[mlir][intrange] Represent bounds of ReflectBoundsOp as si/ui (#92641)

This patch adapts the `test.reflect_bounds` test Op to use explicitly
signed and unsigned representation for signed and unsigned bounds of
`IntegerType`s.

This is mostly a cosmetic change as the internal representation of the
ranges is unchanged. However, it improves readability of tests.

Author: ubfx

mlir/test/Dialect/Arith/int-range-interface.mlir

@@ -758,7 +758,7 @@ func.func private @callee(%arg0: memref<?xindex, 4>) {
 }
 
 // CHECK-LABEL: func @test_i8_bounds
-// CHECK: test.reflect_bounds {smax = 127 : i8, smin = -128 : i8, umax = -1 : i8, umin = 0 : i8}
+// CHECK: test.reflect_bounds {smax = 127 : si8, smin = -128 : si8, umax = 255 : ui8, umin = 0 : ui8}
 func.func @test_i8_bounds() -> i8 {
   %cst1 = arith.constant 1 : i8
   %0 = test.with_bounds { umin = 0 : i8, umax = 255 : i8, smin = -128 : i8, smax = 127 : i8 } : i8

mlir/test/Dialect/Arith/int-range-opts.mlir

@@ -75,7 +75,7 @@ func.func @test() -> i1 {
 // -----
 
 // CHECK-LABEL: func @test
-// CHECK: test.reflect_bounds {smax = 24 : i8, smin = 0 : i8, umax = 24 : i8, umin = 0 : i8}
+// CHECK: test.reflect_bounds {smax = 24 : si8, smin = 0 : si8, umax = 24 : ui8, umin = 0 : ui8}
 func.func @test() -> i8 {
   %cst1 = arith.constant 1 : i8
   %i8val = test.with_bounds { umin = 0 : i8, umax = 12 : i8, smin = 0 : i8, smax = 12 : i8 } : i8
@@ -87,7 +87,7 @@ func.func @test() -> i8 {
 // -----
 
 // CHECK-LABEL: func @test
-// CHECK: test.reflect_bounds {smax = 127 : i8, smin = -128 : i8, umax = -1 : i8, umin = 0 : i8}
+// CHECK: test.reflect_bounds {smax = 127 : si8, smin = -128 : si8, umax = 255 : ui8, umin = 0 : ui8}
 func.func @test() -> i8 {
   %cst1 = arith.constant 1 : i8
   %i8val = test.with_bounds { umin = 0 : i8, umax = 127 : i8, smin = 0 : i8, smax = 127 : i8 } : i8

mlir/test/lib/Dialect/Test/TestOpDefs.cpp

@@ -706,11 +706,20 @@ void TestReflectBoundsOp::inferResultRanges(
   const ConstantIntRanges &range = argRanges[0];
   MLIRContext *ctx = getContext();
   Builder b(ctx);
-  auto intTy = getType();
-  setUminAttr(b.getIntegerAttr(intTy, range.umin()));
-  setUmaxAttr(b.getIntegerAttr(intTy, range.umax()));
-  setSminAttr(b.getIntegerAttr(intTy, range.smin()));
-  setSmaxAttr(b.getIntegerAttr(intTy, range.smax()));
+  Type sIntTy, uIntTy;
+  // For plain `IntegerType`s, we can derive the appropriate signed and unsigned
+  // Types for the Attributes.
+  if (auto intTy = llvm::dyn_cast<IntegerType>(getType())) {
+    unsigned bitwidth = intTy.getWidth();
+    sIntTy = b.getIntegerType(bitwidth, /*isSigned=*/true);
+    uIntTy = b.getIntegerType(bitwidth, /*isSigned=*/false);
+  } else
+    sIntTy = uIntTy = getType();
+
+  setUminAttr(b.getIntegerAttr(uIntTy, range.umin()));
+  setUmaxAttr(b.getIntegerAttr(uIntTy, range.umax()));
+  setSminAttr(b.getIntegerAttr(sIntTy, range.smin()));
+  setSmaxAttr(b.getIntegerAttr(sIntTy, range.smax()));
   setResultRanges(getResult(), range);
 }