RPCSX/llvm
1
0
Fork 0
mirror of https://github.com/RPCSX/llvm.git synced 2024-11-26 21:20:37 +00:00
Code Issues Actions Packages Projects Releases Wiki Activity

simplify this code with the new m_Zero() pattern. Make sure the select only

Browse Source 
has a single use, and generalize it to not require N to be a constant.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@45250 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Chris Lattner 2007-12-20 01:56:58 +00:00
parent fe085f3fde
commit 42790486a8
1 changed files with 10 additions and 18 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

28
lib/Transforms/Scalar/InstructionCombining.cpp
View File

@ -2109,8 +2109,7 @@ Instruction *InstCombiner::visitAdd(BinaryOperator &I) {
}
// add (cast *A to intptrtype) B ->
// cast (GEP (cast *A to sbyte*) B) ->
// intptrtype
// cast (GEP (cast *A to sbyte*) B) --> intptrtype
{
CastInst *CI = dyn_cast<CastInst>(LHS);
Value *Other = RHS;
@ -2131,8 +2130,7 @@ Instruction *InstCombiner::visitAdd(BinaryOperator &I) {
}
}
// add (select X 0 (sub n A)) A ->
// select X A n
// add (select X 0 (sub n A)) A --> select X A n
{
SelectInst *SI = dyn_cast<SelectInst>(LHS);
Value *Other = RHS;
@ -2140,25 +2138,19 @@ Instruction *InstCombiner::visitAdd(BinaryOperator &I) {
SI = dyn_cast<SelectInst>(RHS);
Other = LHS;
}
if (SI) {
if (SI && SI->hasOneUse()) {
Value *TV = SI->getTrueValue();
Value *FV = SI->getFalseValue();
Value *A;
Value *A, *N;
// Can we fold the add into the argument of the select?
// We check both true and false select arguments for a matching subtract.
ConstantInt *C1, *C2;
if (match(FV, m_ConstantInt(C1)) && C1->getValue() == 0 &&
match(TV, m_Sub(m_ConstantInt(C2), m_Value(A))) &&
A == Other) {
// We managed to fold the add into the true select value.
return new SelectInst(SI->getCondition(), C2, A);
} else if (match(TV, m_ConstantInt(C1)) && C1->getValue() == 0 &&
match(FV, m_Sub(m_ConstantInt(C2), m_Value(A))) &&
A == Other) {
// We managed to fold the add into the false select value.
return new SelectInst(SI->getCondition(), A, C2);
}
if (match(FV, m_Zero()) && match(TV, m_Sub(m_Value(N), m_Value(A))) &&
A == Other) // Fold the add into the true select value.
return new SelectInst(SI->getCondition(), N, A);
if (match(TV, m_Zero()) && match(FV, m_Sub(m_Value(N), m_Value(A))) &&
A == Other) // Fold the add into the false select value.
return new SelectInst(SI->getCondition(), A, N);
}
}