[Mlir-commits] [mlir] [mlir][SPIR-V] Add SPIRVToLLVM conversion for SNegate (PR #206950)

[Arseniy Obolenskiy]

https://github.com/aobolensk updated https://github.com/llvm/llvm-project/pull/206950

>From 187cd538f98c32b897f1d8839a38a3b6915917a1 Mon Sep 17 00:00:00 2001
From: Arseniy Obolenskiy <arseniy.obolenskiy at amd.com>
Date: Wed, 1 Jul 2026 13:12:30 +0200
Subject: [PATCH 1/2] [mlir][SPIR-V] Add SPIRVToLLVM conversion for SNegate

---
 .../Conversion/SPIRVToLLVM/SPIRVToLLVM.cpp    | 31 ++++++++++++++++++-
 .../SPIRVToLLVM/arithmetic-ops-to-llvm.mlir   | 20 ++++++++++++
 2 files changed, 50 insertions(+), 1 deletion(-)

diff --git a/mlir/lib/Conversion/SPIRVToLLVM/SPIRVToLLVM.cpp b/mlir/lib/Conversion/SPIRVToLLVM/SPIRVToLLVM.cpp
index c43415b27b1b3..610c052b64ea7 100644
--- a/mlir/lib/Conversion/SPIRVToLLVM/SPIRVToLLVM.cpp
+++ b/mlir/lib/Conversion/SPIRVToLLVM/SPIRVToLLVM.cpp
@@ -921,6 +921,35 @@ class InverseSqrtPattern
   }
 };
 
+/// Converts `spirv.SNegate` to `0 - x`.
+class SNegatePattern : public SPIRVToLLVMConversion<spirv::SNegateOp> {
+public:
+  using SPIRVToLLVMConversion<spirv::SNegateOp>::SPIRVToLLVMConversion;
+
+  LogicalResult
+  matchAndRewrite(spirv::SNegateOp op, OpAdaptor adaptor,
+                  ConversionPatternRewriter &rewriter) const override {
+    auto srcType = op.getType();
+    auto dstType = getTypeConverter()->convertType(srcType);
+    if (!dstType)
+      return rewriter.notifyMatchFailure(op, "type conversion failed");
+
+    Location loc = op.getLoc();
+    auto vecSrcType = dyn_cast<VectorType>(srcType);
+    IntegerAttr zeroAttr = rewriter.getIntegerAttr(
+        cast<IntegerType>(getElementTypeOrSelf(srcType)), 0);
+    Value zero;
+    if (vecSrcType)
+      zero = LLVM::ConstantOp::create(
+          rewriter, loc, dstType, SplatElementsAttr::get(vecSrcType, zeroAttr));
+    else
+      zero = LLVM::ConstantOp::create(rewriter, loc, dstType, zeroAttr);
+    rewriter.replaceOpWithNewOp<LLVM::SubOp>(op, dstType, zero,
+                                             adaptor.getOperand());
+    return success();
+  }
+};
+
 /// Converts `spirv.Load` and `spirv.Store` to LLVM dialect.
 template <typename SPIRVOp>
 class LoadStorePattern : public SPIRVToLLVMConversion<SPIRVOp> {
@@ -1824,7 +1853,7 @@ void mlir::populateSPIRVToLLVMConversionPatterns(
       DirectConversionPattern<spirv::SDivOp, LLVM::SDivOp>,
       DirectConversionPattern<spirv::SRemOp, LLVM::SRemOp>,
       DirectConversionPattern<spirv::UDivOp, LLVM::UDivOp>,
-      DirectConversionPattern<spirv::UModOp, LLVM::URemOp>,
+      DirectConversionPattern<spirv::UModOp, LLVM::URemOp>, SNegatePattern,
 
       // Bitwise ops
       BitFieldInsertPattern, BitFieldUExtractPattern, BitFieldSExtractPattern,
diff --git a/mlir/test/Conversion/SPIRVToLLVM/arithmetic-ops-to-llvm.mlir b/mlir/test/Conversion/SPIRVToLLVM/arithmetic-ops-to-llvm.mlir
index dbbf8610afb4d..ee9c06fbb10e1 100644
--- a/mlir/test/Conversion/SPIRVToLLVM/arithmetic-ops-to-llvm.mlir
+++ b/mlir/test/Conversion/SPIRVToLLVM/arithmetic-ops-to-llvm.mlir
@@ -233,3 +233,23 @@ spirv.func @srem_vector(%arg0: vector<4xi32>, %arg1: vector<4xi32>) "None" {
   %0 = spirv.SRem %arg0, %arg1 : vector<4xi32>
   spirv.Return
 }
+
+//===----------------------------------------------------------------------===//
+// spirv.SNegate
+//===----------------------------------------------------------------------===//
+
+// CHECK-LABEL: @snegate_scalar
+spirv.func @snegate_scalar(%arg0: i32) "None" {
+  // CHECK: %[[ZERO:.*]] = llvm.mlir.constant(0 : i32) : i32
+  // CHECK: llvm.sub %[[ZERO]], %{{.*}} : i32
+  %0 = spirv.SNegate %arg0 : i32
+  spirv.Return
+}
+
+// CHECK-LABEL: @snegate_vector
+spirv.func @snegate_vector(%arg0: vector<4xi32>) "None" {
+  // CHECK: %[[ZERO:.*]] = llvm.mlir.constant(dense<0> : vector<4xi32>) : vector<4xi32>
+  // CHECK: llvm.sub %[[ZERO]], %{{.*}} : vector<4xi32>
+  %0 = spirv.SNegate %arg0 : vector<4xi32>
+  spirv.Return
+}

