Accept null PhysReg arguments to checkRegMaskInterference.

Calling checkRegMaskInterference(VirtReg) checks if VirtReg crosses any
regmask operands, regardless of the registers they clobber.

llvm-svn: 158563

2 files changed, 3 insertions, 2 deletions

diff --git a/llvm/lib/CodeGen/LiveRegMatrix.cpp b/llvm/lib/CodeGen/LiveRegMatrix.cpp
index 61e1432b0e2..cdb17768129 100644
--- a/llvm/lib/CodeGen/LiveRegMatrix.cpp
+++ b/llvm/lib/CodeGen/LiveRegMatrix.cpp
@@ -110,7 +110,7 @@ bool LiveRegMatrix::checkRegMaskInterference(LiveInterval &VirtReg,
   // The BitVector is indexed by PhysReg, not register unit.
   // Regmask interference is more fine grained than regunits.
   // For example, a Win64 call can clobber %ymm8 yet preserve %xmm8.
-  return !RegMaskUsable.empty() && !RegMaskUsable.test(PhysReg);
+  return !RegMaskUsable.empty() && (!PhysReg || !RegMaskUsable.test(PhysReg));
 }
 
 bool LiveRegMatrix::checkRegUnitInterference(LiveInterval &VirtReg,
diff --git a/llvm/lib/CodeGen/LiveRegMatrix.h b/llvm/lib/CodeGen/LiveRegMatrix.h
index 4c3e7d47821..019a5f5877e 100644
--- a/llvm/lib/CodeGen/LiveRegMatrix.h
+++ b/llvm/lib/CodeGen/LiveRegMatrix.h
@@ -124,7 +124,8 @@ public:
 
   /// Check for regmask interference only.
   /// Return true if VirtReg crosses a regmask operand that clobbers PhysReg.
-  bool checkRegMaskInterference(LiveInterval &VirtReg, unsigned PhysReg);
+  /// If PhysReg is null, check if VirtReg crosses any regmask operands.
+  bool checkRegMaskInterference(LiveInterval &VirtReg, unsigned PhysReg = 0);
 
   /// Check for regunit interference only.
   /// Return true if VirtReg overlaps a fixed assignment of one of PhysRegs's