[llvm] [Float2Int] Fix pessimization in the MinBW calculation. (PR #86051)

[Nikita Popov via llvm-commits]

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@@ -359,8 +359,8 @@ bool Float2IntPass::validateAndTransform() {
 
     // The number of bits required is the maximum of the upper and
     // lower limits, plus one so it can be signed.
-    unsigned MinBW = std::max(R.getLower().getSignificantBits(),
-                              R.getUpper().getSignificantBits()) +
+    unsigned MinBW = std::max(R.getSignedMin().getSignificantBits(),
+                              R.getSignedMax().getSignificantBits()) +
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nikic wrote:

Use `R.getMinSignedBits()` instead?

https://github.com/llvm/llvm-project/pull/86051