Be over-conservative: scan for all used virtual registers and calculate maximal stack alignment in assumption, that there will be spill of vector register.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@50167 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Target/X86/X86RegisterInfo.cpp b/lib/Target/X86/X86RegisterInfo.cpp
index 2b14f6e..0d528f7 100644
--- a/lib/Target/X86/X86RegisterInfo.cpp
+++ b/lib/Target/X86/X86RegisterInfo.cpp
@@ -1121,11 +1121,18 @@
virtual bool runOnMachineFunction(MachineFunction &MF) {
MachineFrameInfo *FFI = MF.getFrameInfo();
+ MachineRegisterInfo &RI = MF.getRegInfo();
- // Calculate and set max stack object alignment early, so we can decide
- // whether we will need stack realignment (and thus FP).
+ // Calculate max stack alignment of all already allocated stack objects.
unsigned MaxAlign = calculateMaxStackAlignment(FFI);
+ // Be over-conservative: scan over all vreg defs and find, whether vector
+ // registers are used. If yes - there is probability, that vector register
+ // will be spilled and thus stack needs to be aligned properly.
+ for (unsigned RegNum = TargetRegisterInfo::FirstVirtualRegister;
+ RegNum < RI.getLastVirtReg(); ++RegNum)
+ MaxAlign = std::max(MaxAlign, RI.getRegClass(RegNum)->getAlignment());
+
FFI->setMaxAlignment(MaxAlign);
return false;
diff --git a/lib/Target/X86/X86TargetMachine.cpp b/lib/Target/X86/X86TargetMachine.cpp
index f75a77c..218f356 100644
--- a/lib/Target/X86/X86TargetMachine.cpp
+++ b/lib/Target/X86/X86TargetMachine.cpp
@@ -162,6 +162,8 @@
}
bool X86TargetMachine::addPreRegAlloc(PassManagerBase &PM, bool Fast) {
+ // Calculate and set max stack object alignment early, so we can decide
+ // whether we will need stack realignment (and thus FP).
PM.add(createX86MaxStackAlignmentCalculatorPass());
return false; // -print-machineinstr shouldn't print after this.
}