Insert IMPLICIT_DEFS for undef uses in tail merging
Tail merging can convert an undef use into a normal one when creating a
common tail. Doing so can make the register live out from a block which
previously contained the undef use. To keep the liveness up-to-date,
insert IMPLICIT_DEFs in such blocks when necessary.
To enable this patch the computeLiveIns() function which used to
compute live-ins for a block and set them immediately is split into new
functions:
- computeLiveIns() just computes the live-ins in a LivePhysRegs set.
- addLiveIns() applies the live-ins to a block live-in list.
- computeAndAddLiveIns() is a convenience function combining the other
two functions and behaving like computeLiveIns() before this patch.
Based on a patch by Krzysztof Parzyszek <kparzysz@codeaurora.org>
Differential Revision: https://reviews.llvm.org/D37034
llvm-svn: 312668
diff --git a/llvm/lib/Target/ARM/ARMExpandPseudoInsts.cpp b/llvm/lib/Target/ARM/ARMExpandPseudoInsts.cpp
index 229346f..be7afae 100644
--- a/llvm/lib/Target/ARM/ARMExpandPseudoInsts.cpp
+++ b/llvm/lib/Target/ARM/ARMExpandPseudoInsts.cpp
@@ -860,16 +860,15 @@
MI.eraseFromParent();
// Recompute livein lists.
- const MachineRegisterInfo &MRI = MBB.getParent()->getRegInfo();
LivePhysRegs LiveRegs;
- computeLiveIns(LiveRegs, MRI, *DoneBB);
- computeLiveIns(LiveRegs, MRI, *StoreBB);
- computeLiveIns(LiveRegs, MRI, *LoadCmpBB);
+ computeAndAddLiveIns(LiveRegs, *DoneBB);
+ computeAndAddLiveIns(LiveRegs, *StoreBB);
+ computeAndAddLiveIns(LiveRegs, *LoadCmpBB);
// Do an extra pass around the loop to get loop carried registers right.
StoreBB->clearLiveIns();
- computeLiveIns(LiveRegs, MRI, *StoreBB);
+ computeAndAddLiveIns(LiveRegs, *StoreBB);
LoadCmpBB->clearLiveIns();
- computeLiveIns(LiveRegs, MRI, *LoadCmpBB);
+ computeAndAddLiveIns(LiveRegs, *LoadCmpBB);
return true;
}
@@ -980,16 +979,15 @@
MI.eraseFromParent();
// Recompute livein lists.
- const MachineRegisterInfo &MRI = MBB.getParent()->getRegInfo();
LivePhysRegs LiveRegs;
- computeLiveIns(LiveRegs, MRI, *DoneBB);
- computeLiveIns(LiveRegs, MRI, *StoreBB);
- computeLiveIns(LiveRegs, MRI, *LoadCmpBB);
+ computeAndAddLiveIns(LiveRegs, *DoneBB);
+ computeAndAddLiveIns(LiveRegs, *StoreBB);
+ computeAndAddLiveIns(LiveRegs, *LoadCmpBB);
// Do an extra pass around the loop to get loop carried registers right.
StoreBB->clearLiveIns();
- computeLiveIns(LiveRegs, MRI, *StoreBB);
+ computeAndAddLiveIns(LiveRegs, *StoreBB);
LoadCmpBB->clearLiveIns();
- computeLiveIns(LiveRegs, MRI, *LoadCmpBB);
+ computeAndAddLiveIns(LiveRegs, *LoadCmpBB);
return true;
}