[SimplifyCFG] Avoid redundant calls in gather. (NFC) #154133
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@llvm/pr-subscribers-llvm-transforms Author: Andreas Jonson (andjo403) ChangesSplit out from #154007 as it showed compile time improvements Full diff: https://github.com/llvm/llvm-project/pull/154133.diff 1 Files Affected:
diff --git a/llvm/lib/Transforms/Utils/SimplifyCFG.cpp b/llvm/lib/Transforms/Utils/SimplifyCFG.cpp
index 0ca7188470d8e..055e8cadaab76 100644
--- a/llvm/lib/Transforms/Utils/SimplifyCFG.cpp
+++ b/llvm/lib/Transforms/Utils/SimplifyCFG.cpp
@@ -565,6 +565,9 @@ struct ConstantComparesGatherer {
/// Number of comparisons matched in the and/or chain
unsigned UsedICmps = 0;
+ /// If the elements in Vals matches the comparisons
+ bool IsEq = false;
+
/// Construct and compute the result for the comparison instruction Cond
ConstantComparesGatherer(Instruction *Cond, const DataLayout &DL) : DL(DL) {
gather(Cond);
@@ -736,23 +739,23 @@ struct ConstantComparesGatherer {
/// vector.
/// One "Extra" case is allowed to differ from the other.
void gather(Value *V) {
- bool isEQ = match(V, m_LogicalOr(m_Value(), m_Value()));
-
+ Value *Op0, *Op1;
+ if (match(V, m_LogicalOr(m_Value(Op0), m_Value(Op1))))
+ IsEq = true;
+ else if (match(V, m_LogicalAnd(m_Value(Op0), m_Value(Op1))))
+ IsEq = false;
+ else
+ return;
// Keep a stack (SmallVector for efficiency) for depth-first traversal
- SmallVector<Value *, 8> DFT;
- SmallPtrSet<Value *, 8> Visited;
-
- // Initialize
- Visited.insert(V);
- DFT.push_back(V);
+ SmallVector<Value *, 8> DFT{Op0, Op1};
+ SmallPtrSet<Value *, 8> Visited{V, Op0, Op1};
while (!DFT.empty()) {
V = DFT.pop_back_val();
if (Instruction *I = dyn_cast<Instruction>(V)) {
// If it is a || (or && depending on isEQ), process the operands.
- Value *Op0, *Op1;
- if (isEQ ? match(I, m_LogicalOr(m_Value(Op0), m_Value(Op1)))
+ if (IsEq ? match(I, m_LogicalOr(m_Value(Op0), m_Value(Op1)))
: match(I, m_LogicalAnd(m_Value(Op0), m_Value(Op1)))) {
if (Visited.insert(Op1).second)
DFT.push_back(Op1);
@@ -763,7 +766,7 @@ struct ConstantComparesGatherer {
}
// Try to match the current instruction
- if (matchInstruction(I, isEQ))
+ if (matchInstruction(I, IsEq))
// Match succeed, continue the loop
continue;
}
@@ -5103,6 +5106,7 @@ bool SimplifyCFGOpt::simplifyBranchOnICmpChain(BranchInst *BI,
Value *CompVal = ConstantCompare.CompValue;
unsigned UsedICmps = ConstantCompare.UsedICmps;
Value *ExtraCase = ConstantCompare.Extra;
+ bool TrueWhenEqual = ConstantCompare.IsEq;
// If we didn't have a multiply compared value, fail.
if (!CompVal)
@@ -5112,8 +5116,6 @@ bool SimplifyCFGOpt::simplifyBranchOnICmpChain(BranchInst *BI,
if (UsedICmps <= 1)
return false;
- bool TrueWhenEqual = match(Cond, m_LogicalOr(m_Value(), m_Value()));
-
// There might be duplicate constants in the list, which the switch
// instruction can't handle, remove them now.
array_pod_sort(Values.begin(), Values.end(), constantIntSortPredicate);
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Overall Compile-time impact: -0.17% |
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LLVM Buildbot has detected a new failure on builder Full details are available at: https://lab.llvm.org/buildbot/#/builders/10/builds/11639 Here is the relevant piece of the build log for the reference |
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Split out from #154007 as it showed compile time improvements
NFC as there needs to be at least two icmps that is part of the chain.