegisterDefaults(const Function &F);
 
   static SIModeRegisterDefaults getDefaultForCallingConv(CallingConv::ID CC) {
+    const bool IsCompute = AMDGPU::isCompute(CC);
+
     SIModeRegisterDefaults Mode;
     Mode.DX10Clamp = true;
-    Mode.IEEE = AMDGPU::isCompute(CC);
+    Mode.IEEE = IsCompute;
+    Mode.FP32Denormals = false; // FIXME: Should be on by default.
+    Mode.FP64FP16Denormals = true;
     return Mode;
   }
 
   bool operator ==(const SIModeRegisterDefaults Other) const {
-    return IEEE == Other.IEEE && DX10Clamp == Other.DX10Clamp;
+    return IEEE == Other.IEEE && DX10Clamp == Other.DX10Clamp &&
+           FP32Denormals == Other.FP32Denormals &&
+           FP64FP16Denormals == Other.FP64FP16Denormals;
   }
 
   // FIXME: Inlining should be OK for dx10-clamp, since the caller's mode should