[Mlir-commits] [mlir] [mlir][SPIR-V] Add SPIRVToLLVM conversions for GL.FMix and CL.mix (PR #206935)

[Arseniy Obolenskiy]

https://github.com/aobolensk updated https://github.com/llvm/llvm-project/pull/206935

>From 4fa5c4ca4a5a4333743f1fc3afa38979d20a176a Mon Sep 17 00:00:00 2001
From: Arseniy Obolenskiy <arseniy.obolenskiy at amd.com>
Date: Wed, 1 Jul 2026 11:54:35 +0200
Subject: [PATCH] [mlir][SPIR-V] Add SPIRVToLLVM conversions for GL.FMix and
 CL.mix

---
 .../Conversion/SPIRVToLLVM/SPIRVToLLVM.cpp    | 27 +++++++++++++++++++
 .../SPIRVToLLVM/cl-ops-to-llvm.mlir           | 20 ++++++++++++++
 .../SPIRVToLLVM/gl-ops-to-llvm.mlir           | 20 ++++++++++++++
 3 files changed, 67 insertions(+)

diff --git a/mlir/lib/Conversion/SPIRVToLLVM/SPIRVToLLVM.cpp b/mlir/lib/Conversion/SPIRVToLLVM/SPIRVToLLVM.cpp
index c43415b27b1b3..c3fff3b55587c 100644
--- a/mlir/lib/Conversion/SPIRVToLLVM/SPIRVToLLVM.cpp
+++ b/mlir/lib/Conversion/SPIRVToLLVM/SPIRVToLLVM.cpp
@@ -1564,6 +1564,31 @@ class SAbsPattern : public SPIRVToLLVMConversion<spirv::GLSAbsOp> {
   }
 };
 
+/// Converts `spirv.GL.FMix`/`spirv.CL.mix` to `fma(a, y - x, x)`, the linear
+/// blend `x * (1 - a) + y * a`. Operands are taken positionally because the GL
+/// and CL ops name their third operand differently (`a` vs. `z`).
+template <typename SPIRVOp>
+class MixPattern : public SPIRVToLLVMConversion<SPIRVOp> {
+public:
+  using SPIRVToLLVMConversion<SPIRVOp>::SPIRVToLLVMConversion;
+
+  LogicalResult
+  matchAndRewrite(SPIRVOp op, typename SPIRVOp::Adaptor adaptor,
+                  ConversionPatternRewriter &rewriter) const override {
+    auto dstType = this->getTypeConverter()->convertType(op.getType());
+    if (!dstType)
+      return rewriter.notifyMatchFailure(op, "type conversion failed");
+
+    Location loc = op.getLoc();
+    Value x = adaptor.getOperands()[0];
+    Value y = adaptor.getOperands()[1];
+    Value a = adaptor.getOperands()[2];
+    Value diff = LLVM::FSubOp::create(rewriter, loc, dstType, y, x);
+    rewriter.replaceOpWithNewOp<LLVM::FMAOp>(op, dstType, a, diff, x);
+    return success();
+  }
+};
+
 class VariablePattern : public SPIRVToLLVMConversion<spirv::VariableOp> {
 public:
   using SPIRVToLLVMConversion<spirv::VariableOp>::SPIRVToLLVMConversion;
@@ -1917,6 +1942,7 @@ void mlir::populateSPIRVToLLVMConversionPatterns(
       DirectConversionPattern<spirv::GLAcosOp, LLVM::ACosOp>,
       DirectConversionPattern<spirv::GLAtanOp, LLVM::ATanOp>,
       InverseSqrtPattern, SAbsPattern, TanPattern, TanhPattern,
+      MixPattern<spirv::GLFMixOp>,
 
       // OpenCL extended instruction set ops
       DirectConversionPattern<spirv::CLCeilOp, LLVM::FCeilOp>,
@@ -1950,6 +1976,7 @@ void mlir::populateSPIRVToLLVMConversionPatterns(
       DirectConversionPattern<spirv::CLSMinOp, LLVM::SMinOp>,
       DirectConversionPattern<spirv::CLUMaxOp, LLVM::UMaxOp>,
       DirectConversionPattern<spirv::CLUMinOp, LLVM::UMinOp>,
+      MixPattern<spirv::CLMixOp>,
 
