[llvm] [SLP]Improve minbitwidth analysis. (PR #78976)

[Simon Pilgrim via llvm-commits]

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@@ -13245,23 +13271,32 @@ bool BoUpSLP::collectValuesToDemote(
   case Instruction::Mul:
   case Instruction::And:
   case Instruction::Or:
-  case Instruction::Xor:
-    if (!collectValuesToDemote(I->getOperand(0), ToDemote, DemotedConsts, Roots,
-                               Visited) ||
-        !collectValuesToDemote(I->getOperand(1), ToDemote, DemotedConsts, Roots,
-                               Visited))
+  case Instruction::Xor: {
+    unsigned Level1, Level2;
+    if (!collectValuesToDemote(I->getOperand(0), IsProfitableToDemoteRoot,
+                               BitWidth, ToDemote, DemotedConsts, Visited,
+                               Level1, IsProfitableToDemote) ||
+        !collectValuesToDemote(I->getOperand(1), IsProfitableToDemoteRoot,
+                               BitWidth, ToDemote, DemotedConsts, Visited,
+                               Level2, IsProfitableToDemote))
       return false;
+    MaxDepthLevel = std::max(Level1, Level2);
     break;
+  }
 
   // We can demote selects if we can demote their true and false values.
   case Instruction::Select: {
     Start = 1;
+    unsigned Level1, Level2;
     SelectInst *SI = cast<SelectInst>(I);
-    if (!collectValuesToDemote(SI->getTrueValue(), ToDemote, DemotedConsts,
-                               Roots, Visited) ||
-        !collectValuesToDemote(SI->getFalseValue(), ToDemote, DemotedConsts,
-                               Roots, Visited))
+    if (!collectValuesToDemote(SI->getTrueValue(), IsProfitableToDemoteRoot,
+                               BitWidth, ToDemote, DemotedConsts, Visited,
+                               Level1, IsProfitableToDemote) ||
+        !collectValuesToDemote(SI->getFalseValue(), IsProfitableToDemoteRoot,
+                               BitWidth, ToDemote, DemotedConsts, Visited,
+                               Level2, IsProfitableToDemote))
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RKSimon wrote:

Can the 2 calls both try to set IsProfitableToDemote?

https://github.com/llvm/llvm-project/pull/78976