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SystemZ: Avoid left shifting negative values (it's UB)

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Found by ubsan.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@240420 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Justin Bogner 2015-06-23 15:38:24 +00:00
parent 896353d663
commit 3800e768a2
1 changed files with 4 additions and 4 deletions
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8
lib/Target/SystemZ/SystemZISelLowering.cpp
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@ -2005,17 +2005,17 @@ static Comparison getIntrinsicCmp(SelectionDAG &DAG, unsigned Opcode,
else if (Cond == ISD::SETLT || Cond == ISD::SETULT)
// bits above bit 3 for CC==0 (always false), bits above bit 0 for CC==3,
// always true for CC>3.
C.CCMask = CC < 4 ? -1 << (4 - CC) : -1;
C.CCMask = CC < 4 ? ~0U << (4 - CC) : -1;
else if (Cond == ISD::SETGE || Cond == ISD::SETUGE)
// ...and the inverse of that.
C.CCMask = CC < 4 ? ~(-1 << (4 - CC)) : 0;
C.CCMask = CC < 4 ? ~(~0U << (4 - CC)) : 0;
else if (Cond == ISD::SETLE || Cond == ISD::SETULE)
// bit 3 and above for CC==0, bit 0 and above for CC==3 (always true),
// always true for CC>3.
C.CCMask = CC < 4 ? -1 << (3 - CC) : -1;
C.CCMask = CC < 4 ? ~0U << (3 - CC) : -1;
else if (Cond == ISD::SETGT || Cond == ISD::SETUGT)
// ...and the inverse of that.
C.CCMask = CC < 4 ? ~(-1 << (3 - CC)) : 0;
C.CCMask = CC < 4 ? ~(~0U << (3 - CC)) : 0;
else
llvm_unreachable("Unexpected integer comparison type");
C.CCMask &= CCValid;