6502/llvm-6502
1
0
Fork 0
mirror of https://github.com/c64scene-ar/llvm-6502.git synced 2025-06-30 20:24:32 +00:00
Code Issues Projects Releases Wiki Activity

InstSimplify: Move a transform from InstCombine to InstSimplify

Browse Source 
Several combines involving icmp (shl C2, %X) C1 can be simplified
without introducing any new instructions.  Move them to InstSimplify;
while we are at it, make them more powerful.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@216642 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
David Majnemer
2014-08-28 03:34:28 +00:00
parent 4a76317ebb
commit b11fff1d8a
4 changed files with 105 additions and 44 deletions
Download Patch File Download Diff File Expand all files Collapse all files

10
lib/Transforms/InstCombine/InstCombineCompares.cpp
View File

@ -1503,16 +1503,10 @@ Instruction *InstCombiner::visitICmpInstWithInstAndIntCst(ICmpInst &ICI,
unsigned RHSLog2 = RHSV.logBase2();
// (1 << X) >= 2147483648 -> X >= 31 -> X == 31
// (1 << X) > 2147483648 -> X > 31 -> false
// (1 << X) <= 2147483648 -> X <= 31 -> true
// (1 << X) < 2147483648 -> X < 31 -> X != 31
if (RHSLog2 == TypeBits-1) {
if (Pred == ICmpInst::ICMP_UGE)
Pred = ICmpInst::ICMP_EQ;
else if (Pred == ICmpInst::ICMP_UGT)
return ReplaceInstUsesWith(ICI, Builder->getFalse());
else if (Pred == ICmpInst::ICMP_ULE)
return ReplaceInstUsesWith(ICI, Builder->getTrue());
else if (Pred == ICmpInst::ICMP_ULT)
Pred = ICmpInst::ICMP_NE;
}
@ -1547,10 +1541,6 @@ Instruction *InstCombiner::visitICmpInstWithInstAndIntCst(ICmpInst &ICI,
if (RHSVIsPowerOf2)
return new ICmpInst(
Pred, X, ConstantInt::get(RHS->getType(), RHSV.logBase2()));
return ReplaceInstUsesWith(
ICI, Pred == ICmpInst::ICMP_EQ ? Builder->getFalse()
: Builder->getTrue());
}
}
break;