[llvm-branch-commits] [llvm] [DAGCombiner][GlobalISel] Extend allMulUsesCanBeContracted with FNEG pattern (PR #188115)

[Matt Arsenault via llvm-branch-commits]

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@@ -17695,6 +17696,16 @@ static bool allMulUsesCanBeContracted(SDValue Mul) {
     if (Opcode == ISD::FADD || Opcode == ISD::FSUB)
       continue;
 
+    // FNEG use - contractable if all users of the fneg are FSUB.
+    if (Opcode == ISD::FNEG) {
+      for (const auto *FNegUser : User->users()) {
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arsenm wrote:

Can this be reduced to a 1 or 2 user scan? Unrestricted user scan can be bad for compile time in degenerate cases 

https://github.com/llvm/llvm-project/pull/188115