Make ConstantOp::getAsmResultNames() handle signfull constants

[frej]

Summary

Since IntegerAttr::getInt() was updated in
35b685270b410f6a1351c2a527021f22330c25b9 to only apply to signless
integers, trying to round trip an explicitly signed/unsigned constant
through mlir-opt has triggered an assert when
ConstantOp::getAsmResultNames() calls IntegerAttr::getInt().

This patch extends ConstantOp::getAsmResultNames() to deal with
signfull integers.

[antiagainst]

LGTM. Thanks for the fix!

[rriddle]

Thanks for the patch! Unfortunately ATM, the standard dialect does not intend to support non-signless integers. https://mlir.llvm.org/docs/Rationale/#integer-signedness-semantics

[frej]

Superseded by D76493

mlir/lib/Dialect/StandardOps/IR/Ops.cpp

if (auto intCst = getValue().dyn_cast<IntegerAttr>()) {
 
     // Sugar i1 constants with 'true' and 'false'.
     if (intTy && intTy.getWidth() == 1)
       return setNameFn(getResult(), (intCst.getInt() ? "true" : "false"));
 
     // Otherwise, build a complex name with the value and type.
     SmallString<32> specialNameBuffer;
     llvm::raw_svector_ostream specialName(specialNameBuffer);
-    specialName << 'c' << intCst.getInt();
+    specialName << 'c';
+    if (intTy && intTy.isSigned())
+      specialName << intCst.getSInt();
+    else if (intTy && intTy.isUnsigned())
+      specialName << intCst.getUInt();
+    else
+      specialName << intCst.getInt();
+
     if (intTy)
       specialName << '_' << type;
     setNameFn(getResult(), specialName.str());
 
   } else if (type.isa<FunctionType>()) {
     setNameFn(getResult(), "f");
   } else {
     setNameFn(getResult(), "cst");

mlir/test/IR/core-ops.mlir

^bb42(%t: tensor<4x4x?xf32>, %f: f32, %i: i32, %idx : index, %j: i64, %half: f16):
   %7 = constant 42 : i32
 
   // CHECK: %c43 = constant {crazy = "std.foo"} 43 : index
   %8 = constant {crazy = "std.foo"} 43: index
 
   // CHECK: %cst = constant 4.300000e+01 : bf16
   %9 = constant 43.0 : bf16
 
+  // CHECK: %c42_si32 = constant 42 : si32
+  %c42_si32 = constant 42 : si32
+
+  // CHECK: %c42_ui32 = constant 42 : ui32
+  %c42_ui32 = constant 42 : ui32
+
   // CHECK: %f = constant @func_with_ops : (f32) -> ()
   %10 = constant @func_with_ops : (f32) -> ()
 
   // CHECK: %f_1 = constant @affine_apply : () -> ()
   %11 = constant @affine_apply : () -> ()
 
   // CHECK: %f_2 = constant @affine_apply : () -> ()
   %12 = constant @affine_apply : () -> ()