From 68531baea926431ba4a4a94d12c99db2b444845f Mon Sep 17 00:00:00 2001 From: Benjamin Kramer Date: Mon, 20 Dec 2010 16:18:51 +0000 Subject: Teach InstCombine to merge (icmp ult (X + CA), C1) | (icmp eq X, C2) into (icmp ult (X + CA), C1 + 1) if C2 + CA == C1. InstCombine creates these so now we compile x == 23 || x == 24 || x == 25 to %x.off = add i32 %x, -23 %1 = icmp ult i32 %x.off, 3 instead of %x.off = add i32 %x, -23 %1 = icmp ult i32 %x.off, 2 %cmp3 = icmp eq i32 %x, 25 %ret2 = or i1 %1, %cmp3 llvm-svn: 122248 --- llvm/lib/Transforms/InstCombine/InstCombineAndOrXor.cpp | 11 ++++++++++- 1 file changed, 10 insertions(+), 1 deletion(-) (limited to 'llvm/lib/Transforms') diff --git a/llvm/lib/Transforms/InstCombine/InstCombineAndOrXor.cpp b/llvm/lib/Transforms/InstCombine/InstCombineAndOrXor.cpp index 41734f6ac9d..57fe870158b 100644 --- a/llvm/lib/Transforms/InstCombine/InstCombineAndOrXor.cpp +++ b/llvm/lib/Transforms/InstCombine/InstCombineAndOrXor.cpp @@ -1450,7 +1450,16 @@ Value *InstCombiner::FoldOrOfICmps(ICmpInst *LHS, ICmpInst *RHS) { return Builder->CreateICmp(LHSCC, NewOr, LHSCst); } } - + + // (icmp ult (X + CA), C1) | (icmp eq X, C2) -> (icmp ult (X + CA), C1 + 1) + // iff C2 + CA == C1. + if (LHSCC == ICmpInst::ICMP_ULT) { + ConstantInt *AddCst; + if (match(Val, m_Add(m_Specific(Val2), m_ConstantInt(AddCst)))) + if (RHSCst->getValue() + AddCst->getValue() == LHSCst->getValue()) + return Builder->CreateICmp(LHSCC, Val, AddOne(LHSCst)); + } + // From here on, we only handle: // (icmp1 A, C1) | (icmp2 A, C2) --> something simpler. if (Val != Val2) return 0; -- cgit v1.2.3