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[InstCombine] remove duplicated fold ; NFCI 

This pattern is matched in foldICmpBinOpEqualityWithConstant() and already works
with vectors too. I changed some comments over there to point out the current 
location. The tests for this transform are currently in 'sub.ll'.

Note that the remaining folds in this block all require a sub too, so they should
get grouped with the other icmp(sub) patterns.

llvm-svn: 281627
This commit is contained in:
Sanjay Patel 2016-09-15 17:01:17 +00:00
parent b2d62bd071
commit 362ff5c0a5
1 changed files with 2 additions and 7 deletions
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9
llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp
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@ -1423,11 +1423,6 @@ Instruction *InstCombiner::foldICmpWithConstant(ICmpInst &Cmp) {
// The following transforms are only worth it if the only user of the subtract
// is the icmp.
if (X->hasOneUse()) {
// (icmp ne/eq (sub A B) 0) -> (icmp ne/eq A, B)
if (Cmp.isEquality() && CI->isZero() &&
match(X, m_Sub(m_Value(A), m_Value(B))))
return new ICmpInst(Pred, A, B);
// (icmp sgt (sub nsw A B), -1) -> (icmp sge A, B)
if (Pred == ICmpInst::ICMP_SGT && CI->isAllOnesValue() &&
match(X, m_NSWSub(m_Value(A), m_Value(B))))
@ -2522,11 +2517,11 @@ Instruction *InstCombiner::foldICmpBinOpEqualityWithConstant(ICmpInst &Cmp,
if (BO->hasOneUse()) {
const APInt *BOC;
if (match(BOp0, m_APInt(BOC))) {
// Replace ((sub A, B) != C) with (B != A-C) if A & C are constants.
// Replace ((sub BOC, B) != C) with (B != BOC-C).
Constant *SubC = ConstantExpr::getSub(cast<Constant>(BOp0), RHS);
return new ICmpInst(Pred, BOp1, SubC);
} else if (*C == 0) {
// Replace ((sub A, B) != 0) with (A != B)
// Replace ((sub A, B) != 0) with (A != B).
return new ICmpInst(Pred, BOp0, BOp1);
}
}