[MLIR]Add support for Arith MAX & MIN operations

There are some of this supported in various places, but the
basic conversion of single operations to LLVM was not supported.

Adding this to allow Flang to use these.

Reviewed By: bondhugula

Differential Revision: https://reviews.llvm.org/D131912

mlir/lib/Conversion/ArithmeticToLLVM/ArithmeticToLLVM.cpp

@@ -68,6 +68,18 @@ using BitcastOpLowering =
     VectorConvertToLLVMPattern<arith::BitcastOp, LLVM::BitcastOp>;
 using SelectOpLowering =
     VectorConvertToLLVMPattern<arith::SelectOp, LLVM::SelectOp>;
+using MaxFOpLowering =
+    VectorConvertToLLVMPattern<arith::MaxFOp, LLVM::MaxNumOp>;
+using MaxSIOpLowering =
+    VectorConvertToLLVMPattern<arith::MaxSIOp, LLVM::SMaxOp>;
+using MaxUIOpLowering =
+    VectorConvertToLLVMPattern<arith::MaxUIOp, LLVM::UMaxOp>;
+using MinFOpLowering =
+    VectorConvertToLLVMPattern<arith::MinFOp, LLVM::MinNumOp>;
+using MinSIOpLowering =
+    VectorConvertToLLVMPattern<arith::MinSIOp, LLVM::SMinOp>;
+using MinUIOpLowering =
+    VectorConvertToLLVMPattern<arith::MinUIOp, LLVM::UMinOp>;
 
 //===----------------------------------------------------------------------===//
 // Op Lowering Patterns
@@ -321,7 +333,13 @@ void mlir::arith::populateArithmeticToLLVMConversionPatterns(
     BitcastOpLowering,
     CmpIOpLowering,
     CmpFOpLowering,
-    SelectOpLowering
+    SelectOpLowering,
+    MaxFOpLowering,
+    MaxUIOpLowering,
+    MaxSIOpLowering,
+    MinFOpLowering,
+    MinUIOpLowering,
+    MinSIOpLowering
   >(converter);
   // clang-format on
 }

mlir/test/Conversion/ArithmeticToLLVM/arith-to-llvm.mlir

@@ -383,3 +383,27 @@ func.func @select(%arg0 : i1, %arg1 : i32, %arg2 : i32) -> i32 {
   %0 = arith.select %arg0, %arg1, %arg2 : i32
   return %0 : i32
 }
+
+// -----
+
+// CHECK-LABEL: @minmaxi
+func.func @minmaxi(%arg0 : i32, %arg1 : i32) -> i32 {
+  // CHECK: = "llvm.intr.smin"(%arg0, %arg1) : (i32, i32) -> i32
+  %0 = arith.minsi %arg0, %arg1 : i32
+  // CHECK: = "llvm.intr.smax"(%arg0, %arg1) : (i32, i32) -> i32
+  %1 = arith.maxsi %arg0, %arg1 : i32
+  // CHECK: = "llvm.intr.umin"(%arg0, %arg1) : (i32, i32) -> i32
+  %2 = arith.minui %arg0, %arg1 : i32
+  // CHECK: = "llvm.intr.umax"(%arg0, %arg1) : (i32, i32) -> i32
+  %3 = arith.maxui %arg0, %arg1 : i32
+  return %0 : i32
+}
+
+// CHECK-LABEL: @minmaxf
+func.func @minmaxf(%arg0 : f32, %arg1 : f32) -> f32 {
+  // CHECK: = "llvm.intr.minnum"(%arg0, %arg1) : (f32, f32) -> f32
+  %0 = arith.minf %arg0, %arg1 : f32
+  // CHECK: = "llvm.intr.maxnum"(%arg0, %arg1) : (f32, f32) -> f32
+  %1 = arith.maxf %arg0, %arg1 : f32
+  return %0 : f32
+}