[mlir] Avoid crash of UnsignedWhenEquivalent for no integer type.

[jacquesguan]

Summary

Fixes https://github.com/llvm/llvm-project/issues/59617.

[mehdi_amini]

mlir/lib/Dialect/Arith/Transforms/UnsignedWhenEquivalent.cpp

38

Where is the 0 bit width coming from?

[jacquesguan]

mlir/lib/Dialect/Arith/Transforms/UnsignedWhenEquivalent.cpp

38

IntegerValueRange IntegerValueRange::getMaxRange(Value value) {
  unsigned width = ConstantIntRanges::getStorageBitwidth(value.getType());
  APInt umin = APInt::getMinValue(width);
  APInt umax = APInt::getMaxValue(width);
  APInt smin = width != 0 ? APInt::getSignedMinValue(width) : umin;
  APInt smax = width != 0 ? APInt::getSignedMaxValue(width) : umax;
  return IntegerValueRange{ConstantIntRanges{umin, umax, smin, smax}};
}

When the type is not Integer or Index, width is 0.

[Mogball]

mlir/lib/Dialect/Arith/Transforms/UnsignedWhenEquivalent.cpp

38

The result should be set to some invalid state if the operation result type is not integral

[jacquesguan]

Address comment.

[jacquesguan]

remove unused comment.

[jacquesguan]

mlir/lib/Dialect/Arith/Transforms/UnsignedWhenEquivalent.cpp

38

Done.

mlir/lib/Dialect/Arith/Transforms/UnsignedWhenEquivalent.cpp

 /// Succeeds when a value is statically non-negative in that it has a lower
 /// bound on its value (if it is treated as signed) and that bound is
 /// non-negative.
 static LogicalResult staticallyNonNegative(DataFlowSolver &solver, Value v) {
   auto *result = solver.lookupState<IntegerValueRangeLattice>(v);
   if (!result || result->getValue().isUninitialized())
     return failure();
   const ConstantIntRanges &range = result->getValue().getValue();
-  return success(range.smin().isNonNegative());
+  // Make sure we do have the integer range analysis result.
+  return success(range.smin().getBitWidth() != 0 &&
+                 range.smin().isNonNegative());
 }
 
 /// Succeeds if an op can be converted to its unsigned equivalent without
 /// changing its semantics. This is the case when none of its openands or
 /// results can be below 0 when analyzed from a signed perspective.
 static LogicalResult staticallyNonNegative(DataFlowSolver &solver,
                                            Operation *op) {
   auto nonNegativePred = [&solver](Value v) -> bool {

mlir/test/Dialect/Arith/unsigned-when-equivalent.mlir

 
 // CHECK-LABEL: @dead_code
 func.func @dead_code() {
   %0 = call @external() : () -> i8
   // CHECK: arith.floordivsi
   %1 = arith.floordivsi %0, %0 : i8
   return
 }
+
+// Make sure not crash.
+// CHECK-LABEL: @no_integer_or_index
+func.func @no_integer_or_index() { 
+  // CHECK: arith.cmpi
+  %cst_0 = arith.constant dense<[0]> : vector<1xi32> 
+  %cmp = arith.cmpi slt, %cst_0, %cst_0 : vector<1xi32> 
+  return
+}