6502/llvm-6502
1
0
Fork 0
mirror of https://github.com/c64scene-ar/llvm-6502.git synced 2025-07-24 22:24:54 +00:00
Code Issues Projects Releases Wiki Activity

InstCombine: Also turn selects fed by an and into arithmetic when the types don't match.

Browse Source 
Inserting a zext or trunc is sufficient. This pattern is somewhat common in
LLVM's pointer mangling code.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@185270 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Benjamin Kramer
2013-06-29 21:17:04 +00:00
parent 97daabf318
commit edac9151fd
2 changed files with 45 additions and 4 deletions
Download Patch File Download Diff File Expand all files Collapse all files

13
lib/Transforms/InstCombine/InstCombineSelect.cpp
View File

@@ -662,7 +662,7 @@ static Value *foldSelectICmpAnd(const SelectInst &SI, ConstantInt *TrueVal,
ConstantInt *FalseVal,
InstCombiner::BuilderTy *Builder) {
const ICmpInst *IC = dyn_cast<ICmpInst>(SI.getCondition());
if (!IC || !IC->isEquality())
if (!IC || !IC->isEquality() || !SI.getType()->isIntegerTy())
return 0;
if (!match(IC->getOperand(1), m_Zero()))
@@ -670,8 +670,7 @@ static Value *foldSelectICmpAnd(const SelectInst &SI, ConstantInt *TrueVal,
ConstantInt *AndRHS;
Value *LHS = IC->getOperand(0);
if (LHS->getType() != SI.getType() ||
!match(LHS, m_And(m_Value(), m_ConstantInt(AndRHS))))
if (!match(LHS, m_And(m_Value(), m_ConstantInt(AndRHS))))
return 0;
// If both select arms are non-zero see if we have a select of the form
@@ -705,7 +704,13 @@ static Value *foldSelectICmpAnd(const SelectInst &SI, ConstantInt *TrueVal,
unsigned ValZeros = ValC->getValue().logBase2();
unsigned AndZeros = AndRHS->getValue().logBase2();
Value *V = LHS;
// If types don't match we can still convert the select by introducing a zext
// or a trunc of the 'and'. The trunc case requires that all of the truncated
// bits are zero, we can figure that out by looking at the 'and' mask.
if (AndZeros >= ValC->getBitWidth())
return 0;
Value *V = Builder->CreateZExtOrTrunc(LHS, SI.getType());
if (ValZeros > AndZeros)
V = Builder->CreateShl(V, ValZeros - AndZeros);
else if (ValZeros < AndZeros)