From a93607c479092ccae41c033f8d27fe99621ddef3 Mon Sep 17 00:00:00 2001
From: David Green <david.green@arm.com>
Date: Fri, 8 Apr 2022 12:16:34 +0100
Subject: [PATCH] [AArch64] Remove always true Perfect cost check. NFC
Perfect shuffle costs are always encoded less than 4, and shouldn't
really have a cost more than 3, so it makes no sense to check it when
generating shuffles. The perfect shuffle is likely always better than a
tbl too (although that may depend on whether it is in a loop).
---
llvm/lib/Target/AArch64/AArch64ISelLowering.cpp | 5 +----
1 file changed, 1 insertion(+), 4 deletions(-)
diff --git a/llvm/lib/Target/AArch64/AArch64ISelLowering.cpp b/llvm/lib/Target/AArch64/AArch64ISelLowering.cpp
index a43dbdb3353d..65aff576ed71 100644
--- a/llvm/lib/Target/AArch64/AArch64ISelLowering.cpp
+++ b/llvm/lib/Target/AArch64/AArch64ISelLowering.cpp
@@ -10204,10 +10204,7 @@ SDValue AArch64TargetLowering::LowerVECTOR_SHUFFLE(SDValue Op,
unsigned PFTableIndex = PFIndexes[0] * 9 * 9 * 9 + PFIndexes[1] * 9 * 9 +
PFIndexes[2] * 9 + PFIndexes[3];
unsigned PFEntry = PerfectShuffleTable[PFTableIndex];
- unsigned Cost = (PFEntry >> 30);
-
- if (Cost <= 4)
- return GeneratePerfectShuffle(PFEntry, V1, V2, DAG, dl);
+ return GeneratePerfectShuffle(PFEntry, V1, V2, DAG, dl);
}
return GenerateTBL(Op, ShuffleMask, DAG);
--
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