[mlir] Don't inline calls from dead SCCs

[ftynse]

Summary

During iterative inlining of the functions in a multi-step call chain, the
inliner could add the same call operation several times to the worklist, which
led to use-after-free when this op was considered more than once.

Closes #52887.

[ftynse]

git add

[wsmoses]

mlir/lib/Transforms/Inliner.cpp

461

Could this be changed to a set vector to avoid an O(N) check on this line?

[wsmoses]

LGTM with a change to setvector.

[ftynse]

Use SmallSetVector.

mlir/lib/Transforms/Inliner.cpp

if (useList.isDead(node)) {
                      calls, /*traverseNestedCGNodes=*/false);
     }
   }
 
   // Try to inline each of the call operations. Don't cache the end iterator
   // here as more calls may be added during inlining.
   bool inlinedAnyCalls = false;
   for (unsigned i = 0; i != calls.size(); ++i) {
+    if (llvm::find(deadNodes, calls[i].sourceNode) != deadNodes.end())
+      continue;
     ResolvedCall it = calls[i];
     bool doInline = shouldInline(it);
     CallOpInterface call = it.call;
     LLVM_DEBUG({
       if (doInline)
         llvm::dbgs() << "* Inlining call: " << call << "\n";
       else
         llvm::dbgs() << "* Not inlining call: " << call << "\n";

mlir/test/Transforms/inlining-repeated-use.mlir

+// RUN: mlir-opt -inline %s | FileCheck %s
+
+// This could crash the inliner, make sure it does not.
+
+func @A() {
+  call @B() { inA } : () -> ()
+  return
+}
+
+func @B() {
+  call @E() : () -> ()
+  return
+}
+
+func @C() {
+  call @D() : () -> ()
+  return
+}
+
+func private @D() {
+  call @B() { inD } : () -> ()
+  return
+}
+
+func @E() {
+  call @fabsf() : () -> ()
+  return
+}
+
+func private @fabsf()
+
+// CHECK: func @A() {
+// CHECK:   call @fabsf() : () -> ()
+// CHECK:   return
+// CHECK: }
+// CHECK: func @B() {
+// CHECK:   call @fabsf() : () -> ()
+// CHECK:   return
+// CHECK: }
+// CHECK: func @C() {
+// CHECK:   call @fabsf() : () -> ()
+// CHECK:   return
+// CHECK: }
+// CHECK: func @E() {
+// CHECK:   call @fabsf() : () -> ()
+// CHECK:   return
+// CHECK: }
+// CHECK: func private @fabsf()