[llvm] [VectorCombine] foldPermuteOfBinops - support multi-use binary ops and operands in shuffle folding (PR #173153)

[Miloš Poletanović via llvm-commits]

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@@ -2340,22 +2336,35 @@ bool VectorCombine::foldPermuteOfBinops(Instruction &I) {
       all_of(NewMask1, [NumOpElts](int M) { return M < (int)NumOpElts; }) &&
       ShuffleVectorInst::isIdentityMask(NewMask1, NumOpElts);
 
+  InstructionCost NewCost = 0;
   // Try to merge shuffles across the binop if the new shuffles are not costly.
+  InstructionCost BinOpCost =
+      TTI.getArithmeticInstrCost(Opcode, BinOpTy, CostKind);
   InstructionCost OldCost =
-      TTI.getArithmeticInstrCost(Opcode, BinOpTy, CostKind) +
-      TTI.getShuffleCost(TargetTransformInfo::SK_PermuteSingleSrc, ShuffleDstTy,
-                         BinOpTy, OuterMask, CostKind, 0, nullptr, {BinOp}, &I);
-  if (Match0)
-    OldCost += TTI.getShuffleCost(
+      BinOpCost + TTI.getShuffleCost(TargetTransformInfo::SK_PermuteSingleSrc,
+                                     ShuffleDstTy, BinOpTy, OuterMask, CostKind,
+                                     0, nullptr, {BinOp}, &I);
+  if (!BinOp->hasOneUse())
+    NewCost += BinOpCost;
+
+  if (Match0) {
+    InstructionCost Shuf0Cost = TTI.getShuffleCost(
         TargetTransformInfo::SK_PermuteTwoSrc, BinOpTy, Op0Ty, Mask0, CostKind,
         0, nullptr, {Op00, Op01}, cast<Instruction>(BinOp->getOperand(0)));
-  if (Match1)
-    OldCost += TTI.getShuffleCost(
-        TargetTransformInfo::SK_PermuteTwoSrc, BinOpTy, Op1Ty, Mask1, CostKind,
+    OldCost += Shuf0Cost;
+    if (!BinOp->getOperand(0)->hasOneUse())
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milos1397 wrote:

Correct, I missed that part.

https://github.com/llvm/llvm-project/pull/173153