[5.10] [Profiler] Remove an assertion

Due to the recent change to how we simplify
counters (rdar://118185163), we can now end up
hitting this assertion for certain do-catch
statements. The counter has always been wrong
here, and previously would have underflowed at
runtime (rdar://100470244). This issue has been
properly fixed on main, but we haven't
cherry-picked that fix to 5.10 since it requires a
bunch of other changes. For now, just remove the
assertion to maintain the previous behavior.

rdar://118896974

Author: hamishknight

lib/SIL/IR/SILProfiler.cpp

@@ -781,7 +781,8 @@ struct CoverageMapping : public ASTWalker {
   /// Subtract \c Expr from \c Node's counter.
   void subtractFromCounter(ASTNode Node, CounterExpr Expr) {
     auto Counter = getCounter(Node);
-    assert(!Counter.isZero() && "Cannot create a negative counter");
+    // FIXME: This assertion ought to be restored (rdar://100470244)
+    // assert(!Counter.isZero() && "Cannot create a negative counter");
     assignCounter(Node,
                   CounterExpr::Sub(Counter, std::move(Expr), CounterBuilder));
   }

test/Profiler/rdar118896974.swift

@@ -0,0 +1,10 @@
+// RUN: %target-swift-frontend -profile-generate -profile-coverage-mapping -emit-ir %s
+
+// rdar://118896974 - Make sure we don't crash.
+func foo() {
+  do {
+    return
+  } catch {
+    return
+  }
+}