diff options
Diffstat (limited to 'lib/Target/X86/X86VZeroUpper.cpp')
-rw-r--r-- | lib/Target/X86/X86VZeroUpper.cpp | 11 |
1 files changed, 10 insertions, 1 deletions
diff --git a/lib/Target/X86/X86VZeroUpper.cpp b/lib/Target/X86/X86VZeroUpper.cpp index 477f75afef..0d37a7d0e6 100644 --- a/lib/Target/X86/X86VZeroUpper.cpp +++ b/lib/Target/X86/X86VZeroUpper.cpp @@ -231,8 +231,17 @@ bool VZeroUpperInserter::processBasicBlock(MachineFunction &MF, bool BBHasCall = false; for (MachineBasicBlock::iterator I = BB.begin(); I != BB.end(); ++I) { - MachineInstr *MI = I; DebugLoc dl = I->getDebugLoc(); + MachineInstr *MI = I; + + // Don't need to check instructions added in prolog. + // In prolog, special function calls may be added for specific targets + // (e.g. on Windows, a prolog helper '_chkstk' is called when the local + // variables exceed 4K bytes on stack.) These helpers won't use/def YMM/XMM + // registers. + if (MI->getFlag(MachineInstr::FrameSetup)) + continue; + bool isControlFlow = MI->isCall() || MI->isReturn(); // Shortcut: don't need to check regular instructions in dirty state. |