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[SPIRV][HLSL] map lerp to Fmix #88976

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merged 3 commits into from
Apr 22, 2024
Merged

[SPIRV][HLSL] map lerp to Fmix #88976

merged 3 commits into from
Apr 22, 2024

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farzonl
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@farzonl farzonl commented Apr 16, 2024

  • clang/lib/CodeGen/CGBuiltin.cpp - switch to using getLerpIntrinsic() to abstract backend intrinsic
  • clang/lib/CodeGen/CGHLSLRuntime.h - add getLerpIntrinsic()
  • llvm/include/llvm/IR/IntrinsicsSPIRV.td - add SPIRV intrinsic for lerp
  • llvm/lib/Target/SPIRV/SPIRVInstructionSelector.cpp - add mapping of HLSL's lerp to GLSL's Fmix.

resolves #88940

@farzonl farzonl self-assigned this Apr 16, 2024
@llvmbot llvmbot added clang Clang issues not falling into any other category clang:codegen HLSL HLSL Language Support backend:SPIR-V llvm:ir labels Apr 16, 2024
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llvmbot commented Apr 16, 2024 •
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@llvm/pr-subscribers-clang
@llvm/pr-subscribers-backend-spir-v
@llvm/pr-subscribers-hlsl

@llvm/pr-subscribers-llvm-ir

Author: Farzon Lotfi (farzonl)

Changes
  • clang/lib/CodeGen/CGBuiltin.cpp - switch to using getLerpIntrinsic() to abstract backend intrinsic
  • clang/lib/CodeGen/CGHLSLRuntime.h - add getLerpIntrinsic()
  • llvm/include/llvm/IR/IntrinsicsSPIRV.td - add SPIRV intrinsic for lerp
  • llvm/lib/Target/SPIRV/SPIRVInstructionSelector.cpp - add mapping of HLSL's lerp to GLSL's Fmix.

resolves #88940

Full diff: https://github.com/llvm/llvm-project/pull/88976.diff

6 Files Affected:

  • (modified) clang/lib/CodeGen/CGBuiltin.cpp (+2-2)
  • (modified) clang/lib/CodeGen/CGHLSLRuntime.h (+1)
  • (modified) clang/test/CodeGenHLSL/builtins/lerp.hlsl (+60-36)
  • (modified) llvm/include/llvm/IR/IntrinsicsSPIRV.td (+2)
  • (modified) llvm/lib/Target/SPIRV/SPIRVInstructionSelector.cpp (+26)
  • (added) llvm/test/CodeGen/SPIRV/hlsl-intrinsics/lerp.ll (+56)
diff --git a/clang/lib/CodeGen/CGBuiltin.cpp b/clang/lib/CodeGen/CGBuiltin.cpp
index 9f95697f284c40..c7f63f71fbfcf7 100644
--- a/clang/lib/CodeGen/CGBuiltin.cpp
+++ b/clang/lib/CodeGen/CGBuiltin.cpp
@@ -18256,8 +18256,8 @@ Value *CodeGenFunction::EmitHLSLBuiltinExpr(unsigned BuiltinID,
     if (!E->getArg(0)->getType()->hasFloatingRepresentation())
       llvm_unreachable("lerp operand must have a float representation");
     return Builder.CreateIntrinsic(
-        /*ReturnType=*/X->getType(), Intrinsic::dx_lerp,
-        ArrayRef<Value *>{X, Y, S}, nullptr, "dx.lerp");
+        /*ReturnType=*/X->getType(), CGM.getHLSLRuntime().getLerpIntrinsic(),
+        ArrayRef<Value *>{X, Y, S}, nullptr, "hlsl.lerp");
   }
   case Builtin::BI__builtin_hlsl_elementwise_frac: {
     Value *Op0 = EmitScalarExpr(E->getArg(0));
diff --git a/clang/lib/CodeGen/CGHLSLRuntime.h b/clang/lib/CodeGen/CGHLSLRuntime.h
index 506b364f5b2ec7..0abe39dedcb96f 100644
--- a/clang/lib/CodeGen/CGHLSLRuntime.h
+++ b/clang/lib/CodeGen/CGHLSLRuntime.h
@@ -74,6 +74,7 @@ class CGHLSLRuntime {
 
   GENERATE_HLSL_INTRINSIC_FUNCTION(All, all)
   GENERATE_HLSL_INTRINSIC_FUNCTION(Any, any)
+  GENERATE_HLSL_INTRINSIC_FUNCTION(Lerp, lerp)
   GENERATE_HLSL_INTRINSIC_FUNCTION(ThreadId, thread_id)
 
   //===----------------------------------------------------------------------===//
diff --git a/clang/test/CodeGenHLSL/builtins/lerp.hlsl b/clang/test/CodeGenHLSL/builtins/lerp.hlsl
index 49cd04a10115ae..634b20be3a28d6 100644
--- a/clang/test/CodeGenHLSL/builtins/lerp.hlsl
+++ b/clang/test/CodeGenHLSL/builtins/lerp.hlsl
@@ -1,69 +1,92 @@
 // RUN: %clang_cc1 -finclude-default-header -x hlsl -triple \
 // RUN:   dxil-pc-shadermodel6.3-library %s -fnative-half-type \
 // RUN:   -emit-llvm -disable-llvm-passes -o - | FileCheck %s \ 
-// RUN:   --check-prefixes=CHECK,NATIVE_HALF
+// RUN:   --check-prefixes=CHECK,DXIL_CHECK,DXIL_NATIVE_HALF,NATIVE_HALF
 // RUN: %clang_cc1 -finclude-default-header -x hlsl -triple \
 // RUN:   dxil-pc-shadermodel6.3-library %s -emit-llvm -disable-llvm-passes \
-// RUN:   -o - | FileCheck %s --check-prefixes=CHECK,NO_HALF
+// RUN:   -o - | FileCheck %s --check-prefixes=CHECK,DXIL_CHECK,NO_HALF,DXIL_NO_HALF
+// RUN: %clang_cc1 -finclude-default-header -x hlsl -triple \
+// RUN:   spirv-unknown-vulkan-compute %s -fnative-half-type \
+// RUN:   -emit-llvm -disable-llvm-passes -o - | FileCheck %s \ 
+// RUN:   --check-prefixes=CHECK,NATIVE_HALF,SPIR_NATIVE_HALF,SPIR_CHECK
+// RUN: %clang_cc1 -finclude-default-header -x hlsl -triple \
+// RUN:   spirv-unknown-vulkan-compute %s -emit-llvm -disable-llvm-passes \
+// RUN:   -o - | FileCheck %s --check-prefixes=CHECK,NO_HALF,SPIR_NO_HALF,SPIR_CHECK
 
