[MLIR][LLVM] Fix #llvm.constant_range parsing

Author: Kuree

mlir/lib/Dialect/LLVMIR/IR/LLVMAttrs.cpp

@@ -270,11 +270,9 @@ Attribute ConstantRangeAttr::parse(AsmParser &parser, Type odsType) {
   if (parser.parseInteger(lower) || parser.parseComma() ||
       parser.parseInteger(upper) || parser.parseGreater())
     return Attribute{};
-  // For some reason, 0 is always parsed as 64-bits, fix that if needed.
-  if (lower.isZero())
-    lower = lower.sextOrTrunc(bitWidth);
-  if (upper.isZero())
-    upper = upper.sextOrTrunc(bitWidth);
+  // Non-positive numbers may use more bits than `bitWidth`
+  lower = lower.sextOrTrunc(bitWidth);
+  upper = upper.sextOrTrunc(bitWidth);
   return parser.getChecked<ConstantRangeAttr>(loc, parser.getContext(), lower,
                                               upper);
 }

mlir/test/Dialect/LLVMIR/func.mlir

@@ -479,3 +479,9 @@ llvm.func @intel_reqd_sub_group_size_hint() attributes {llvm.intel_reqd_sub_grou
 // CHECK-SAME: llvm.workgroup_attribution = #llvm.mlir.workgroup_attribution<512 : i64, i32>
 // CHECK-SAME: llvm.workgroup_attribution = #llvm.mlir.workgroup_attribution<128 : i64, !llvm.struct<(i32, i64, f32)>
 llvm.func @workgroup_attribution(%arg0: !llvm.ptr {llvm.workgroup_attribution = #llvm.mlir.workgroup_attribution<512 : i64, i32>}, %arg1: !llvm.ptr {llvm.workgroup_attribution = #llvm.mlir.workgroup_attribution<128 : i64, !llvm.struct<(i32, i64, f32)>>})
+
+// -----
+
+// CHECK: @constant_range_negative
+// CHECK-SAME: llvm.range = #llvm.constant_range<i32, 0, -2147483648>
+llvm.func @constant_range_negative() -> (i32 {llvm.range = #llvm.constant_range<i32, 0, -2147483648>})