[MLIR][Arith] Add CeilFloorDivExpandOpsPatterns to conversion to LLVM (Reland) (#118839)

When running `convert-to-llvm`, `ceildiv` and `floordiv` ops, which do not
have direct llvm conversion pattern, would not get lowered to llvm
dialect. This patch adds CeilFloorDivExpandOpsPatterns to both
`convert-to-llvm` and `arith-to-llvm` (deprecated) lowering those ops to
lower level arith ops which can be lowered to llvm using LLVM
conversion.

Reland of #117305 after
buildbot failures.
See:
https://lab.llvm.org/buildbot/#/builders/80/builds/7168
https://lab.llvm.org/buildbot/#/builders/130/builds/7036
https://lab.llvm.org/buildbot/#/builders/138/builds/7290

Added dependence to ArithTransforms in ArithToLLVM. In previous
discussion, it has been suggested to move the
CeilFloorDivExpandOpsPatterns to ArithUtils but I think linking
ArithTransforms makes more sense as otherwise :
* ArithToLLVM needs a new dependency to ArithUtils
* ArithUtils needs new dependency to ArithTransforms or move the
patterns as well which will create more dependencies
* It creates lots of code motion which makes it hard to review.

Author: nujaa

mlir/lib/Conversion/ArithToLLVM/ArithToLLVM.cpp

@@ -13,6 +13,7 @@
 #include "mlir/Conversion/LLVMCommon/ConversionTarget.h"
 #include "mlir/Conversion/LLVMCommon/VectorPattern.h"
 #include "mlir/Dialect/Arith/IR/Arith.h"
+#include "mlir/Dialect/Arith/Transforms/Passes.h"
 #include "mlir/Dialect/LLVMIR/LLVMAttrs.h"
 #include "mlir/Dialect/LLVMIR/LLVMDialect.h"
 #include "mlir/IR/TypeUtilities.h"
@@ -477,7 +478,8 @@ struct ArithToLLVMConversionPass
       options.overrideIndexBitwidth(indexBitwidth);
 
     LLVMTypeConverter converter(&getContext(), options);
-    mlir::arith::populateArithToLLVMConversionPatterns(converter, patterns);
+    arith::populateCeilFloorDivExpandOpsPatterns(patterns);
+    arith::populateArithToLLVMConversionPatterns(converter, patterns);
 
     if (failed(applyPartialConversion(getOperation(), target,
                                       std::move(patterns))))
@@ -503,6 +505,7 @@ struct ArithToLLVMDialectInterface : public ConvertToLLVMPatternInterface {
   void populateConvertToLLVMConversionPatterns(
       ConversionTarget &target, LLVMTypeConverter &typeConverter,
       RewritePatternSet &patterns) const final {
+    arith::populateCeilFloorDivExpandOpsPatterns(patterns);
     arith::populateArithToLLVMConversionPatterns(typeConverter, patterns);
   }
 };

mlir/lib/Conversion/ArithToLLVM/CMakeLists.txt

@@ -13,6 +13,7 @@ add_mlir_conversion_library(MLIRArithToLLVM
   LINK_LIBS PUBLIC
   MLIRArithAttrToLLVMConversion
   MLIRArithDialect
+  MLIRArithTransforms
   MLIRLLVMCommonConversion
   MLIRLLVMDialect
   )

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

@@ -540,6 +540,68 @@ func.func @select(%arg0 : i1, %arg1 : i32, %arg2 : i32) -> i32 {
 