 
-// NATIVE_HALF: %dx.lerp = call half @llvm.dx.lerp.f16(half %0, half %1, half %2)
-// NATIVE_HALF: ret half %dx.lerp
-// NO_HALF: %dx.lerp = call float @llvm.dx.lerp.f32(float %0, float %1, float %2)
-// NO_HALF: ret float %dx.lerp
+// DXIL_NATIVE_HALF: %hlsl.lerp = call half @llvm.dx.lerp.f16(half %0, half %1, half %2)
+// SPIR_NATIVE_HALF: %hlsl.lerp = call half @llvm.spv.lerp.f16(half %0, half %1, half %2)
+// NATIVE_HALF: ret half %hlsl.lerp
+// DXIL_NO_HALF: %hlsl.lerp = call float @llvm.dx.lerp.f32(float %0, float %1, float %2)
+// SPIR_NO_HALF: %hlsl.lerp = call float @llvm.spv.lerp.f32(float %0, float %1, float %2)
+// NO_HALF: ret float %hlsl.lerp
 half test_lerp_half(half p0) { return lerp(p0, p0, p0); }
 
-// NATIVE_HALF: %dx.lerp = call <2 x half> @llvm.dx.lerp.v2f16(<2 x half> %0, <2 x half> %1, <2 x half> %2)
-// NATIVE_HALF: ret <2 x half> %dx.lerp
-// NO_HALF: %dx.lerp = call <2 x float> @llvm.dx.lerp.v2f32(<2 x float> %0, <2 x float> %1, <2 x float> %2)
-// NO_HALF: ret <2 x float> %dx.lerp
+// DXIL_NATIVE_HALF: %hlsl.lerp = call <2 x half> @llvm.dx.lerp.v2f16(<2 x half> %0, <2 x half> %1, <2 x half> %2)
+// SPIR_NATIVE_HALF: %hlsl.lerp = call <2 x half> @llvm.spv.lerp.v2f16(<2 x half> %0, <2 x half> %1, <2 x half> %2)
+// NATIVE_HALF: ret <2 x half> %hlsl.lerp
+// DXIL_NO_HALF: %hlsl.lerp = call <2 x float> @llvm.dx.lerp.v2f32(<2 x float> %0, <2 x float> %1, <2 x float> %2)
+// SPIR_NO_HALF: %hlsl.lerp = call <2 x float> @llvm.spv.lerp.v2f32(<2 x float> %0, <2 x float> %1, <2 x float> %2)
+// NO_HALF: ret <2 x float> %hlsl.lerp
 half2 test_lerp_half2(half2 p0) { return lerp(p0, p0, p0); }
 
-// NATIVE_HALF: %dx.lerp = call <3 x half> @llvm.dx.lerp.v3f16(<3 x half> %0, <3 x half> %1, <3 x half> %2)
-// NATIVE_HALF: ret <3 x half> %dx.lerp
-// NO_HALF: %dx.lerp = call <3 x float> @llvm.dx.lerp.v3f32(<3 x float> %0, <3 x float> %1, <3 x float> %2)
-// NO_HALF: ret <3 x float> %dx.lerp
+// DXIL_NATIVE_HALF: %hlsl.lerp = call <3 x half> @llvm.dx.lerp.v3f16(<3 x half> %0, <3 x half> %1, <3 x half> %2)
+// SPIR_NATIVE_HALF: %hlsl.lerp = call <3 x half> @llvm.spv.lerp.v3f16(<3 x half> %0, <3 x half> %1, <3 x half> %2)
+// NATIVE_HALF: ret <3 x half> %hlsl.lerp
+// DXIL_NO_HALF: %hlsl.lerp = call <3 x float> @llvm.dx.lerp.v3f32(<3 x float> %0, <3 x float> %1, <3 x float> %2)
+// SPIR_NO_HALF: %hlsl.lerp = call <3 x float> @llvm.spv.lerp.v3f32(<3 x float> %0, <3 x float> %1, <3 x float> %2)
+// NO_HALF: ret <3 x float> %hlsl.lerp
 half3 test_lerp_half3(half3 p0) { return lerp(p0, p0, p0); }
 
-// NATIVE_HALF: %dx.lerp = call <4 x half> @llvm.dx.lerp.v4f16(<4 x half> %0, <4 x half> %1, <4 x half> %2)
-// NATIVE_HALF: ret <4 x half> %dx.lerp
-// NO_HALF: %dx.lerp = call <4 x float> @llvm.dx.lerp.v4f32(<4 x float> %0, <4 x float> %1, <4 x float> %2)
-// NO_HALF: ret <4 x float> %dx.lerp
+// DXIL_NATIVE_HALF: %hlsl.lerp = call <4 x half> @llvm.dx.lerp.v4f16(<4 x half> %0, <4 x half> %1, <4 x half> %2)
+// SPIR_NATIVE_HALF: %hlsl.lerp = call <4 x half> @llvm.spv.lerp.v4f16(<4 x half> %0, <4 x half> %1, <4 x half> %2)
+// NATIVE_HALF: ret <4 x half> %hlsl.lerp
+// DXIL_NO_HALF: %hlsl.lerp = call <4 x float> @llvm.dx.lerp.v4f32(<4 x float> %0, <4 x float> %1, <4 x float> %2)
+// SPIR_NO_HALF: %hlsl.lerp = call <4 x float> @llvm.spv.lerp.v4f32(<4 x float> %0, <4 x float> %1, <4 x float> %2)
+// NO_HALF: ret <4 x float> %hlsl.lerp
 half4 test_lerp_half4(half4 p0) { return lerp(p0, p0, p0); }
 
-// CHECK: %dx.lerp = call float @llvm.dx.lerp.f32(float %0, float %1, float %2)
-// CHECK: ret float %dx.lerp
+// DXIL_CHECK: %hlsl.lerp = call float @llvm.dx.lerp.f32(float %0, float %1, float %2)
+// SPIR_CHECK: %hlsl.lerp = call float @llvm.spv.lerp.f32(float %0, float %1, float %2)
+// CHECK: ret float %hlsl.lerp
 float test_lerp_float(float p0) { return lerp(p0, p0, p0); }
 
-// CHECK: %dx.lerp = call <2 x float> @llvm.dx.lerp.v2f32(<2 x float> %0, <2 x float> %1, <2 x float> %2)
-// CHECK: ret <2 x float> %dx.lerp
+// DXIL_CHECK: %hlsl.lerp = call <2 x float> @llvm.dx.lerp.v2f32(<2 x float> %0, <2 x float> %1, <2 x float> %2)
+// SPIR_CHECK: %hlsl.lerp = call <2 x float> @llvm.spv.lerp.v2f32(<2 x float> %0, <2 x float> %1, <2 x float> %2)
+// CHECK: ret <2 x float> %hlsl.lerp
 float2 test_lerp_float2(float2 p0) { return lerp(p0, p0, p0); }
 
-// CHECK: %dx.lerp = call <3 x float> @llvm.dx.lerp.v3f32(<3 x float> %0, <3 x float> %1, <3 x float> %2)
-// CHECK: ret <3 x float> %dx.lerp
+// DXIL_CHECK: %hlsl.lerp = call <3 x float> @llvm.dx.lerp.v3f32(<3 x float> %0, <3 x float> %1, <3 x float> %2)
+// SPIR_CHECK: %hlsl.lerp = call <3 x float> @llvm.spv.lerp.v3f32(<3 x float> %0, <3 x float> %1, <3 x float> %2)
+// CHECK: ret <3 x float> %hlsl.lerp
 float3 test_lerp_float3(float3 p0) { return lerp(p0, p0, p0); }
 
