[DirectX] Set shader feature flags MinimumPrecision and NativeLowPrecision, and refactor the logic for setting low-precision-related flags

llvm/lib/Target/DirectX/DXILShaderFlags.cpp

@@ -296,6 +296,14 @@ void ModuleShaderFlags::initialize(Module &M, DXILResourceTypeMap &DRTM,
   if (NumUAVs > 8)
     CombinedSFMask.Max64UAVs = true;
 
+  // Set the Shader Feature Info flags related to low-precision datatypes
+  if (CombinedSFMask.LowPrecisionPresent) {
+    if (CombinedSFMask.UseNativeLowPrecision)
+      CombinedSFMask.NativeLowPrecision = true;
+    else
+      CombinedSFMask.MinimumPrecision = true;
+  }
+
   CombinedSFMask.UAVsAtEveryStage = hasUAVsAtEveryStage(DRM, MMDI);
 }
 

llvm/test/CodeGen/DirectX/ShaderFlags/low-precision.ll

@@ -1,30 +1,44 @@
 ; RUN: opt -S --passes="print-dx-shader-flags" 2>&1 %s | FileCheck %s
+; RUN: llc %s --filetype=obj -o - | obj2yaml | FileCheck %s --check-prefix=DXC
+
+; Check that when the dx.nativelowprec module flag is not specified, the
+; module-level shader flag UseNativeLowPrecision is not set, and the
+; MinimumPrecision feature flag is set due to the presence of half and i16
+; without native low precision.
 
 target triple = "dxil-pc-shadermodel6.7-library"
 
 ;CHECK: ; Combined Shader Flags for Module
 ;CHECK-NEXT: ; Shader Flags Value: 0x00000020
 ;CHECK-NEXT: ;
 ;CHECK-NEXT: ; Note: shader requires additional functionality:
+;CHECK-NEXT: ;       Minimum-precision data types
 ;CHECK-NEXT: ; Note: extra DXIL module flags:
 ;CHECK-NEXT: ;       Low-precision data types
 ;CHECK-NEXT: ;
 ;CHECK-NEXT: ; Shader Flags for Module Functions
 
 ;CHECK-LABEL: ; Function add_i16 : 0x00000020
-define i16 @add_i16(i16 %a, i16 %b) {
+define i16 @add_i16(i16 %a, i16 %b) "hlsl.export" {
   %sum = add i16 %a, %b
   ret i16 %sum
 }
 
 ;CHECK-LABEL: ; Function add_i32 : 0x00000000
-define i32 @add_i32(i32 %a, i32 %b) {
+define i32 @add_i32(i32 %a, i32 %b) "hlsl.export" {
   %sum = add i32 %a, %b
   ret i32 %sum
 }
 
 ;CHECK-LABEL: ; Function add_half : 0x00000020
-define half @add_half(half %a, half %b) {
+define half @add_half(half %a, half %b) "hlsl.export" {
   %sum = fadd half %a, %b
   ret half %sum
 }
+
+; DXC: - Name:            SFI0
+; DXC-NEXT:     Size:            8
+; DXC-NEXT:     Flags:
+; DXC:      MinimumPrecision: true
+; DXC:      NativeLowPrecision: false
+; DXC: ...

llvm/test/CodeGen/DirectX/ShaderFlags/use-native-low-precision-0.ll

@@ -1,37 +1,47 @@
 ; RUN: opt -S --passes="print-dx-shader-flags" 2>&1 %s | FileCheck %s
+; RUN: llc %s --filetype=obj -o - | obj2yaml | FileCheck %s --check-prefix=DXC
 
 ; Check that when the dx.nativelowprec module flag is set to 0, the module-level
-; shader flag UseNativeLowPrecision is not set
+; shader flag UseNativeLowPrecision is not set, and the MinimumPrecision feature
+; flag is set due to the presence of half and i16 without native low precision.
 
 target triple = "dxil-pc-shadermodel6.7-library"
 
