[llvm-commits] [llvm] r45250 - /llvm/trunk/lib/Transforms/Scalar/InstructionCombining.cpp
Chris Lattner
sabre at nondot.org
Wed Dec 19 17:56:58 PST 2007
Author: lattner
Date: Wed Dec 19 19:56:58 2007
New Revision: 45250
URL: http://llvm.org/viewvc/llvm-project?rev=45250&view=rev
Log:
simplify this code with the new m_Zero() pattern. Make sure the select only
has a single use, and generalize it to not require N to be a constant.
Modified:
llvm/trunk/lib/Transforms/Scalar/InstructionCombining.cpp
Modified: llvm/trunk/lib/Transforms/Scalar/InstructionCombining.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/Scalar/InstructionCombining.cpp?rev=45250&r1=45249&r2=45250&view=diff
==============================================================================
--- llvm/trunk/lib/Transforms/Scalar/InstructionCombining.cpp (original)
+++ llvm/trunk/lib/Transforms/Scalar/InstructionCombining.cpp Wed Dec 19 19:56:58 2007
@@ -2109,8 +2109,7 @@
}
// 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 @@
}
}
- // 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 @@
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);
}
}
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