-// CHECK: %dx.lerp = call <4 x float> @llvm.dx.lerp.v4f32(<4 x float> %0, <4 x float> %1, <4 x float> %2)
-// CHECK: ret <4 x float> %dx.lerp
+// DXIL_CHECK: %hlsl.lerp = call <4 x float> @llvm.dx.lerp.v4f32(<4 x float> %0, <4 x float> %1, <4 x float> %2)
+// SPIR_CHECK: %hlsl.lerp = call <4 x float> @llvm.spv.lerp.v4f32(<4 x float> %0, <4 x float> %1, <4 x float> %2)
+// CHECK: ret <4 x float> %hlsl.lerp
 float4 test_lerp_float4(float4 p0) { return lerp(p0, p0, p0); }
 
-// CHECK: %dx.lerp = call <2 x float> @llvm.dx.lerp.v2f32(<2 x float> %splat.splat, <2 x float> %1, <2 x float> %2)
-// CHECK: ret <2 x float> %dx.lerp
+// DXIL_CHECK: %hlsl.lerp = call <2 x float> @llvm.dx.lerp.v2f32(<2 x float> %splat.splat, <2 x float> %1, <2 x float> %2)
+// SPIR_CHECK: %hlsl.lerp = call <2 x float> @llvm.spv.lerp.v2f32(<2 x float> %splat.splat, <2 x float> %1, <2 x float> %2)
+// CHECK: ret <2 x float> %hlsl.lerp
 float2 test_lerp_float2_splat(float p0, float2 p1) { return lerp(p0, p1, p1); }
 
-// CHECK: %dx.lerp = call <3 x float> @llvm.dx.lerp.v3f32(<3 x float> %splat.splat, <3 x float> %1, <3 x float> %2)
-// CHECK: ret <3 x float> %dx.lerp
+// DXIL_CHECK: %hlsl.lerp = call <3 x float> @llvm.dx.lerp.v3f32(<3 x float> %splat.splat, <3 x float> %1, <3 x float> %2)
+// SPIR_CHECK: %hlsl.lerp = call <3 x float> @llvm.spv.lerp.v3f32(<3 x float> %splat.splat, <3 x float> %1, <3 x float> %2)
+// CHECK: ret <3 x float> %hlsl.lerp
 float3 test_lerp_float3_splat(float p0, float3 p1) { return lerp(p0, p1, p1); }
 
-// CHECK:  %dx.lerp = call <4 x float> @llvm.dx.lerp.v4f32(<4 x float> %splat.splat, <4 x float> %1, <4 x float> %2)
-// CHECK:  ret <4 x float> %dx.lerp
+// DXIL_CHECK:  %hlsl.lerp = call <4 x float> @llvm.dx.lerp.v4f32(<4 x float> %splat.splat, <4 x float> %1, <4 x float> %2)
+// SPIR_CHECK:  %hlsl.lerp = call <4 x float> @llvm.spv.lerp.v4f32(<4 x float> %splat.splat, <4 x float> %1, <4 x float> %2)
+// CHECK:  ret <4 x float> %hlsl.lerp
 float4 test_lerp_float4_splat(float p0, float4 p1) { return lerp(p0, p1, p1); }
 
 // CHECK: %conv = sitofp i32 %2 to float
 // CHECK: %splat.splatinsert = insertelement <2 x float> poison, float %conv, i64 0
 // CHECK: %splat.splat = shufflevector <2 x float> %splat.splatinsert, <2 x float> poison, <2 x i32> zeroinitializer
-// CHECK: %dx.lerp = call <2 x float> @llvm.dx.lerp.v2f32(<2 x float> %0, <2 x float> %1, <2 x float> %splat.splat)
-// CHECK: ret <2 x float> %dx.lerp
+// DXIL_CHECK: %hlsl.lerp = call <2 x float> @llvm.dx.lerp.v2f32(<2 x float> %0, <2 x float> %1, <2 x float> %splat.splat)
+// SPIR_CHECK: %hlsl.lerp = call <2 x float> @llvm.spv.lerp.v2f32(<2 x float> %0, <2 x float> %1, <2 x float> %splat.splat)
+// CHECK: ret <2 x float> %hlsl.lerp
 float2 test_lerp_float2_int_splat(float2 p0, int p1) {
   return lerp(p0, p0, p1);
 }
@@ -71,8 +94,9 @@ float2 test_lerp_float2_int_splat(float2 p0, int p1) {
 // CHECK: %conv = sitofp i32 %2 to float
 // CHECK: %splat.splatinsert = insertelement <3 x float> poison, float %conv, i64 0
 // CHECK: %splat.splat = shufflevector <3 x float> %splat.splatinsert, <3 x float> poison, <3 x i32> zeroinitializer
-// CHECK:  %dx.lerp = call <3 x float> @llvm.dx.lerp.v3f32(<3 x float> %0, <3 x float> %1, <3 x float> %splat.splat)
-// CHECK: ret <3 x float> %dx.lerp
+// DXIL_CHECK:  %hlsl.lerp = call <3 x float> @llvm.dx.lerp.v3f32(<3 x float> %0, <3 x float> %1, <3 x float> %splat.splat)
+// SPIR_CHECK:  %hlsl.lerp = call <3 x float> @llvm.spv.lerp.v3f32(<3 x float> %0, <3 x float> %1, <3 x float> %splat.splat)
+// CHECK: ret <3 x float> %hlsl.lerp
 float3 test_lerp_float3_int_splat(float3 p0, int p1) {
   return lerp(p0, p0, p1);
 }
diff --git a/llvm/include/llvm/IR/IntrinsicsSPIRV.td b/llvm/include/llvm/IR/IntrinsicsSPIRV.td
index b6618baceb5608..8660782d71d950 100644
--- a/llvm/include/llvm/IR/IntrinsicsSPIRV.td
+++ b/llvm/include/llvm/IR/IntrinsicsSPIRV.td
@@ -58,4 +58,6 @@ let TargetPrefix = "spv" in {
       Intrinsic<[ llvm_ptr_ty ], [llvm_i8_ty], [IntrWillReturn]>;
   def int_spv_all : DefaultAttrsIntrinsic<[llvm_i1_ty], [llvm_any_ty]>;
   def int_spv_any : DefaultAttrsIntrinsic<[llvm_i1_ty], [llvm_any_ty]>;
+  def int_spv_lerp : Intrinsic<[LLVMMatchType<0>], [llvm_anyfloat_ty, LLVMMatchType<0>,LLVMMatchType<0>], 
+    [IntrNoMem, IntrWillReturn] >;
 }
diff --git a/llvm/lib/Target/SPIRV/SPIRVInstructionSelector.cpp b/llvm/lib/Target/SPIRV/SPIRVInstructionSelector.cpp
index 200fe38298c021..92872a035556f9 100644
--- a/llvm/lib/Target/SPIRV/SPIRVInstructionSelector.cpp
+++ b/llvm/lib/Target/SPIRV/SPIRVInstructionSelector.cpp
@@ -170,6 +170,9 @@ class SPIRVInstructionSelector : public InstructionSelector {
   bool selectFCmp(Register ResVReg, const SPIRVType *ResType,
                   MachineInstr &I) const;
 
