[llvm] [SelectOptimize] Enable by default; add no-PGO density heuristic; fix… (PR #200691)

[Eitan Frachtenberg via llvm-commits]

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@@ -259,7 +259,7 @@ static cl::opt<bool> DisableExpandReductions(
 
 /// Disable the select optimization pass.
 static cl::opt<bool> DisableSelectOptimize(
-    "disable-select-optimize", cl::init(true), cl::Hidden,
+    "disable-select-optimize", cl::init(false), cl::Hidden,
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eitanf wrote:

Good catch. It's probably why the CI came up with all those errors for non-x86. I'll rescope selectOptimize to avoid global pipeline changes and duplicate insertions on AArch64/RISC-V. I'll ping you again after the CI confirms the test failures are fixed.

https://github.com/llvm/llvm-project/pull/200691