[PATCH] D45673: [x86] Fix PR37100 by teaching the EFLAGS copy lowering to rewrite uses across basic blocks in the limited cases where it is very straight forward to do so.

[Michael Zolotukhin via Phabricator via llvm-commits]

mzolotukhin added inline comments.


================
Comment at: llvm/trunk/lib/Target/X86/X86FlagsCopyLowering.cpp:445-457
+      if (&TestMBB != &UseMBB && !MDT->dominates(&TestMBB, &UseMBB)) {
+        DEBUG({
+          dbgs() << "ERROR: Encountered use that is not dominated by our test "
+                    "basic block! Rewriting this would require inserting PHI "
+                    "nodes to track the flag state across the CFG.\n\nTest "
+                    "block:\n";
+          TestMBB.dump();
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Could all of this be under `DEBUG`? The fatal error we're reporting here looks like an internal compiler assert anyway.
If we put in entirely under `DEBUG`, we can avoid building dominators in Release compilers.


Repository:
  rL LLVM

https://reviews.llvm.org/D45673