+  bool selectFmix(Register ResVReg, const SPIRVType *ResType,
+                  MachineInstr &I) const;
+
   void renderImm32(MachineInstrBuilder &MIB, const MachineInstr &I,
                    int OpIdx) const;
   void renderFImm32(MachineInstrBuilder &MIB, const MachineInstr &I,
@@ -1238,6 +1241,27 @@ bool SPIRVInstructionSelector::selectAny(Register ResVReg,
   return selectAnyOrAll(ResVReg, ResType, I, SPIRV::OpAny);
 }
 
+bool SPIRVInstructionSelector::selectFmix(Register ResVReg,
+                                          const SPIRVType *ResType,
+                                          MachineInstr &I) const {
+
+  assert(I.getNumOperands() == 5);
+  assert(I.getOperand(2).isReg());
+  assert(I.getOperand(3).isReg());
+  assert(I.getOperand(4).isReg());
+  MachineBasicBlock &BB = *I.getParent();
+
+  return BuildMI(BB, I, I.getDebugLoc(), TII.get(SPIRV::OpExtInst))
+      .addDef(ResVReg)
+      .addUse(GR.getSPIRVTypeID(ResType))
+      .addImm(static_cast<uint32_t>(SPIRV::InstructionSet::GLSL_std_450))
+      .addImm(GL::FMix)
+      .addUse(I.getOperand(2).getReg())
+      .addUse(I.getOperand(3).getReg())
+      .addUse(I.getOperand(4).getReg())
+      .constrainAllUses(TII, TRI, RBI);
+}
+
 bool SPIRVInstructionSelector::selectBitreverse(Register ResVReg,
                                                 const SPIRVType *ResType,
                                                 MachineInstr &I) const {
@@ -1898,6 +1922,8 @@ bool SPIRVInstructionSelector::selectIntrinsic(Register ResVReg,
     return selectAll(ResVReg, ResType, I);
   case Intrinsic::spv_any:
     return selectAny(ResVReg, ResType, I);
+  case Intrinsic::spv_lerp:
+    return selectFmix(ResVReg, ResType, I);
   case Intrinsic::spv_lifetime_start:
   case Intrinsic::spv_lifetime_end: {
     unsigned Op = IID == Intrinsic::spv_lifetime_start ? SPIRV::OpLifetimeStart
diff --git a/llvm/test/CodeGen/SPIRV/hlsl-intrinsics/lerp.ll b/llvm/test/CodeGen/SPIRV/hlsl-intrinsics/lerp.ll
new file mode 100644
index 00000000000000..57171ae136f4ee
--- /dev/null
+++ b/llvm/test/CodeGen/SPIRV/hlsl-intrinsics/lerp.ll
@@ -0,0 +1,56 @@
+; RUN: llc -O0 -mtriple=spirv-unknown-unknown %s -o - | FileCheck %s
+; RUN: %if spirv-tools %{ llc -O0 -mtriple=spirv-unknown-unknown %s -o - -filetype=obj | spirv-val %}
+
+; Make sure SPIRV operation function calls for lerp are generated as FMix
+
+; CHECK-DAG: %[[#op_ext_glsl:]] = OpExtInstImport "GLSL.std.450"
+; CHECK-DAG: %[[#float_32:]] = OpTypeFloat 32
+; CHECK-DAG: %[[#float_16:]] = OpTypeFloat 16
+; CHECK-DAG: %[[#vec4_float_16:]] = OpTypeVector %[[#float_16]] 4
+; CHECK-DAG: %[[#vec4_float_32:]] = OpTypeVector %[[#float_32]] 4
+
+define noundef half @lerp_half(half noundef %a, half noundef %b, half noundef %c) {
+entry:
+  ; CHECK: %[[#arg0:]] = OpFunctionParameter %[[#]]
+  ; CHECK: %[[#arg1:]] = OpFunctionParameter %[[#]]
+  ; CHECK: %[[#arg2:]] = OpFunctionParameter %[[#]]
+  ; CHECK: %[[#]] = OpExtInst %[[#float_16:]] %[[#op_ext_glsl:]] FMix %[[#arg0:]] %[[#arg1:]] %[[#arg2:]]
+  %hlsl.lerp = call half @llvm.spv.lerp.f16(half %a, half %b, half %c)
+  ret half %hlsl.lerp
+}
+
+
+define noundef float @lerp_float(float noundef %a, float noundef %b, float noundef %c) {
+entry:
+  ; CHECK: %[[#arg0:]] = OpFunctionParameter %[[#]]
+  ; CHECK: %[[#arg1:]] = OpFunctionParameter %[[#]]
+  ; CHECK: %[[#arg2:]] = OpFunctionParameter %[[#]]
+  ; CHECK: %[[#]] = OpExtInst %[[#float_32:]] %[[#op_ext_glsl:]] FMix %[[#arg0:]] %[[#arg1:]] %[[#arg2:]]
+  %hlsl.lerp = call float @llvm.spv.lerp.f32(float %a, float %b, float %c)
+  ret float %hlsl.lerp
+}
+
+define noundef <4 x half> @lerp_half4(<4 x half> noundef %a, <4 x half> noundef %b, <4 x half> noundef %c) {
+entry:
+  ; CHECK: %[[#arg0:]] = OpFunctionParameter %[[#]]
+  ; CHECK: %[[#arg1:]] = OpFunctionParameter %[[#]]
+  ; CHECK: %[[#arg2:]] = OpFunctionParameter %[[#]]
+  ; CHECK: %[[#]] = OpExtInst %[[#vec4_float_16:]] %[[#op_ext_glsl:]] FMix %[[#arg0:]] %[[#arg1:]] %[[#arg2:]]
+  %hlsl.lerp = call <4 x half> @llvm.spv.lerp.v4f16(<4 x half> %a, <4 x half> %b, <4 x half> %c)
+  ret <4 x half> %hlsl.lerp
+}
+
+define noundef <4 x float> @lerp_float4(<4 x float> noundef %a, <4 x float> noundef %b, <4 x float> noundef %c) {
+entry:
+  ; CHECK: %[[#arg0:]] = OpFunctionParameter %[[#]]
+  ; CHECK: %[[#arg1:]] = OpFunctionParameter %[[#]]
+  ; CHECK: %[[#arg2:]] = OpFunctionParameter %[[#]]
+  ; CHECK: %[[#]] = OpExtInst %[[#vec4_float_32:]] %[[#op_ext_glsl:]] FMix %[[#arg0:]] %[[#arg1:]] %[[#arg2:]]
+  %hlsl.lerp = call <4 x float> @llvm.spv.lerp.v4f32(<4 x float> %a, <4 x float> %b, <4 x float> %c)
+  ret <4 x float> %hlsl.lerp
+}
+
+declare half @llvm.spv.lerp.f16(half, half, half)
+declare float @llvm.spv.lerp.f32(float, float, float)
+declare <4 x half> @llvm.spv.lerp.v4f16(<4 x half>, <4 x half>, <4 x half>)
+declare <4 x float> @llvm.spv.lerp.v4f32(<4 x float>, <4 x float>, <4 x float>)

