[clang] [compiler-rt] [llvm] [InstrProf] Single byte counters in coverage (PR #75425)

[Zequan Wu via cfe-commits]

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@@ -569,16 +577,26 @@ struct CounterCoverageMappingBuilder
 
   /// Return a counter for the subtraction of \c RHS from \c LHS
   Counter subtractCounters(Counter LHS, Counter RHS, bool Simplify = true) {
+    if (llvm::EnableSingleByteCoverage)
+      assert(
+          0 &&
+          "cannot subtract counters when single byte coverage mode is enabled");
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ZequanWu wrote:

This can be simplifies to `assert(!llvm::EnableSingleByteCoverage && "cannot subtract counters when single byte coverage mode is enabled")`. Same for the following asserts.

https://github.com/llvm/llvm-project/pull/75425