[mlir] Create lbOperands before op.setLowerBound

[vitalybuka]

Summary

To fix msan report like https://reviews.llvm.org/P8284

[vitalybuka]

Existing tests pass but I have no idea if this is correct.

[vitalybuka]

In D124575#3478690, @vitalybuka wrote:

Existing tests pass but I have no idea if this is correct.

I double checked that content of (lb.getOperands().begin(), lb.getOperands().begin() +lb.getMap().getNumDims()) is the same before and after patch. So I believe it's correct to move like this.

[rriddle]

This looks right.

mlir/lib/Dialect/Affine/Utils/Utils.cpp

LogicalResult mlir::normalizeAffineFor(AffineForOp op) {
 
   // Construct newUbMap.
   AffineMap newUbMap =
       AffineMap::get(origLbMap.getNumDims() + origUbMap.getNumDims(),
                      origLbMap.getNumSymbols() + origUbMap.getNumSymbols(),
                      newUbExprs, opBuilder.getContext());
   canonicalizeMapAndOperands(&newUbMap, &ubOperands);
 
+  SmallVector<Value, 4> lbOperands(lb.getOperands().begin(),
+                                   lb.getOperands().begin() +
+                                       lb.getMap().getNumDims());
+
   // Normalize the loop.
   op.setUpperBound(ubOperands, newUbMap);
   op.setLowerBound({}, opBuilder.getConstantAffineMap(0));
   op.setStep(1);
 
   // Calculate the Value of new loopIV. Create affine.apply for the value of
   // the loopIV in normalized loop.
   opBuilder.setInsertionPointToStart(op.getBody());
-  SmallVector<Value, 4> lbOperands(lb.getOperands().begin(),
-                                   lb.getOperands().begin() +
-                                       lb.getMap().getNumDims());
   // Add an extra dim operand for loopIV.
   lbOperands.push_back(op.getInductionVar());
   // Add symbol operands from lower bound.
   for (unsigned j = 0, e = origLbMap.getNumSymbols(); j < e; ++j)
     lbOperands.push_back(lb.getOperand(origLbMap.getNumDims() + j));
 
   AffineExpr origIVExpr = opBuilder.getAffineDimExpr(lb.getMap().getNumDims());
   AffineExpr newIVExpr = origIVExpr * origLoopStep + origLbMap.getResult(0);