RPCSX/llvm
1
0
Fork 0
mirror of https://github.com/RPCSX/llvm.git synced 2025-03-02 01:47:06 +00:00
Code Issues Actions Packages Projects Releases Wiki Activity

add an instcombine xform. This speeds up 462.libquantum from 9.78s to

Browse Source 
7.48s.  This regression is due to unforseen consequences of the cast patch.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@32209 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Chris Lattner 2006-12-05 01:26:29 +00:00
parent 67a821d9a3
commit e13ab2a9a1
1 changed files with 17 additions and 0 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

17
lib/Transforms/Scalar/InstructionCombining.cpp
View File

@ -6023,6 +6023,23 @@ Instruction *InstCombiner::visitTrunc(CastInst &CI) {
Value *V = InsertCastBefore(SrcI->getOperand(0), Ty, CI);
return new ShiftInst(Instruction::LShr, V, SrcI->getOperand(1));
}
} else { // This is a variable shr.
// Turn 'trunc (lshr X, Y) to bool' into '(X & (1 << Y)) != 0'. This is
// more LLVM instructions, but allows '1 << Y' to be hoisted if
// loop-invariant and CSE'd.
if (CI.getType() == Type::BoolTy && SrcI->hasOneUse()) {
Value *One = ConstantInt::get(SrcI->getType(), 1);
Value *V = InsertNewInstBefore(new ShiftInst(Instruction::Shl, One,
SrcI->getOperand(1),
"tmp"), CI);
V = InsertNewInstBefore(BinaryOperator::createAnd(V,
SrcI->getOperand(0),
"tmp"), CI);
Value *Zero = Constant::getNullValue(V->getType());
return BinaryOperator::createSetNE(V, Zero);
}
}
break;
}