[llvm] [ConstraintElim] Support decrementing inductions with step -1. (PR #68644)

[Nikita Popov via llvm-commits]

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@@ -889,6 +889,26 @@ void State::addInfoForInductions(BasicBlock &BB) {
   else
     return;
 
+  // Handle negative steps.
+  if (StepOffset.isNegative()) {
+    // TODO: Extend to allow steps > -1.
+    if (!(-StepOffset).isOne())
+      return;
+
+    // AR may wrap.h
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nikic wrote:

.h

https://github.com/llvm/llvm-project/pull/68644