From 1cab3bf0046117759cc7891eec66affbbeb5965c Mon Sep 17 00:00:00 2001
From: Simon Pilgrim <llvm-dev@redking.me.uk>
Date: Fri, 23 Oct 2020 12:32:32 +0100
Subject: [PATCH] [InstCombine] matchBSwapOrBitReverse - expose
 bswap/bitreverse matching flags.

matchBSwapOrBitReverse was hardcoded to just match bswaps - we're going to need to expose the ability to match bitreverse as well, so make this part of the function call.
---
 llvm/lib/Transforms/InstCombine/InstCombineAndOrXor.cpp | 12 ++++++++----
 llvm/lib/Transforms/InstCombine/InstCombineInternal.h   |  3 ++-
 2 files changed, 10 insertions(+), 5 deletions(-)

diff --git a/llvm/lib/Transforms/InstCombine/InstCombineAndOrXor.cpp b/llvm/lib/Transforms/InstCombine/InstCombineAndOrXor.cpp
index 13670ff..1e291fb 100644
--- a/llvm/lib/Transforms/InstCombine/InstCombineAndOrXor.cpp
+++ b/llvm/lib/Transforms/InstCombine/InstCombineAndOrXor.cpp
@@ -1985,7 +1985,9 @@ Instruction *InstCombinerImpl::visitAnd(BinaryOperator &I) {
   return nullptr;
 }
 
-Instruction *InstCombinerImpl::matchBSwapOrBitReverse(BinaryOperator &Or) {
+Instruction *InstCombinerImpl::matchBSwapOrBitReverse(BinaryOperator &Or,
+                                                      bool MatchBSwaps,
+                                                      bool MatchBitReversals) {
   assert(Or.getOpcode() == Instruction::Or && "bswap requires an 'or'");
   Value *Op0 = Or.getOperand(0), *Op1 = Or.getOperand(1);
 
@@ -2011,8 +2013,9 @@ Instruction *InstCombinerImpl::matchBSwapOrBitReverse(BinaryOperator &Or) {
   if (!OrWithOrs && !OrWithShifts && !OrWithAnds)
     return nullptr;
 
-  SmallVector<Instruction*, 4> Insts;
-  if (!recognizeBSwapOrBitReverseIdiom(&Or, true, false, Insts))
+  SmallVector<Instruction *, 4> Insts;
+  if (!recognizeBSwapOrBitReverseIdiom(&Or, MatchBSwaps, MatchBitReversals,
+                                       Insts))
     return nullptr;
   Instruction *LastInst = Insts.pop_back_val();
   LastInst->removeFromParent();
@@ -2563,7 +2566,8 @@ Instruction *InstCombinerImpl::visitOr(BinaryOperator &I) {
   if (Instruction *FoldedLogic = foldBinOpIntoSelectOrPhi(I))
     return FoldedLogic;
 
-  if (Instruction *BSwap = matchBSwapOrBitReverse(I))
+  if (Instruction *BSwap = matchBSwapOrBitReverse(I, /*MatchBSwaps*/ true,
+                                                  /*MatchBitReversals*/ false))
     return BSwap;
 
   if (Instruction *Funnel = matchFunnelShift(I, *this))
diff --git a/llvm/lib/Transforms/InstCombine/InstCombineInternal.h b/llvm/lib/Transforms/InstCombine/InstCombineInternal.h
index 69811b4..6489327 100644
--- a/llvm/lib/Transforms/InstCombine/InstCombineInternal.h
+++ b/llvm/lib/Transforms/InstCombine/InstCombineInternal.h
@@ -724,7 +724,8 @@ public:
   /// Given an 'or' instruction, check to see if it is part of a
   /// bswap/bitreverse idiom. If so, return the equivalent bswap/bitreverse
   /// intrinsic.
-  Instruction *matchBSwapOrBitReverse(BinaryOperator &Or);
+  Instruction *matchBSwapOrBitReverse(BinaryOperator &Or, bool MatchBSwaps,
+                                      bool MatchBitReversals);
 
   Instruction *SimplifyAnyMemTransfer(AnyMemTransferInst *MI);
   Instruction *SimplifyAnyMemSet(AnyMemSetInst *MI);
-- 
2.7.4