replica
/
hanchenye-llvm-project
2
0
Fork 0
Code Issues Pull Requests Projects Releases Wiki Activity

MCExpr: Avoid UB by evaluating this shift as unsigned 

We hit undefined behaviour in some MCExpr tests when the LHS of a left
shift is -1. Twos-complement semantics are completely reasonable here,
so we should just do the shift in unsigned.

llvm-svn: 240385
This commit is contained in:
Justin Bogner 2015-06-23 07:32:55 +00:00
parent c1709d387e
commit c16021514c
1 changed files with 1 additions and 1 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
llvm/lib/MC/MCExpr.cpp
View File

@ -752,7 +752,7 @@ bool MCExpr::evaluateAsRelocatableImpl(MCValue &Res, const MCAssembler *Asm,
case MCBinaryExpr::Mul: Result = LHS * RHS; break; case MCBinaryExpr::Mul: Result = LHS * RHS; break;
case MCBinaryExpr::NE: Result = LHS != RHS; break; case MCBinaryExpr::NE: Result = LHS != RHS; break;
case MCBinaryExpr::Or: Result = LHS | RHS; break; case MCBinaryExpr::Or: Result = LHS | RHS; break;
case MCBinaryExpr::Shl: Result = LHS << RHS; break; case MCBinaryExpr::Shl: Result = uint64_t(LHS) << uint64_t(RHS); break;
case MCBinaryExpr::Sub: Result = LHS - RHS; break; case MCBinaryExpr::Sub: Result = LHS - RHS; break;
case MCBinaryExpr::Xor: Result = LHS ^ RHS; break; case MCBinaryExpr::Xor: Result = LHS ^ RHS; break;
} }