[Mlir-commits] [mlir] 31de6f2 - [mlir][SPIR-V] Add SPIRVToLLVM conversions for GL.FSign and GL.SSign (#206934)

[llvmlistbot at llvm.org]

Author: Arseniy Obolenskiy
Date: 2026-07-29T15:07:37+02:00
New Revision: 31de6f2c4b4d38bbcabea7a1eeb000f90f368604

URL: https://github.com/llvm/llvm-project/commit/31de6f2c4b4d38bbcabea7a1eeb000f90f368604
DIFF: https://github.com/llvm/llvm-project/commit/31de6f2c4b4d38bbcabea7a1eeb000f90f368604.diff

LOG: [mlir][SPIR-V] Add SPIRVToLLVM conversions for GL.FSign and GL.SSign (#206934)

Added: 
    

Modified: 
    mlir/lib/Conversion/SPIRVToLLVM/SPIRVToLLVM.cpp
    mlir/test/Conversion/SPIRVToLLVM/gl-ops-to-llvm.mlir

Removed: 
    


################################################################################
diff  --git a/mlir/lib/Conversion/SPIRVToLLVM/SPIRVToLLVM.cpp b/mlir/lib/Conversion/SPIRVToLLVM/SPIRVToLLVM.cpp
index db8a1e8c9ef38..c272a91f0ed76 100644
--- a/mlir/lib/Conversion/SPIRVToLLVM/SPIRVToLLVM.cpp
+++ b/mlir/lib/Conversion/SPIRVToLLVM/SPIRVToLLVM.cpp
@@ -1752,6 +1752,59 @@ class ScalePattern : public SPIRVToLLVMConversion<SPIRVOp> {
   double scale;
 };
 
+/// Converts `spirv.GL.FSign`/`spirv.GL.SSign` to a sign(x) sequence that maps
+/// the operand to -1/0/1 using two comparisons and two selects. The `isFloat`
+/// flag selects between floating-point and integer comparisons/constants.
+template <typename SPIRVOp, bool isFloat>
+class SignPattern : public SPIRVToLLVMConversion<SPIRVOp> {
+public:
+  using SPIRVToLLVMConversion<SPIRVOp>::SPIRVToLLVMConversion;
+
+  LogicalResult
+  matchAndRewrite(SPIRVOp op, typename SPIRVOp::Adaptor adaptor,
+                  ConversionPatternRewriter &rewriter) const override {
+    Type srcType = op.getType();
+    Type dstType = this->getTypeConverter()->convertType(srcType);
+    if (!dstType)
+      return rewriter.notifyMatchFailure(op, "type conversion failed");
+
+    Location loc = op.getLoc();
+    Value operand = adaptor.getOperand();
+    auto vecSrcType = dyn_cast<VectorType>(srcType);
+    Type i1Type = rewriter.getI1Type();
+    Type cmpType =
+        vecSrcType ? VectorType::get(vecSrcType.getShape(), i1Type) : i1Type;
+
+    Value zero, one, minusOne, gt, lt;
+    if constexpr (isFloat) {
+      zero = createFPConstant(loc, srcType, dstType, rewriter, 0.0);
+      one = createFPConstant(loc, srcType, dstType, rewriter, 1.0);
+      minusOne = createFPConstant(loc, srcType, dstType, rewriter, -1.0);
+      gt = LLVM::FCmpOp::create(rewriter, loc, cmpType,
+                                LLVM::FCmpPredicate::ogt, operand, zero);
+      lt = LLVM::FCmpOp::create(rewriter, loc, cmpType,
+                                LLVM::FCmpPredicate::olt, operand, zero);
+    } else {
+      auto intElemType = cast<IntegerType>(getElementTypeOrSelf(srcType));
+      zero = createIntegerConstant(loc, srcType, dstType, rewriter,
+                                   rewriter.getIntegerAttr(intElemType, 0));
+      one = createIntegerConstant(loc, srcType, dstType, rewriter,
+                                  rewriter.getIntegerAttr(intElemType, 1));
+      minusOne = createConstantAllBitsSet(loc, srcType, dstType, rewriter);
+      gt = LLVM::ICmpOp::create(rewriter, loc, cmpType,
+                                LLVM::ICmpPredicate::sgt, operand, zero);
+      lt = LLVM::ICmpOp::create(rewriter, loc, cmpType,
+                                LLVM::ICmpPredicate::slt, operand, zero);
+    }
+
+    Value negOrZero =
+        LLVM::SelectOp::create(rewriter, loc, dstType, lt, minusOne, zero);
+    rewriter.replaceOpWithNewOp<LLVM::SelectOp>(op, dstType, gt, one,
+                                                negOrZero);
+    return success();
+  }
+};
+
 class VariablePattern : public SPIRVToLLVMConversion<spirv::VariableOp> {
 public:
   using SPIRVToLLVMConversion<spirv::VariableOp>::SPIRVToLLVMConversion;
@@ -2116,7 +2169,9 @@ void mlir::populateSPIRVToLLVMConversionPatterns(
       DirectConversionPattern<spirv::GLAtanOp, LLVM::ATanOp>,
       DirectConversionPattern<spirv::GLTanOp, LLVM::TanOp>,
       DirectConversionPattern<spirv::GLTanhOp, LLVM::TanhOp>,
-      InverseSqrtPattern, SAbsPattern, FractPattern, GLFMixPattern,
+      InverseSqrtPattern, SAbsPattern, FractPattern,
+      SignPattern<spirv::GLFSignOp, /*isFloat=*/true>,
+      SignPattern<spirv::GLSSignOp, /*isFloat=*/false>, GLFMixPattern,
 