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llvmbot commented Apr 16, 2024

@llvm/pr-subscribers-clang-codegen

Author: Farzon Lotfi (farzonl)

Changes
  • clang/lib/CodeGen/CGBuiltin.cpp - switch to using getLerpIntrinsic() to abstract backend intrinsic
  • clang/lib/CodeGen/CGHLSLRuntime.h - add getLerpIntrinsic()
  • llvm/include/llvm/IR/IntrinsicsSPIRV.td - add SPIRV intrinsic for lerp
  • llvm/lib/Target/SPIRV/SPIRVInstructionSelector.cpp - add mapping of HLSL's lerp to GLSL's Fmix.

resolves #88940

Full diff: https://github.com/llvm/llvm-project/pull/88976.diff

6 Files Affected:

  • (modified) clang/lib/CodeGen/CGBuiltin.cpp (+2-2)
  • (modified) clang/lib/CodeGen/CGHLSLRuntime.h (+1)
  • (modified) clang/test/CodeGenHLSL/builtins/lerp.hlsl (+60-36)
  • (modified) llvm/include/llvm/IR/IntrinsicsSPIRV.td (+2)
  • (modified) llvm/lib/Target/SPIRV/SPIRVInstructionSelector.cpp (+26)
  • (added) llvm/test/CodeGen/SPIRV/hlsl-intrinsics/lerp.ll (+56)
diff --git a/clang/lib/CodeGen/CGBuiltin.cpp b/clang/lib/CodeGen/CGBuiltin.cpp
index 9f95697f284c40..c7f63f71fbfcf7 100644
--- a/clang/lib/CodeGen/CGBuiltin.cpp
+++ b/clang/lib/CodeGen/CGBuiltin.cpp
@@ -18256,8 +18256,8 @@ Value *CodeGenFunction::EmitHLSLBuiltinExpr(unsigned BuiltinID,
     if (!E->getArg(0)->getType()->hasFloatingRepresentation())
       llvm_unreachable("lerp operand must have a float representation");
     return Builder.CreateIntrinsic(
-        /*ReturnType=*/X->getType(), Intrinsic::dx_lerp,
-        ArrayRef<Value *>{X, Y, S}, nullptr, "dx.lerp");
+        /*ReturnType=*/X->getType(), CGM.getHLSLRuntime().getLerpIntrinsic(),
+        ArrayRef<Value *>{X, Y, S}, nullptr, "hlsl.lerp");
   }
   case Builtin::BI__builtin_hlsl_elementwise_frac: {
     Value *Op0 = EmitScalarExpr(E->getArg(0));
diff --git a/clang/lib/CodeGen/CGHLSLRuntime.h b/clang/lib/CodeGen/CGHLSLRuntime.h
index 506b364f5b2ec7..0abe39dedcb96f 100644
--- a/clang/lib/CodeGen/CGHLSLRuntime.h
+++ b/clang/lib/CodeGen/CGHLSLRuntime.h
@@ -74,6 +74,7 @@ class CGHLSLRuntime {
 
   GENERATE_HLSL_INTRINSIC_FUNCTION(All, all)
   GENERATE_HLSL_INTRINSIC_FUNCTION(Any, any)
+  GENERATE_HLSL_INTRINSIC_FUNCTION(Lerp, lerp)
   GENERATE_HLSL_INTRINSIC_FUNCTION(ThreadId, thread_id)
 
   //===----------------------------------------------------------------------===//
diff --git a/clang/test/CodeGenHLSL/builtins/lerp.hlsl b/clang/test/CodeGenHLSL/builtins/lerp.hlsl
index 49cd04a10115ae..634b20be3a28d6 100644
--- a/clang/test/CodeGenHLSL/builtins/lerp.hlsl
+++ b/clang/test/CodeGenHLSL/builtins/lerp.hlsl
@@ -1,69 +1,92 @@
 // RUN: %clang_cc1 -finclude-default-header -x hlsl -triple \
 // RUN:   dxil-pc-shadermodel6.3-library %s -fnative-half-type \
 // RUN:   -emit-llvm -disable-llvm-passes -o - | FileCheck %s \ 
-// RUN:   --check-prefixes=CHECK,NATIVE_HALF
+// RUN:   --check-prefixes=CHECK,DXIL_CHECK,DXIL_NATIVE_HALF,NATIVE_HALF
 // RUN: %clang_cc1 -finclude-default-header -x hlsl -triple \
 // RUN:   dxil-pc-shadermodel6.3-library %s -emit-llvm -disable-llvm-passes \
-// RUN:   -o - | FileCheck %s --check-prefixes=CHECK,NO_HALF
+// RUN:   -o - | FileCheck %s --check-prefixes=CHECK,DXIL_CHECK,NO_HALF,DXIL_NO_HALF
+// RUN: %clang_cc1 -finclude-default-header -x hlsl -triple \
+// RUN:   spirv-unknown-vulkan-compute %s -fnative-half-type \
+// RUN:   -emit-llvm -disable-llvm-passes -o - | FileCheck %s \ 
+// RUN:   --check-prefixes=CHECK,NATIVE_HALF,SPIR_NATIVE_HALF,SPIR_CHECK
+// RUN: %clang_cc1 -finclude-default-header -x hlsl -triple \
+// RUN:   spirv-unknown-vulkan-compute %s -emit-llvm -disable-llvm-passes \
+// RUN:   -o - | FileCheck %s --check-prefixes=CHECK,NO_HALF,SPIR_NO_HALF,SPIR_CHECK
 
 
-// NATIVE_HALF: %dx.lerp = call half @llvm.dx.lerp.f16(half %0, half %1, half %2)
-// NATIVE_HALF: ret half %dx.lerp
-// NO_HALF: %dx.lerp = call float @llvm.dx.lerp.f32(float %0, float %1, float %2)
-// NO_HALF: ret float %dx.lerp
+// DXIL_NATIVE_HALF: %hlsl.lerp = call half @llvm.dx.lerp.f16(half %0, half %1, half %2)
+// SPIR_NATIVE_HALF: %hlsl.lerp = call half @llvm.spv.lerp.f16(half %0, half %1, half %2)
+// NATIVE_HALF: ret half %hlsl.lerp
+// DXIL_NO_HALF: %hlsl.lerp = call float @llvm.dx.lerp.f32(float %0, float %1, float %2)
+// SPIR_NO_HALF: %hlsl.lerp = call float @llvm.spv.lerp.f32(float %0, float %1, float %2)
+// NO_HALF: ret float %hlsl.lerp
 half test_lerp_half(half p0) { return lerp(p0, p0, p0); }
 
