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

[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.

llvm-svn: 329771
This commit is contained in:
Craig Topper 2018-04-11 01:09:10 +00:00
parent 2b3846306d
commit ee2c1dea4d
2 changed files with 23 additions and 5 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

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

@ -727,8 +727,27 @@ 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;
}

3
llvm/test/CodeGen/X86/flags-copy-lowering.mir
View File

@ -208,11 +208,10 @@ body: |
%3:gr8 = SETAr implicit $eflags
%4:gr8 = SETBr implicit $eflags
%5:gr8 = SETEr implicit $eflags
%6:gr8 = SETNEr implicit killed $eflags
SETNEm $rsp, 1, $noreg, -16, $noreg, implicit killed $eflags
MOV8mr $rsp, 1, $noreg, -16, $noreg, killed %3
MOV8mr $rsp, 1, $noreg, -16, $noreg, killed %4
MOV8mr $rsp, 1, $noreg, -16, $noreg, killed %5
MOV8mr $rsp, 1, $noreg, -16, $noreg, killed %6
; CHECK-NOT: $eflags =
; CHECK-NOT: = SET{{.*}}
; CHECK: MOV8mr {{.*}}, killed %[[A_REG]]