>From 204b7a856af639ca4bb46501848cabdcef02e393 Mon Sep 17 00:00:00 2001
From: Arseniy Obolenskiy <arseniy.obolenskiy at amd.com>
Date: Fri, 10 Jul 2026 13:45:23 +0200
Subject: [PATCH 2/2] Address comments

---
 .../Conversion/SPIRVToLLVM/SPIRVToLLVM.cpp    | 34 +++++++++----------
 1 file changed, 17 insertions(+), 17 deletions(-)

diff --git a/mlir/lib/Conversion/SPIRVToLLVM/SPIRVToLLVM.cpp b/mlir/lib/Conversion/SPIRVToLLVM/SPIRVToLLVM.cpp
index 96acea0f4f127..a8bee01b08d26 100644
--- a/mlir/lib/Conversion/SPIRVToLLVM/SPIRVToLLVM.cpp
+++ b/mlir/lib/Conversion/SPIRVToLLVM/SPIRVToLLVM.cpp
@@ -90,17 +90,22 @@ static IntegerAttr minusOneIntegerAttribute(Type type, Builder builder) {
   return builder.getIntegerAttr(integerType, -1);
 }
 
+/// Creates `llvm.mlir.constant` with a scalar or vector integer value,
+/// broadcasting `scalarAttr` across the vector if `srcType` is a vector.
+static Value createIntegerConstant(Location loc, Type srcType, Type dstType,
+                                   PatternRewriter &rewriter,
+                                   IntegerAttr scalarAttr) {
+  if (auto vecType = dyn_cast<VectorType>(srcType))
+    return LLVM::ConstantOp::create(
+        rewriter, loc, dstType, SplatElementsAttr::get(vecType, scalarAttr));
+  return LLVM::ConstantOp::create(rewriter, loc, dstType, scalarAttr);
+}
+
 /// Creates `llvm.mlir.constant` with all bits set for the given type.
 static Value createConstantAllBitsSet(Location loc, Type srcType, Type dstType,
                                       PatternRewriter &rewriter) {
-  if (isa<VectorType>(srcType)) {
-    return LLVM::ConstantOp::create(
-        rewriter, loc, dstType,
-        SplatElementsAttr::get(cast<ShapedType>(srcType),
-                               minusOneIntegerAttribute(srcType, rewriter)));
-  }
-  return LLVM::ConstantOp::create(rewriter, loc, dstType,
-                                  minusOneIntegerAttribute(srcType, rewriter));
+  return createIntegerConstant(loc, srcType, dstType, rewriter,
+                               minusOneIntegerAttribute(srcType, rewriter));
 }
 
 /// Creates `llvm.mlir.constant` with a floating-point scalar or vector value.
@@ -929,21 +934,16 @@ class SNegatePattern : public SPIRVToLLVMConversion<spirv::SNegateOp> {
   LogicalResult
   matchAndRewrite(spirv::SNegateOp op, OpAdaptor adaptor,
                   ConversionPatternRewriter &rewriter) const override {
-    auto srcType = op.getType();
-    auto dstType = getTypeConverter()->convertType(srcType);
+    Type srcType = op.getType();
+    Type dstType = getTypeConverter()->convertType(srcType);
     if (!dstType)
       return rewriter.notifyMatchFailure(op, "type conversion failed");
 
     Location loc = op.getLoc();
-    auto vecSrcType = dyn_cast<VectorType>(srcType);
     IntegerAttr zeroAttr = rewriter.getIntegerAttr(
         cast<IntegerType>(getElementTypeOrSelf(srcType)), 0);
-    Value zero;
-    if (vecSrcType)
-      zero = LLVM::ConstantOp::create(
-          rewriter, loc, dstType, SplatElementsAttr::get(vecSrcType, zeroAttr));
-    else
-      zero = LLVM::ConstantOp::create(rewriter, loc, dstType, zeroAttr);
+    Value zero =
+        createIntegerConstant(loc, srcType, dstType, rewriter, zeroAttr);
     rewriter.replaceOpWithNewOp<LLVM::SubOp>(op, dstType, zero,
                                              adaptor.getOperand());
     return success();