-// NATIVE_HALF: %dx.lerp = call <2 x half> @llvm.dx.lerp.v2f16(<2 x half> %0, <2 x half> %1, <2 x half> %2)
-// NATIVE_HALF: ret <2 x half> %dx.lerp
-// NO_HALF: %dx.lerp = call <2 x float> @llvm.dx.lerp.v2f32(<2 x float> %0, <2 x float> %1, <2 x float> %2)
-// NO_HALF: ret <2 x float> %dx.lerp
+// DXIL_NATIVE_HALF: %hlsl.lerp = call <2 x half> @llvm.dx.lerp.v2f16(<2 x half> %0, <2 x half> %1, <2 x half> %2)
+// SPIR_NATIVE_HALF: %hlsl.lerp = call <2 x half> @llvm.spv.lerp.v2f16(<2 x half> %0, <2 x half> %1, <2 x half> %2)
+// NATIVE_HALF: ret <2 x half> %hlsl.lerp
+// DXIL_NO_HALF: %hlsl.lerp = call <2 x float> @llvm.dx.lerp.v2f32(<2 x float> %0, <2 x float> %1, <2 x float> %2)
+// SPIR_NO_HALF: %hlsl.lerp = call <2 x float> @llvm.spv.lerp.v2f32(<2 x float> %0, <2 x float> %1, <2 x float> %2)
+// NO_HALF: ret <2 x float> %hlsl.lerp
 half2 test_lerp_half2(half2 p0) { return lerp(p0, p0, p0); }
 
-// NATIVE_HALF: %dx.lerp = call <3 x half> @llvm.dx.lerp.v3f16(<3 x half> %0, <3 x half> %1, <3 x half> %2)
-// NATIVE_HALF: ret <3 x half> %dx.lerp
-// NO_HALF: %dx.lerp = call <3 x float> @llvm.dx.lerp.v3f32(<3 x float> %0, <3 x float> %1, <3 x float> %2)
-// NO_HALF: ret <3 x float> %dx.lerp
+// DXIL_NATIVE_HALF: %hlsl.lerp = call <3 x half> @llvm.dx.lerp.v3f16(<3 x half> %0, <3 x half> %1, <3 x half> %2)
+// SPIR_NATIVE_HALF: %hlsl.lerp = call <3 x half> @llvm.spv.lerp.v3f16(<3 x half> %0, <3 x half> %1, <3 x half> %2)
+// NATIVE_HALF: ret <3 x half> %hlsl.lerp
+// DXIL_NO_HALF: %hlsl.lerp = call <3 x float> @llvm.dx.lerp.v3f32(<3 x float> %0, <3 x float> %1, <3 x float> %2)
+// SPIR_NO_HALF: %hlsl.lerp = call <3 x float> @llvm.spv.lerp.v3f32(<3 x float> %0, <3 x float> %1, <3 x float> %2)
+// NO_HALF: ret <3 x float> %hlsl.lerp
 half3 test_lerp_half3(half3 p0) { return lerp(p0, p0, p0); }
 
-// NATIVE_HALF: %dx.lerp = call <4 x half> @llvm.dx.lerp.v4f16(<4 x half> %0, <4 x half> %1, <4 x half> %2)
-// NATIVE_HALF: ret <4 x half> %dx.lerp
-// NO_HALF: %dx.lerp = call <4 x float> @llvm.dx.lerp.v4f32(<4 x float> %0, <4 x float> %1, <4 x float> %2)
-// NO_HALF: ret <4 x float> %dx.lerp
+// DXIL_NATIVE_HALF: %hlsl.lerp = call <4 x half> @llvm.dx.lerp.v4f16(<4 x half> %0, <4 x half> %1, <4 x half> %2)
+// SPIR_NATIVE_HALF: %hlsl.lerp = call <4 x half> @llvm.spv.lerp.v4f16(<4 x half> %0, <4 x half> %1, <4 x half> %2)
+// NATIVE_HALF: ret <4 x half> %hlsl.lerp
+// DXIL_NO_HALF: %hlsl.lerp = call <4 x float> @llvm.dx.lerp.v4f32(<4 x float> %0, <4 x float> %1, <4 x float> %2)
+// SPIR_NO_HALF: %hlsl.lerp = call <4 x float> @llvm.spv.lerp.v4f32(<4 x float> %0, <4 x float> %1, <4 x float> %2)
+// NO_HALF: ret <4 x float> %hlsl.lerp
 half4 test_lerp_half4(half4 p0) { return lerp(p0, p0, p0); }
 
-// CHECK: %dx.lerp = call float @llvm.dx.lerp.f32(float %0, float %1, float %2)
-// CHECK: ret float %dx.lerp
+// DXIL_CHECK: %hlsl.lerp = call float @llvm.dx.lerp.f32(float %0, float %1, float %2)
+// SPIR_CHECK: %hlsl.lerp = call float @llvm.spv.lerp.f32(float %0, float %1, float %2)
+// CHECK: ret float %hlsl.lerp
 float test_lerp_float(float p0) { return lerp(p0, p0, p0); }
 
-// CHECK: %dx.lerp = call <2 x float> @llvm.dx.lerp.v2f32(<2 x float> %0, <2 x float> %1, <2 x float> %2)
-// CHECK: ret <2 x float> %dx.lerp
+// DXIL_CHECK: %hlsl.lerp = call <2 x float> @llvm.dx.lerp.v2f32(<2 x float> %0, <2 x float> %1, <2 x float> %2)
+// SPIR_CHECK: %hlsl.lerp = call <2 x float> @llvm.spv.lerp.v2f32(<2 x float> %0, <2 x float> %1, <2 x float> %2)
+// CHECK: ret <2 x float> %hlsl.lerp
 float2 test_lerp_float2(float2 p0) { return lerp(p0, p0, p0); }
 
-// CHECK: %dx.lerp = call <3 x float> @llvm.dx.lerp.v3f32(<3 x float> %0, <3 x float> %1, <3 x float> %2)
-// CHECK: ret <3 x float> %dx.lerp
+// DXIL_CHECK: %hlsl.lerp = call <3 x float> @llvm.dx.lerp.v3f32(<3 x float> %0, <3 x float> %1, <3 x float> %2)
+// SPIR_CHECK: %hlsl.lerp = call <3 x float> @llvm.spv.lerp.v3f32(<3 x float> %0, <3 x float> %1, <3 x float> %2)
+// CHECK: ret <3 x float> %hlsl.lerp
 float3 test_lerp_float3(float3 p0) { return lerp(p0, p0, p0); }
 
-// CHECK: %dx.lerp = call <4 x float> @llvm.dx.lerp.v4f32(<4 x float> %0, <4 x float> %1, <4 x float> %2)
-// CHECK: ret <4 x float> %dx.lerp
+// DXIL_CHECK: %hlsl.lerp = call <4 x float> @llvm.dx.lerp.v4f32(<4 x float> %0, <4 x float> %1, <4 x float> %2)
+// SPIR_CHECK: %hlsl.lerp = call <4 x float> @llvm.spv.lerp.v4f32(<4 x float> %0, <4 x float> %1, <4 x float> %2)
+// CHECK: ret <4 x float> %hlsl.lerp
 float4 test_lerp_float4(float4 p0) { return lerp(p0, p0, p0); }
 
