Fix up some mixed sign warnings.

--

PiperOrigin-RevId: 246614498
diff --git a/mlir/lib/Transforms/LoopFusion.cpp b/mlir/lib/Transforms/LoopFusion.cpp
index f8db53a..fda6574 100644
--- a/mlir/lib/Transforms/LoopFusion.cpp
+++ b/mlir/lib/Transforms/LoopFusion.cpp
@@ -1676,7 +1676,7 @@
                             << "   fused mem: " << fusedMem << "\n"
                             << "   slice mem: " << sliceMemEstimate << "\n");
 
-    if (fusedMem > srcMemSizeVal + dstMemSizeVal) {
+    if (static_cast<long>(fusedMem) > srcMemSizeVal + dstMemSizeVal) {
       LLVM_DEBUG(llvm::dbgs() << "Fusion is not profitable; NOT fusing.\n");
       return false;
     }
diff --git a/mlir/lib/Transforms/Utils/GreedyPatternRewriteDriver.cpp b/mlir/lib/Transforms/Utils/GreedyPatternRewriteDriver.cpp
index 8c6a932..3fd44c7 100644
--- a/mlir/lib/Transforms/Utils/GreedyPatternRewriteDriver.cpp
+++ b/mlir/lib/Transforms/Utils/GreedyPatternRewriteDriver.cpp
@@ -53,7 +53,7 @@
 
   /// Perform the rewrites. Return true if the rewrite converges in
   /// `maxIterations`.
-  bool simplifyFunction(unsigned maxIterations);
+  bool simplifyFunction(int maxIterations);
 
   void addToWorklist(Operation *op) {
     // Check to see if the worklist already contains this op.
@@ -146,7 +146,7 @@
 }; // end anonymous namespace
 
 /// Perform the rewrites.
-bool GreedyPatternRewriteDriver::simplifyFunction(unsigned maxIterations) {
+bool GreedyPatternRewriteDriver::simplifyFunction(int maxIterations) {
   Function *fn = builder.getFunction();
   ConstantFoldHelper helper(fn);