[Mlir-commits] [mlir] [mlir][SPIR-V] Add SPIRVToLLVM conversion for GL.Fract (PR #206951)

[Arseniy Obolenskiy]

https://github.com/aobolensk created https://github.com/llvm/llvm-project/pull/206951

None

>From 0c27ffa07eb9b334cbc1bd5e4df2a94abd4e2643 Mon Sep 17 00:00:00 2001
From: Arseniy Obolenskiy <arseniy.obolenskiy at amd.com>
Date: Wed, 1 Jul 2026 13:15:31 +0200
Subject: [PATCH] [mlir][SPIR-V] Add SPIRVToLLVM conversion for GL.Fract

---
 .../Conversion/SPIRVToLLVM/SPIRVToLLVM.cpp    | 22 ++++++++++++++++++-
 .../SPIRVToLLVM/gl-ops-to-llvm.mlir           | 15 +++++++++++++
 2 files changed, 36 insertions(+), 1 deletion(-)

diff --git a/mlir/lib/Conversion/SPIRVToLLVM/SPIRVToLLVM.cpp b/mlir/lib/Conversion/SPIRVToLLVM/SPIRVToLLVM.cpp
index c43415b27b1b3..c9eba35cf0939 100644
--- a/mlir/lib/Conversion/SPIRVToLLVM/SPIRVToLLVM.cpp
+++ b/mlir/lib/Conversion/SPIRVToLLVM/SPIRVToLLVM.cpp
@@ -1564,6 +1564,26 @@ class SAbsPattern : public SPIRVToLLVMConversion<spirv::GLSAbsOp> {
   }
 };
 
+/// Converts `spirv.GL.Fract` to `x - floor(x)`.
+class FractPattern : public SPIRVToLLVMConversion<spirv::GLFractOp> {
+public:
+  using SPIRVToLLVMConversion<spirv::GLFractOp>::SPIRVToLLVMConversion;
+
+  LogicalResult
+  matchAndRewrite(spirv::GLFractOp op, OpAdaptor adaptor,
+                  ConversionPatternRewriter &rewriter) const override {
+    auto dstType = getTypeConverter()->convertType(op.getType());
+    if (!dstType)
+      return rewriter.notifyMatchFailure(op, "type conversion failed");
+
+    Location loc = op.getLoc();
+    Value operand = adaptor.getOperand();
+    Value floored = LLVM::FFloorOp::create(rewriter, loc, dstType, operand);
+    rewriter.replaceOpWithNewOp<LLVM::FSubOp>(op, dstType, operand, floored);
+    return success();
+  }
+};
+
 class VariablePattern : public SPIRVToLLVMConversion<spirv::VariableOp> {
 public:
   using SPIRVToLLVMConversion<spirv::VariableOp>::SPIRVToLLVMConversion;
@@ -1916,7 +1936,7 @@ void mlir::populateSPIRVToLLVMConversionPatterns(
       DirectConversionPattern<spirv::GLAsinOp, LLVM::ASinOp>,
       DirectConversionPattern<spirv::GLAcosOp, LLVM::ACosOp>,
       DirectConversionPattern<spirv::GLAtanOp, LLVM::ATanOp>,
-      InverseSqrtPattern, SAbsPattern, TanPattern, TanhPattern,
+      InverseSqrtPattern, SAbsPattern, TanPattern, TanhPattern, FractPattern,
 
       // OpenCL extended instruction set ops
       DirectConversionPattern<spirv::CLCeilOp, LLVM::FCeilOp>,
diff --git a/mlir/test/Conversion/SPIRVToLLVM/gl-ops-to-llvm.mlir b/mlir/test/Conversion/SPIRVToLLVM/gl-ops-to-llvm.mlir
index ffa47efbf9213..042b68bef9dcd 100644
--- a/mlir/test/Conversion/SPIRVToLLVM/gl-ops-to-llvm.mlir
+++ b/mlir/test/Conversion/SPIRVToLLVM/gl-ops-to-llvm.mlir
@@ -361,3 +361,18 @@ spirv.func @asin_acos_atan(%arg0: f32, %arg1: vector<3xf16>) "None" {
   %2 = spirv.GL.Atan %arg0 : f32
   spirv.Return
 }
+
+//===----------------------------------------------------------------------===//
+// spirv.GL.Fract
+//===----------------------------------------------------------------------===//
+
+// CHECK-LABEL: @fract
+spirv.func @fract(%arg0: f32, %arg1: vector<3xf16>) "None" {
+  // CHECK: %[[FLOOR:.*]] = llvm.intr.floor(%{{.*}}) : (f32) -> f32
+  // CHECK: llvm.fsub %{{.*}}, %[[FLOOR]] : f32
+  %0 = spirv.GL.Fract %arg0 : f32
+  // CHECK: %[[FLOORV:.*]] = llvm.intr.floor(%{{.*}}) : (vector<3xf16>) -> vector<3xf16>
+  // CHECK: llvm.fsub %{{.*}}, %[[FLOORV]] : vector<3xf16>
+  %1 = spirv.GL.Fract %arg1 : vector<3xf16>
+  spirv.Return
+}