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| author | Hal Finkel <hfinkel@anl.gov> | 2013-07-11 05:55:57 +0000 |
|---|---|---|
| committer | Hal Finkel <hfinkel@anl.gov> | 2013-07-11 05:55:57 +0000 |
| commit | 743b1940846b242e1cdb50d3fc0c6e8fa8dfbf0a (patch) | |
| tree | 434157e0be71d291d6031737acb1b610b240cf8a /llvm/lib/CodeGen/RegisterScavenging.cpp | |
| parent | a3635b7b3bca60cd5c901b33bb023363c2bcd0ae (diff) | |
| download | bcm5719-llvm-743b1940846b242e1cdb50d3fc0c6e8fa8dfbf0a.tar.gz bcm5719-llvm-743b1940846b242e1cdb50d3fc0c6e8fa8dfbf0a.zip | |
RegScavenger should not exclude undef uses
When computing currently-live registers, the register scavenger excludes undef
uses. As a result, undef uses are ignored when computing the restore points of
registers spilled into the emergency slots. While the register scavenger
normally excludes from consideration, when scavenging, registers used by the
current instruction, we need to not exclude undef uses. Otherwise, we might end
up requiring more emergency spill slots than we have (in the case where the
undef use *is* the currently-spilled register).
Another bug found by llvm-stress.
llvm-svn: 186067
Diffstat (limited to 'llvm/lib/CodeGen/RegisterScavenging.cpp')
| -rw-r--r-- | llvm/lib/CodeGen/RegisterScavenging.cpp | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/llvm/lib/CodeGen/RegisterScavenging.cpp b/llvm/lib/CodeGen/RegisterScavenging.cpp index d1a945df81a..75ebdaa357f 100644 --- a/llvm/lib/CodeGen/RegisterScavenging.cpp +++ b/llvm/lib/CodeGen/RegisterScavenging.cpp @@ -368,7 +368,7 @@ unsigned RegScavenger::scavengeRegister(const TargetRegisterClass *RC, // Exclude all the registers being used by the instruction. for (unsigned i = 0, e = I->getNumOperands(); i != e; ++i) { MachineOperand &MO = I->getOperand(i); - if (MO.isReg() && MO.getReg() != 0 && + if (MO.isReg() && MO.getReg() != 0 && !(MO.isUse() && MO.isUndef()) && !TargetRegisterInfo::isVirtualRegister(MO.getReg())) Candidates.reset(MO.getReg()); } |
