[clang] [llvm] [ValueTracking] Extend computeConstantRange for add/sub, sext/zext/trunc (PR #181110)

[Mikhail Gudim via cfe-commits]

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@@ -10041,6 +10045,34 @@ static void setLimitsForBinOp(const BinaryOperator &BO, APInt &Lower,
   default:
     break;
   }
+
+  ConstantRange CR = ConstantRange::getNonEmpty(Lower, Upper);
+  bool IsDisjointOr = BO.getOpcode() == Instruction::Or &&
+                      cast<PossiblyDisjointInst>(&BO)->isDisjoint();
+  if (BO.getOpcode() == Instruction::Add ||
+      BO.getOpcode() == Instruction::Sub || IsDisjointOr) {
+    // Limit recursion depth more aggressively for binary operations.
+    unsigned NewDepth = std::max(Depth * 2, 1u);
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mgudim wrote:

I don't understand this: comment says "limit depth", but NewDepth is twice the old depth?

I think before moving forward you should try to find a solution to the compile-time issue which @nikic pointed out. I personally support making this and `isKnownNonNegative` recursive.  

BTW, do you have any perf numbers for this patch?


https://github.com/llvm/llvm-project/pull/181110