 // -----
 
+// CHECK-LABEL: @ceildivsi
+// CHECK-SAME: %[[ARG0:.*]]: i64) -> i64
+func.func @ceildivsi(%arg0 : i64) -> i64 {
+  // CHECK: %[[CST0:.*]] = llvm.mlir.constant(1 : i64) : i64
+  // CHECK: %[[CST1:.*]] = llvm.mlir.constant(0 : i64) : i64
+  // CHECK: %[[CST2:.*]] = llvm.mlir.constant(-1 : i64) : i64
+  // CHECK: %[[CMP0:.*]] = llvm.icmp "sgt" %[[ARG0]], %[[CST1]] : i64
+  // CHECK: %[[SEL0:.*]] = llvm.select %[[CMP0]], %[[CST2]], %[[CST0]] : i1, i64
+  // CHECK: %[[ADD0:.*]] = llvm.add %[[SEL0]], %[[ARG0]] : i64
+  // CHECK: %[[DIV0:.*]] = llvm.sdiv %[[ADD0]], %[[ARG0]] : i64
+  // CHECK: %[[ADD1:.*]] = llvm.add %[[DIV0]], %[[CST0]] : i64
+  // CHECK: %[[SUB0:.*]] = llvm.sub %[[CST1]], %[[ARG0]] : i64
+  // CHECK: %[[DIV1:.*]] = llvm.sdiv %[[SUB0]], %[[ARG0]] : i64
+  // CHECK: %[[SUB1:.*]] = llvm.sub %[[CST1]], %[[DIV1]] : i64
+  // CHECK: %[[CMP1:.*]] = llvm.icmp "slt" %[[ARG0]], %[[CST1]] : i64
+  // CHECK: %[[CMP2:.*]] = llvm.icmp "sgt" %[[ARG0]], %[[CST1]] : i64
+  // CHECK: %[[CMP3:.*]] = llvm.icmp "slt" %[[ARG0]], %[[CST1]] : i64
+  // CHECK: %[[CMP4:.*]] = llvm.icmp "sgt" %[[ARG0]], %[[CST1]] : i64
+  // CHECK: %[[AND0:.*]] = llvm.and %[[CMP1]], %[[CMP3]] : i1
+  // CHECK: %[[AND1:.*]] = llvm.and %[[CMP2]], %[[CMP4]] : i1
+  // CHECK: %[[OR:.*]] = llvm.or %[[AND0]], %[[AND1]] : i1
+  // CHECK: %[[SEL1:.*]] = llvm.select %[[OR]], %[[ADD1]], %[[SUB1]] : i1, i64
+  %0 = arith.ceildivsi %arg0, %arg0 : i64
+  return %0: i64
+}
+
+// CHECK-LABEL: @ceildivui
+// CHECK-SAME: %[[ARG0:.*]]: i32) -> i32
+func.func @ceildivui(%arg0 : i32) -> i32 {
+// CHECK: %[[CST0:.*]] = llvm.mlir.constant(0 : i32) : i32
+// CHECK: %[[CMP0:.*]] = llvm.icmp "eq" %[[ARG0]], %[[CST0]] : i32
+// CHECK: %[[CST1:.*]] = llvm.mlir.constant(1 : i32) : i32
+// CHECK: %[[SUB0:.*]] = llvm.sub %[[ARG0]], %[[CST1]] : i32
+// CHECK: %[[DIV0:.*]] = llvm.udiv %[[SUB0]], %[[ARG0]] : i32
+// CHECK: %[[ADD0:.*]] = llvm.add %[[DIV0]], %[[CST1]] : i32
+// CHECK: %[[SEL0:.*]] = llvm.select %[[CMP0]], %[[CST0]], %[[ADD0]] : i1, i32
+  %0 = arith.ceildivui %arg0, %arg0 : i32
+  return %0: i32
+}
+
+// -----
+
+// CHECK-LABEL: @floordivsi
+// CHECK-SAME: %[[ARG0:.*]]: i32, %[[ARG1:.*]]: i32) -> i32
+func.func @floordivsi(%arg0 : i32, %arg1 : i32) -> i32 {
+  // CHECK: %[[SDIV:.*]] = llvm.sdiv %[[ARG0]], %[[ARG1]] : i32
+  // CHECK: %[[MUL0:.*]] = llvm.mul %[[SDIV]], %[[ARG1]] : i32
+  // CHECK: %[[CMP0:.*]] = llvm.icmp "ne" %[[ARG0]], %[[MUL0]] : i32
+  // CHECK: %[[CST0:.*]] = llvm.mlir.constant(0 : i32) : i32
+  // CHECK: %[[CMP1:.*]] = llvm.icmp "slt" %[[ARG0]], %[[CST0]] : i32
+  // CHECK: %[[CMP2:.*]] = llvm.icmp "slt" %[[ARG1]], %[[CST0]] : i32
+  // CHECK: %[[CMP3:.*]] = llvm.icmp "ne" %[[CMP1]], %[[CMP2]] : i1
+  // CHECK: %[[AND:.*]] = llvm.and %[[CMP0]], %[[CMP3]] : i1
+  // CHECK: %[[CST1:.*]] = llvm.mlir.constant(-1 : i32) : i32
+  // CHECK: %[[ADD:.*]] = llvm.add %[[SDIV]], %[[CST1]] : i32
+  // CHECK: %[[SEL:.*]] = llvm.select %[[AND]], %[[ADD]], %[[SDIV]] : i1, i32
+  %0 = arith.floordivsi %arg0, %arg1 : i32
+  return %0 : i32
+}
+
+// -----
+
 // CHECK-LABEL: @minmaxi
 func.func @minmaxi(%arg0 : i32, %arg1 : i32) -> i32 {
   // CHECK: = llvm.intr.smin(%arg0, %arg1) : (i32, i32) -> i32