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MC: mayAffectControlFlow() handling for variadic instructions.

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Variadic MC instructions don't note whether the variable operands
are uses or defs, so mayAffectControlFlow() must conservatively
assume they are defs and return true if the PC is in the operand
list.

rdar://14488628

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@186846 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Jim Grosbach 2013-07-22 17:45:55 +00:00
parent b987c40548
commit 741e37ed0d
1 changed files with 14 additions and 2 deletions
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16
include/llvm/MC/MCInstrDesc.h
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@ -268,8 +268,20 @@ public:
if (isBranch() || isCall() || isReturn() || isIndirectBranch())
return true;
unsigned PC = RI.getProgramCounter();
if (PC == 0) return false;
return hasDefOfPhysReg(MI, PC, RI);
if (PC == 0)
return false;
if (hasDefOfPhysReg(MI, PC, RI))
return true;
// A variadic instruction may define PC in the variable operand list.
// There's currently no indication of which entries in a variable
// list are defs and which are uses. While that's the case, this function
// needs to assume they're defs in order to be conservatively correct.
for (int i = NumOperands, e = MI.getNumOperands(); i != e; ++i) {
if (MI.getOperand(i).isReg() &&
RI.isSubRegisterEq(PC, MI.getOperand(i).getReg()))
return true;
}
return false;
}
/// \brief Return true if this instruction has a predicate operand