-// CHECK: %dx.lerp = call <2 x float> @llvm.dx.lerp.v2f32(<2 x float> %splat.splat, <2 x float> %1, <2 x float> %2)
-// CHECK: ret <2 x float> %dx.lerp
+// DXIL_CHECK: %hlsl.lerp = call <2 x float> @llvm.dx.lerp.v2f32(<2 x float> %splat.splat, <2 x float> %1, <2 x float> %2)
+// SPIR_CHECK: %hlsl.lerp = call <2 x float> @llvm.spv.lerp.v2f32(<2 x float> %splat.splat, <2 x float> %1, <2 x float> %2)
+// CHECK: ret <2 x float> %hlsl.lerp
 float2 test_lerp_float2_splat(float p0, float2 p1) { return lerp(p0, p1, p1); }
 
-// CHECK: %dx.lerp = call <3 x float> @llvm.dx.lerp.v3f32(<3 x float> %splat.splat, <3 x float> %1, <3 x float> %2)
-// CHECK: ret <3 x float> %dx.lerp
+// DXIL_CHECK: %hlsl.lerp = call <3 x float> @llvm.dx.lerp.v3f32(<3 x float> %splat.splat, <3 x float> %1, <3 x float> %2)
+// SPIR_CHECK: %hlsl.lerp = call <3 x float> @llvm.spv.lerp.v3f32(<3 x float> %splat.splat, <3 x float> %1, <3 x float> %2)
+// CHECK: ret <3 x float> %hlsl.lerp
 float3 test_lerp_float3_splat(float p0, float3 p1) { return lerp(p0, p1, p1); }
 
-// CHECK:  %dx.lerp = call <4 x float> @llvm.dx.lerp.v4f32(<4 x float> %splat.splat, <4 x float> %1, <4 x float> %2)
-// CHECK:  ret <4 x float> %dx.lerp
+// DXIL_CHECK:  %hlsl.lerp = call <4 x float> @llvm.dx.lerp.v4f32(<4 x float> %splat.splat, <4 x float> %1, <4 x float> %2)
+// SPIR_CHECK:  %hlsl.lerp = call <4 x float> @llvm.spv.lerp.v4f32(<4 x float> %splat.splat, <4 x float> %1, <4 x float> %2)
+// CHECK:  ret <4 x float> %hlsl.lerp
 float4 test_lerp_float4_splat(float p0, float4 p1) { return lerp(p0, p1, p1); }
 
 // CHECK: %conv = sitofp i32 %2 to float
 // CHECK: %splat.splatinsert = insertelement <2 x float> poison, float %conv, i64 0
 // CHECK: %splat.splat = shufflevector <2 x float> %splat.splatinsert, <2 x float> poison, <2 x i32> zeroinitializer
-// CHECK: %dx.lerp = call <2 x float> @llvm.dx.lerp.v2f32(<2 x float> %0, <2 x float> %1, <2 x float> %splat.splat)
-// CHECK: ret <2 x float> %dx.lerp
+// DXIL_CHECK: %hlsl.lerp = call <2 x float> @llvm.dx.lerp.v2f32(<2 x float> %0, <2 x float> %1, <2 x float> %splat.splat)
+// SPIR_CHECK: %hlsl.lerp = call <2 x float> @llvm.spv.lerp.v2f32(<2 x float> %0, <2 x float> %1, <2 x float> %splat.splat)
+// CHECK: ret <2 x float> %hlsl.lerp
 float2 test_lerp_float2_int_splat(float2 p0, int p1) {
   return lerp(p0, p0, p1);
 }
@@ -71,8 +94,9 @@ float2 test_lerp_float2_int_splat(float2 p0, int p1) {
 // CHECK: %conv = sitofp i32 %2 to float
 // CHECK: %splat.splatinsert = insertelement <3 x float> poison, float %conv, i64 0
 // CHECK: %splat.splat = shufflevector <3 x float> %splat.splatinsert, <3 x float> poison, <3 x i32> zeroinitializer
-// CHECK:  %dx.lerp = call <3 x float> @llvm.dx.lerp.v3f32(<3 x float> %0, <3 x float> %1, <3 x float> %splat.splat)
-// CHECK: ret <3 x float> %dx.lerp
+// DXIL_CHECK:  %hlsl.lerp = call <3 x float> @llvm.dx.lerp.v3f32(<3 x float> %0, <3 x float> %1, <3 x float> %splat.splat)
+// SPIR_CHECK:  %hlsl.lerp = call <3 x float> @llvm.spv.lerp.v3f32(<3 x float> %0, <3 x float> %1, <3 x float> %splat.splat)
+// CHECK: ret <3 x float> %hlsl.lerp
 float3 test_lerp_float3_int_splat(float3 p0, int p1) {
   return lerp(p0, p0, p1);
 }
diff --git a/llvm/include/llvm/IR/IntrinsicsSPIRV.td b/llvm/include/llvm/IR/IntrinsicsSPIRV.td
index b6618baceb5608..8660782d71d950 100644
--- a/llvm/include/llvm/IR/IntrinsicsSPIRV.td
+++ b/llvm/include/llvm/IR/IntrinsicsSPIRV.td
@@ -58,4 +58,6 @@ let TargetPrefix = "spv" in {
       Intrinsic<[ llvm_ptr_ty ], [llvm_i8_ty], [IntrWillReturn]>;
   def int_spv_all : DefaultAttrsIntrinsic<[llvm_i1_ty], [llvm_any_ty]>;
   def int_spv_any : DefaultAttrsIntrinsic<[llvm_i1_ty], [llvm_any_ty]>;
+  def int_spv_lerp : Intrinsic<[LLVMMatchType<0>], [llvm_anyfloat_ty, LLVMMatchType<0>,LLVMMatchType<0>], 
+    [IntrNoMem, IntrWillReturn] >;
 }
diff --git a/llvm/lib/Target/SPIRV/SPIRVInstructionSelector.cpp b/llvm/lib/Target/SPIRV/SPIRVInstructionSelector.cpp
index 200fe38298c021..92872a035556f9 100644
--- a/llvm/lib/Target/SPIRV/SPIRVInstructionSelector.cpp
+++ b/llvm/lib/Target/SPIRV/SPIRVInstructionSelector.cpp
@@ -170,6 +170,9 @@ class SPIRVInstructionSelector : public InstructionSelector {
   bool selectFCmp(Register ResVReg, const SPIRVType *ResType,
                   MachineInstr &I) const;
 
+  bool selectFmix(Register ResVReg, const SPIRVType *ResType,
+                  MachineInstr &I) const;
+
   void renderImm32(MachineInstrBuilder &MIB, const MachineInstr &I,
                    int OpIdx) const;
   void renderFImm32(MachineInstrBuilder &MIB, const MachineInstr &I,
@@ -1238,6 +1241,27 @@ bool SPIRVInstructionSelector::selectAny(Register ResVReg,
   return selectAnyOrAll(ResVReg, ResType, I, SPIRV::OpAny);
 }
 
