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Pull in r329771 from upstream llvm trunk (by Craig Topper):

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[X86] In X86FlagsCopyLowering, when rewriting a memory setcc we need
  to emit an explicit MOV8mr instruction.

  Previously the code only knew how to handle setcc to a register.

  This should fix a crash in the chromium build.

This fixes various assertion failures while building ports targeting
i386:
* www/firefox: isReg() && "This is not a register operand!"
* www/iridium, www/qt5-webengine: (I.atEnd() || std::next(I) ==
  def_instr_end()) && "getVRegDef assumes a single definition or no
  definition"
* devel/powerpc64-gcc: FromReg != ToReg && "Cannot replace a reg with
  itself"

Reported by:	jbeich
PR:		225330, 227686, 227698, 227699
MFC after:	1 week
X-MFC-With:	r332833
This commit is contained in:
dim 2018-04-23 23:07:57 +00:00
parent c0908e1f7b
commit de8877900a
1 changed files with 22 additions and 3 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

25
contrib/llvm/lib/Target/X86/X86FlagsCopyLowering.cpp
View File

@ -770,8 +770,27 @@ void X86FlagsCopyLoweringPass::rewriteSetCC(MachineBasicBlock &TestMBB,
if (!CondReg)
CondReg = promoteCondToReg(TestMBB, TestPos, TestLoc, Cond);
// Rewriting this is trivial: we just replace the register and remove the
// setcc.
MRI->replaceRegWith(SetCCI.getOperand(0).getReg(), CondReg);
// Rewriting a register def is trivial: we just replace the register and
// remove the setcc.
if (!SetCCI.mayStore()) {
assert(SetCCI.getOperand(0).isReg() &&
"Cannot have a non-register defined operand to SETcc!");
MRI->replaceRegWith(SetCCI.getOperand(0).getReg(), CondReg);
SetCCI.eraseFromParent();
return;
}
// Otherwise, we need to emit a store.
auto MIB = BuildMI(*SetCCI.getParent(), SetCCI.getIterator(),
SetCCI.getDebugLoc(), TII->get(X86::MOV8mr));
// Copy the address operands.
for (int i = 0; i < X86::AddrNumOperands; ++i)
MIB.add(SetCCI.getOperand(i));
MIB.addReg(CondReg);
MIB->setMemRefs(SetCCI.memoperands_begin(), SetCCI.memoperands_end());
SetCCI.eraseFromParent();
return;
}