       // 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 08c7947861cb4..e0deafd2824b9 100644
--- a/mlir/test/Conversion/SPIRVToLLVM/gl-ops-to-llvm.mlir
+++ b/mlir/test/Conversion/SPIRVToLLVM/gl-ops-to-llvm.mlir
@@ -469,6 +469,60 @@ spirv.func @fract(%arg0: f32, %arg1: vector<3xf16>) "None" {
   spirv.Return
 }
 
+//===----------------------------------------------------------------------===//
+// spirv.GL.FSign
+//===----------------------------------------------------------------------===//
+
+// CHECK-LABEL: @fsign_scalar
+spirv.func @fsign_scalar(%arg0: f32) "None" {
+  // CHECK: %[[ZERO:.*]] = llvm.mlir.constant(0.000000e+00 : f32) : f32
+  // CHECK: %[[ONE:.*]] = llvm.mlir.constant(1.000000e+00 : f32) : f32
+  // CHECK: %[[MONE:.*]] = llvm.mlir.constant(-1.000000e+00 : f32) : f32
+  // CHECK: %[[GT:.*]] = llvm.fcmp "ogt" %{{.*}}, %[[ZERO]] : f32
+  // CHECK: %[[LT:.*]] = llvm.fcmp "olt" %{{.*}}, %[[ZERO]] : f32
+  // CHECK: %[[SEL0:.*]] = llvm.select %[[LT]], %[[MONE]], %[[ZERO]] : i1, f32
+  // CHECK: llvm.select %[[GT]], %[[ONE]], %[[SEL0]] : i1, f32
+  %0 = spirv.GL.FSign %arg0 : f32
+  spirv.Return
+}
+
+// CHECK-LABEL: @fsign_vector
+spirv.func @fsign_vector(%arg0: vector<4xf32>) "None" {
+  // CHECK: %[[GT:.*]] = llvm.fcmp "ogt" %{{.*}}, %{{.*}} : vector<4xf32>
+  // CHECK: %[[LT:.*]] = llvm.fcmp "olt" %{{.*}}, %{{.*}} : vector<4xf32>
+  // CHECK: %[[SEL0:.*]] = llvm.select %[[LT]], %{{.*}}, %{{.*}} : vector<4xi1>, vector<4xf32>
+  // CHECK: llvm.select %[[GT]], %{{.*}}, %[[SEL0]] : vector<4xi1>, vector<4xf32>
+  %0 = spirv.GL.FSign %arg0 : vector<4xf32>
+  spirv.Return
+}
+
+//===----------------------------------------------------------------------===//
+// spirv.GL.SSign
+//===----------------------------------------------------------------------===//
+
+// CHECK-LABEL: @ssign_scalar
+spirv.func @ssign_scalar(%arg0: i32) "None" {
+  // CHECK: %[[ZERO:.*]] = llvm.mlir.constant(0 : i32) : i32
+  // CHECK: %[[ONE:.*]] = llvm.mlir.constant(1 : i32) : i32
+  // CHECK: %[[MONE:.*]] = llvm.mlir.constant(-1 : i32) : i32
+  // CHECK: %[[GT:.*]] = llvm.icmp "sgt" %{{.*}}, %[[ZERO]] : i32
+  // CHECK: %[[LT:.*]] = llvm.icmp "slt" %{{.*}}, %[[ZERO]] : i32
+  // CHECK: %[[SEL0:.*]] = llvm.select %[[LT]], %[[MONE]], %[[ZERO]] : i1, i32
+  // CHECK: llvm.select %[[GT]], %[[ONE]], %[[SEL0]] : i1, i32
+  %0 = spirv.GL.SSign %arg0 : i32
+  spirv.Return
+}
+
+// CHECK-LABEL: @ssign_vector
+spirv.func @ssign_vector(%arg0: vector<4xi32>) "None" {
+  // CHECK: %[[GT:.*]] = llvm.icmp "sgt" %{{.*}}, %{{.*}} : vector<4xi32>
+  // CHECK: %[[LT:.*]] = llvm.icmp "slt" %{{.*}}, %{{.*}} : vector<4xi32>
+  // CHECK: %[[SEL0:.*]] = llvm.select %[[LT]], %{{.*}}, %{{.*}} : vector<4xi1>, vector<4xi32>
+  // CHECK: llvm.select %[[GT]], %{{.*}}, %[[SEL0]] : vector<4xi1>, vector<4xi32>
+  %0 = spirv.GL.SSign %arg0 : vector<4xi32>
+  spirv.Return
+}
+
 //===----------------------------------------------------------------------===//
 // spirv.GL.FMix
 //===----------------------------------------------------------------------===//