[PatternMatch] Make m_Br more flexible, add matchers for BB values.

Currently m_Br only takes references to BasicBlock*, which limits its
flexibility. For example, you have to declare a variable, even if you
ignore the result or you have to have additional checks to make sure the
matched BB matches an expected one.

This patch adds m_BasicBlock and m_SpecificBB matchers, which can be
used like the existing matchers for constants or values.

I also had a look at the existing uses and updated a few. IMO it makes
the code a bit more explicit.

Reviewers: spatel, craig.topper, RKSimon, majnemer, lebedev.ri

Reviewed By: lebedev.ri

Differential Revision: https://reviews.llvm.org/D68013

llvm-svn: 372885

1 files changed, 4 insertions, 5 deletions

diff --git a/llvm/lib/Transforms/AggressiveInstCombine/AggressiveInstCombine.cpp b/llvm/lib/Transforms/AggressiveInstCombine/AggressiveInstCombine.cpp
index 5e7587b2264..6e2867f5708 100644
--- a/llvm/lib/Transforms/AggressiveInstCombine/AggressiveInstCombine.cpp
+++ b/llvm/lib/Transforms/AggressiveInstCombine/AggressiveInstCombine.cpp
@@ -121,14 +121,13 @@ static bool foldGuardedRotateToFunnelShift(Instruction &I) {
   BasicBlock *GuardBB = Phi.getIncomingBlock(RotSrc == P1);
   BasicBlock *RotBB = Phi.getIncomingBlock(RotSrc != P1);
   Instruction *TermI = GuardBB->getTerminator();
-  BasicBlock *TrueBB, *FalseBB;
   ICmpInst::Predicate Pred;
-  if (!match(TermI, m_Br(m_ICmp(Pred, m_Specific(RotAmt), m_ZeroInt()), TrueBB,
-                         FalseBB)))
+  BasicBlock *PhiBB = Phi.getParent();
+  if (!match(TermI, m_Br(m_ICmp(Pred, m_Specific(RotAmt), m_ZeroInt()),
+                         m_SpecificBB(PhiBB), m_SpecificBB(RotBB))))
     return false;
 
-  BasicBlock *PhiBB = Phi.getParent();
-  if (Pred != CmpInst::ICMP_EQ || TrueBB != PhiBB || FalseBB != RotBB)
+  if (Pred != CmpInst::ICMP_EQ)
     return false;
 
   // We matched a variation of this IR pattern: