diff --git a/mlir/include/mlir/Dialect/LLVMIR/LLVMIntrinsicOps.td b/mlir/include/mlir/Dialect/LLVMIR/LLVMIntrinsicOps.td
--- a/mlir/include/mlir/Dialect/LLVMIR/LLVMIntrinsicOps.td
+++ b/mlir/include/mlir/Dialect/LLVMIR/LLVMIntrinsicOps.td
@@ -867,19 +867,19 @@
 // CallIntrinsicOp
 //===--------------------------------------------------------------------===//
 
-def LLVM_CallIntrinsicOp : LLVM_Op<"call_intrinsic"> {
+def LLVM_CallIntrinsicOp : LLVM_Op<"call_intrinsic", [DeclareOpInterfaceMethods<FastmathFlagsInterface>]> {
   let summary = "Call to an LLVM intrinsic function.";
   let description = [{
     Call the specified llvm intrinsic. If the intrinsic is overloaded, use
     the MLIR function type of this op to determine which intrinsic to call.
     }];
-  let arguments = (ins StrAttr:$intrin, Variadic<LLVM_Type>:$args);
+  let arguments = (ins StrAttr:$intrin, Variadic<LLVM_Type>:$args, DefaultValuedAttr<LLVM_FastmathFlagsAttr, "{}">:$fastmathFlags);
   let results = (outs Variadic<LLVM_Type>:$results);
   let llvmBuilder = [{
     return convertCallLLVMIntrinsicOp(op, builder, moduleTranslation);
   }];
   let assemblyFormat = [{
-    $intrin `(` $args `)` `:` functional-type($args, $results) attr-dict
+    $intrin `(` $args `)` `:` functional-type($args, $results) custom<LLVMOpAttrs>(attr-dict)
   }];
 }
 
diff --git a/mlir/lib/Target/LLVMIR/Dialect/LLVMIR/LLVMToLLVMIRTranslation.cpp b/mlir/lib/Target/LLVMIR/Dialect/LLVMIR/LLVMToLLVMIRTranslation.cpp
--- a/mlir/lib/Target/LLVMIR/Dialect/LLVMIR/LLVMToLLVMIRTranslation.cpp
+++ b/mlir/lib/Target/LLVMIR/Dialect/LLVMIR/LLVMToLLVMIRTranslation.cpp
@@ -114,6 +114,9 @@
   } else {
     fn = llvm::Intrinsic::getDeclaration(module, id, {});
   }
+  Operation* op2 = op;
+  if (auto fmf = dyn_cast<FastmathFlagsInterface>(op2))
+    builder.setFastMathFlags(getFastmathFlags(fmf));
 
   auto *inst =
       builder.CreateCall(fn, moduleTranslation.lookupValues(op.getOperands()));
diff --git a/mlir/test/Dialect/LLVMIR/call-intrin.mlir b/mlir/test/Dialect/LLVMIR/call-intrin.mlir
--- a/mlir/test/Dialect/LLVMIR/call-intrin.mlir
+++ b/mlir/test/Dialect/LLVMIR/call-intrin.mlir
@@ -11,7 +11,7 @@
 llvm.func @round_sse41() -> vector<4xf32> {
     %0 = llvm.mlir.constant(1 : i32) : i32
     %1 = llvm.mlir.constant(dense<0.2> : vector<4xf32>) : vector<4xf32>
-    %res = llvm.call_intrinsic "llvm.x86.sse41.round.ss"(%1, %1, %0) : (vector<4xf32>, vector<4xf32>, i32) -> vector<4xf32> {}
+    %res = llvm.call_intrinsic "llvm.x86.sse41.round.ss"(%1, %1, %0) : (vector<4xf32>, vector<4xf32>, i32) -> vector<4xf32> {fastmathFlags = #llvm.fastmath<reassoc>}
     llvm.return %res: vector<4xf32>
 }