6502/llvm-6502
1
0
Fork 0
mirror of https://github.com/c64scene-ar/llvm-6502.git synced 2025-07-16 11:24:39 +00:00
Code Issues Projects Releases Wiki Activity

Revert 72493 and replace it with a more conservative fix, for now: don't

Browse Source 
rewrite the comparison if there is any implicit extension or truncation
on the induction variable. I'm planning for IVUsers to eventually take
over some of the work of this code, and for it to be generalized.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@72496 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Dan Gohman
2009-05-27 21:10:47 +00:00
parent ba2352b066
commit c2695eba57
2 changed files with 33 additions and 7 deletions
Download Patch File Download Diff File Expand all files Collapse all files

15
lib/Transforms/Scalar/LoopStrengthReduce.cpp
View File

@@ -1993,6 +1993,12 @@ ICmpInst *LoopStrengthReduce::ChangeCompareStride(Loop *L, ICmpInst *Cond,
ValidScale(!CommonExprs->isZero(), Scale, UsersToProcess))
continue;
// Avoid rewriting the compare instruction with an iv which has
// implicit extension or truncation built into it.
// TODO: This is over-conservative.
if (SE->getTypeSizeInBits(CondUse->getOffset()->getType()) != TyBits)
continue;
// If scale is negative, use swapped predicate unless it's testing
// for equality.
if (Scale < 0 && !Cond->isEquality())
@@ -2005,16 +2011,11 @@ ICmpInst *LoopStrengthReduce::ChangeCompareStride(Loop *L, ICmpInst *Cond,
ConstantInt *CI = ConstantInt::get(NewCmpIntTy, NewCmpVal);
NewCmpRHS = ConstantExpr::getIntToPtr(CI, NewCmpTy);
}
NewOffset = CondUse->getOffset();
if (CondUse->isSigned())
NewOffset = SE->getNoopOrSignExtend(CondUse->getOffset(), NewCmpTy);
else
NewOffset = SE->getNoopOrZeroExtend(CondUse->getOffset(), NewCmpTy);
NewOffset = TyBits == NewTyBits
? SE->getMulExpr(NewOffset,
? SE->getMulExpr(CondUse->getOffset(),
SE->getConstant(ConstantInt::get(CmpTy, Scale)))
: SE->getConstant(ConstantInt::get(NewCmpIntTy,
cast<SCEVConstant>(NewOffset)->getValue()
cast<SCEVConstant>(CondUse->getOffset())->getValue()
->getSExtValue()*Scale));
break;
}