[llvm] [DAGCombiner] Option --combiner-select-seq (PR #134813)

[Matt Arsenault via llvm-commits]

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@@ -149,6 +149,18 @@ static cl::opt<bool> EnableShrinkLoadReplaceStoreWithStore(
     cl::desc("DAG combiner enable load/<replace bytes>/store with "
              "a narrower store"));
 
+static cl::opt<bool> SelectSeq(
+    "combiner-select-seq", cl::Hidden, cl::init(false),
+    cl::desc("DAG combiner minimize condition-code lifetime for select "
+             "sequences over constants in arithmetic progressions"),
+    cl::ZeroOrMore);
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arsenm wrote:

These are the kind of flags that will not be used, can you just do this unconditionally or based on some existing set of target preference hooks? e.g. hasMultipleConditionRegisters, shouldNormalizeToSelectSequence 

https://github.com/llvm/llvm-project/pull/134813