+bool SPIRVInstructionSelector::selectFmix(Register ResVReg,
+                                          const SPIRVType *ResType,
+                                          MachineInstr &I) const {
+
+  assert(I.getNumOperands() == 5);
+  assert(I.getOperand(2).isReg());
+  assert(I.getOperand(3).isReg());
+  assert(I.getOperand(4).isReg());
+  MachineBasicBlock &BB = *I.getParent();
+
+  return BuildMI(BB, I, I.getDebugLoc(), TII.get(SPIRV::OpExtInst))
+      .addDef(ResVReg)
+      .addUse(GR.getSPIRVTypeID(ResType))
+      .addImm(static_cast<uint32_t>(SPIRV::InstructionSet::GLSL_std_450))
+      .addImm(GL::FMix)
+      .addUse(I.getOperand(2).getReg())
+      .addUse(I.getOperand(3).getReg())
+      .addUse(I.getOperand(4).getReg())
+      .constrainAllUses(TII, TRI, RBI);
+}
+
 bool SPIRVInstructionSelector::selectBitreverse(Register ResVReg,
                                                 const SPIRVType *ResType,
                                                 MachineInstr &I) const {
@@ -1898,6 +1922,8 @@ bool SPIRVInstructionSelector::selectIntrinsic(Register ResVReg,
     return selectAll(ResVReg, ResType, I);
   case Intrinsic::spv_any:
     return selectAny(ResVReg, ResType, I);
+  case Intrinsic::spv_lerp:
+    return selectFmix(ResVReg, ResType, I);
   case Intrinsic::spv_lifetime_start:
   case Intrinsic::spv_lifetime_end: {
     unsigned Op = IID == Intrinsic::spv_lifetime_start ? SPIRV::OpLifetimeStart
diff --git a/llvm/test/CodeGen/SPIRV/hlsl-intrinsics/lerp.ll b/llvm/test/CodeGen/SPIRV/hlsl-intrinsics/lerp.ll
new file mode 100644
index 00000000000000..57171ae136f4ee
--- /dev/null
+++ b/llvm/test/CodeGen/SPIRV/hlsl-intrinsics/lerp.ll
@@ -0,0 +1,56 @@
+; RUN: llc -O0 -mtriple=spirv-unknown-unknown %s -o - | FileCheck %s
+; RUN: %if spirv-tools %{ llc -O0 -mtriple=spirv-unknown-unknown %s -o - -filetype=obj | spirv-val %}
+
+; Make sure SPIRV operation function calls for lerp are generated as FMix
+
+; CHECK-DAG: %[[#op_ext_glsl:]] = OpExtInstImport "GLSL.std.450"
+; CHECK-DAG: %[[#float_32:]] = OpTypeFloat 32
+; CHECK-DAG: %[[#float_16:]] = OpTypeFloat 16
+; CHECK-DAG: %[[#vec4_float_16:]] = OpTypeVector %[[#float_16]] 4
+; CHECK-DAG: %[[#vec4_float_32:]] = OpTypeVector %[[#float_32]] 4
+
+define noundef half @lerp_half(half noundef %a, half noundef %b, half noundef %c) {
+entry:
+  ; CHECK: %[[#arg0:]] = OpFunctionParameter %[[#]]
+  ; CHECK: %[[#arg1:]] = OpFunctionParameter %[[#]]
+  ; CHECK: %[[#arg2:]] = OpFunctionParameter %[[#]]
+  ; CHECK: %[[#]] = OpExtInst %[[#float_16:]] %[[#op_ext_glsl:]] FMix %[[#arg0:]] %[[#arg1:]] %[[#arg2:]]
+  %hlsl.lerp = call half @llvm.spv.lerp.f16(half %a, half %b, half %c)
+  ret half %hlsl.lerp
+}
+
+
+define noundef float @lerp_float(float noundef %a, float noundef %b, float noundef %c) {
+entry:
+  ; CHECK: %[[#arg0:]] = OpFunctionParameter %[[#]]
+  ; CHECK: %[[#arg1:]] = OpFunctionParameter %[[#]]
+  ; CHECK: %[[#arg2:]] = OpFunctionParameter %[[#]]
+  ; CHECK: %[[#]] = OpExtInst %[[#float_32:]] %[[#op_ext_glsl:]] FMix %[[#arg0:]] %[[#arg1:]] %[[#arg2:]]
+  %hlsl.lerp = call float @llvm.spv.lerp.f32(float %a, float %b, float %c)
+  ret float %hlsl.lerp
+}
+
+define noundef <4 x half> @lerp_half4(<4 x half> noundef %a, <4 x half> noundef %b, <4 x half> noundef %c) {
+entry:
+  ; CHECK: %[[#arg0:]] = OpFunctionParameter %[[#]]
+  ; CHECK: %[[#arg1:]] = OpFunctionParameter %[[#]]
+  ; CHECK: %[[#arg2:]] = OpFunctionParameter %[[#]]
+  ; CHECK: %[[#]] = OpExtInst %[[#vec4_float_16:]] %[[#op_ext_glsl:]] FMix %[[#arg0:]] %[[#arg1:]] %[[#arg2:]]
+  %hlsl.lerp = call <4 x half> @llvm.spv.lerp.v4f16(<4 x half> %a, <4 x half> %b, <4 x half> %c)
+  ret <4 x half> %hlsl.lerp
+}
+
+define noundef <4 x float> @lerp_float4(<4 x float> noundef %a, <4 x float> noundef %b, <4 x float> noundef %c) {
+entry:
+  ; CHECK: %[[#arg0:]] = OpFunctionParameter %[[#]]
+  ; CHECK: %[[#arg1:]] = OpFunctionParameter %[[#]]
+  ; CHECK: %[[#arg2:]] = OpFunctionParameter %[[#]]
+  ; CHECK: %[[#]] = OpExtInst %[[#vec4_float_32:]] %[[#op_ext_glsl:]] FMix %[[#arg0:]] %[[#arg1:]] %[[#arg2:]]
+  %hlsl.lerp = call <4 x float> @llvm.spv.lerp.v4f32(<4 x float> %a, <4 x float> %b, <4 x float> %c)
+  ret <4 x float> %hlsl.lerp
+}
+
+declare half @llvm.spv.lerp.f16(half, half, half)
+declare float @llvm.spv.lerp.f32(float, float, float)
+declare <4 x half> @llvm.spv.lerp.v4f16(<4 x half>, <4 x half>, <4 x half>)
+declare <4 x float> @llvm.spv.lerp.v4f32(<4 x float>, <4 x float>, <4 x float>)

coopp
coopp approved these changes Apr 16, 2024
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Looks good to me.

@VyacheslavLevytskyy
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LGTM, just one question about documentation

@farzonl farzonl mentioned this pull request Apr 22, 2024
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@farzonl farzonl merged commit c4c54af into llvm:main Apr 22, 2024
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@farzonl farzonl deleted the spirv-lerp-fmix-lowering branch April 24, 2024 14:22
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@coopp coopp coopp approved these changes

@VyacheslavLevytskyy VyacheslavLevytskyy VyacheslavLevytskyy approved these changes

@sudonatalie sudonatalie Awaiting requested review from sudonatalie

@Keenuts Keenuts Awaiting requested review from Keenuts

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Labels
backend:SPIR-V clang:codegen clang Clang issues not falling into any other category HLSL HLSL Language Support llvm:ir
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HLSL Support
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[SPIRV][HLSL] Implement lerp lowering
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@farzonl @llvmbot @VyacheslavLevytskyy @coopp