       // Logical ops
       DirectConversionPattern<spirv::LogicalAndOp, LLVM::AndOp>,
diff --git a/mlir/test/Conversion/SPIRVToLLVM/cl-ops-to-llvm.mlir b/mlir/test/Conversion/SPIRVToLLVM/cl-ops-to-llvm.mlir
index f0568e1035cd9..a986be42a5437 100644
--- a/mlir/test/Conversion/SPIRVToLLVM/cl-ops-to-llvm.mlir
+++ b/mlir/test/Conversion/SPIRVToLLVM/cl-ops-to-llvm.mlir
@@ -99,3 +99,23 @@ spirv.func @cl_integer(%arg0: i32, %arg1: i32) "None" {
   %3 = spirv.CL.u_min %arg0, %arg1 : i32
   spirv.Return
 }
+
+//===----------------------------------------------------------------------===//
+// spirv.CL.mix
+//===----------------------------------------------------------------------===//
+
+// CHECK-LABEL: @mix_scalar
+spirv.func @mix_scalar(%x: f32, %y: f32, %a: f32) "None" {
+  // CHECK: %[[DIFF:.*]] = llvm.fsub %{{.*}}, %{{.*}} : f32
+  // CHECK: llvm.intr.fma(%{{.*}}, %[[DIFF]], %{{.*}}) : (f32, f32, f32) -> f32
+  %0 = spirv.CL.mix %x, %y, %a : f32
+  spirv.Return
+}
+
+// CHECK-LABEL: @mix_vector
+spirv.func @mix_vector(%x: vector<4xf32>, %y: vector<4xf32>, %a: vector<4xf32>) "None" {
+  // CHECK: %[[DIFF:.*]] = llvm.fsub %{{.*}}, %{{.*}} : vector<4xf32>
+  // CHECK: llvm.intr.fma(%{{.*}}, %[[DIFF]], %{{.*}}) : (vector<4xf32>, vector<4xf32>, vector<4xf32>) -> vector<4xf32>
+  %0 = spirv.CL.mix %x, %y, %a : vector<4xf32>
+  spirv.Return
+}
diff --git a/mlir/test/Conversion/SPIRVToLLVM/gl-ops-to-llvm.mlir b/mlir/test/Conversion/SPIRVToLLVM/gl-ops-to-llvm.mlir
index ffa47efbf9213..f405ef48c6fe1 100644
--- a/mlir/test/Conversion/SPIRVToLLVM/gl-ops-to-llvm.mlir
+++ b/mlir/test/Conversion/SPIRVToLLVM/gl-ops-to-llvm.mlir
@@ -361,3 +361,23 @@ spirv.func @asin_acos_atan(%arg0: f32, %arg1: vector<3xf16>) "None" {
   %2 = spirv.GL.Atan %arg0 : f32
   spirv.Return
 }
+
+//===----------------------------------------------------------------------===//
+// spirv.GL.FMix
+//===----------------------------------------------------------------------===//
+
+// CHECK-LABEL: @fmix_scalar
+spirv.func @fmix_scalar(%x: f32, %y: f32, %a: f32) "None" {
+  // CHECK: %[[DIFF:.*]] = llvm.fsub %{{.*}}, %{{.*}} : f32
+  // CHECK: llvm.intr.fma(%{{.*}}, %[[DIFF]], %{{.*}}) : (f32, f32, f32) -> f32
+  %0 = spirv.GL.FMix %x : f32, %y : f32, %a : f32 -> f32
+  spirv.Return
+}
+
+// CHECK-LABEL: @fmix_vector
+spirv.func @fmix_vector(%x: vector<4xf32>, %y: vector<4xf32>, %a: vector<4xf32>) "None" {
+  // CHECK: %[[DIFF:.*]] = llvm.fsub %{{.*}}, %{{.*}} : vector<4xf32>
+  // CHECK: llvm.intr.fma(%{{.*}}, %[[DIFF]], %{{.*}}) : (vector<4xf32>, vector<4xf32>, vector<4xf32>) -> vector<4xf32>
+  %0 = spirv.GL.FMix %x : vector<4xf32>, %y : vector<4xf32>, %a : vector<4xf32> -> vector<4xf32>
+  spirv.Return
+}