Wrap MLIR addAffineForOpDomain warning with LLVM_DEBUG

[TharinduRusira]

Summary

Current warning message in method addAffineForOpDomain of mlir/lib/Analysis/AffineStructures.cpp is being printed to the stdout/stderr.
This patch redirects the warning with LLVM_DEBUG following standard llvm practice.

[TharinduRusira]

First patch had changes made to an unrelated file. This update cleans the original submission.

[bondhugula]

Your patch has no context? Did you use arc diff? Please also update the commit title and summary to reflect which part of codebase/method/library this is about. For eg.

Wrap MLIR addAffineForOpDomain warning with LLVM_DEBUG

[TharinduRusira]

Updating previously submitted patch with arch diff

[TharinduRusira]

Applied the changes on a git pull so that this version of the revision is compatible with the latest LLVM HEAD.

[TharinduRusira]

I don't have commit access. Could someone commit this patch?

mlir/lib/Analysis/AffineStructures.cpp

 //===- AffineStructures.cpp - MLIR Affine Structures Class-----------------===//
 //
 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
 // See https://llvm.org/LICENSE.txt for license information.
 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 //
 //===----------------------------------------------------------------------===//
 //
FlatAffineValueConstraints::addAffineForOpDomain(AffineForOp forOp) {
   if (!findId(forOp.getInductionVar(), &pos)) {
     assert(false && "Value not found");
     return failure();
   }
 
   int64_t step = forOp.getStep();
   if (step != 1) {
     if (!forOp.hasConstantLowerBound())
-      forOp.emitWarning("domain conservatively approximated");
+      LLVM_DEBUG(forOp.emitWarning("domain conservatively approximated"));
     else {
       // Add constraints for the stride.
       // (iv - lb) % step = 0 can be written as:
       // (iv - lb) - step * q = 0 where q = (iv - lb) / step.
       // Add local variable 'q' and add the above equality.
       // The first constraint is q = (iv - lb) floordiv step
       SmallVector<int64_t, 8> dividend(getNumCols(), 0);
       int64_t lb = forOp.getConstantLowerBound();