 ;CHECK: ; Combined Shader Flags for Module
 ;CHECK-NEXT: ; Shader Flags Value: 0x00000020
 ;CHECK-NEXT: ;
 ;CHECK-NEXT: ; Note: shader requires additional functionality:
+;CHECK-NEXT: ;       Minimum-precision data types
 ;CHECK-NEXT: ; Note: extra DXIL module flags:
 ;CHECK-NEXT: ;       Low-precision data types
 ;CHECK-NOT:  ;       Native 16bit types enabled
 ;CHECK-NEXT: ;
 ;CHECK-NEXT: ; Shader Flags for Module Functions
 
 ;CHECK-LABEL: ; Function add_i16 : 0x00000020
-define i16 @add_i16(i16 %a, i16 %b) {
+define i16 @add_i16(i16 %a, i16 %b) "hlsl.export" {
   %sum = add i16 %a, %b
   ret i16 %sum
 }
 
 ;CHECK-LABEL: ; Function add_i32 : 0x00000000
-define i32 @add_i32(i32 %a, i32 %b) {
+define i32 @add_i32(i32 %a, i32 %b) "hlsl.export" {
   %sum = add i32 %a, %b
   ret i32 %sum
 }
 
 ;CHECK-LABEL: ; Function add_half : 0x00000020
-define half @add_half(half %a, half %b) {
+define half @add_half(half %a, half %b) "hlsl.export" {
   %sum = fadd half %a, %b
   ret half %sum
 }
 
 !llvm.module.flags = !{!0}
 !0 = !{i32 1, !"dx.nativelowprec", i32 0}
+
+; DXC: - Name:            SFI0
+; DXC-NEXT:     Size:            8
+; DXC-NEXT:     Flags:
+; DXC:      MinimumPrecision: true
+; DXC:      NativeLowPrecision: false
+; DXC: ...

llvm/test/CodeGen/DirectX/ShaderFlags/use-native-low-precision-1.ll

@@ -1,19 +1,25 @@
 ; RUN: opt -S --passes="print-dx-shader-flags" 2>&1 %s | FileCheck %s
+; RUN: llc %s --filetype=obj -o - | obj2yaml | FileCheck %s --check-prefix=DXC
+
+; Check that when the dx.nativelowprec module flag is set to 1, the module-level
+; shader flag UseNativeLowPrecision is set, and the NativeLowPrecision feature
+; flag is set
 
 target triple = "dxil-pc-shadermodel6.7-library"
 
 ;CHECK: ; Combined Shader Flags for Module
 ;CHECK-NEXT: ; Shader Flags Value: 0x00800020
 ;CHECK-NEXT: ;
 ;CHECK-NEXT: ; Note: shader requires additional functionality:
+;CHECK-NEXT: ;       Use native low precision
 ;CHECK-NEXT: ; Note: extra DXIL module flags:
 ;CHECK-NEXT: ;       Low-precision data types
 ;CHECK-NEXT: ;       Use native low precision
 ;CHECK-NEXT: ;
 ;CHECK-NEXT: ; Shader Flags for Module Functions
 
 ;CHECK-LABEL: ; Function add_i16 : 0x00800020
-define i16 @add_i16(i16 %a, i16 %b) {
+define i16 @add_i16(i16 %a, i16 %b) "hlsl.export" {
   %sum = add i16 %a, %b
   ret i16 %sum
 }
@@ -22,16 +28,23 @@ define i16 @add_i16(i16 %a, i16 %b) {
 ; in the module regardless of whether or not the function uses low precision
 ; data types (flag 0x20). This matches the behavior in DXC
 ;CHECK-LABEL: ; Function add_i32 : 0x00800000
-define i32 @add_i32(i32 %a, i32 %b) {
+define i32 @add_i32(i32 %a, i32 %b) "hlsl.export" {
   %sum = add i32 %a, %b
   ret i32 %sum
 }
 
 ;CHECK-LABEL: ; Function add_half : 0x00800020
-define half @add_half(half %a, half %b) {
+define half @add_half(half %a, half %b) "hlsl.export" {
   %sum = fadd half %a, %b
   ret half %sum
 }
 
 !llvm.module.flags = !{!0}
 !0 = !{i32 1, !"dx.nativelowprec", i32 1}
+
+; DXC: - Name:            SFI0
+; DXC-NEXT:     Size:            8
+; DXC-NEXT:     Flags:
+; DXC:      MinimumPrecision: false
+; DXC:      NativeLowPrecision: true
+; DXC: ...