2 files changed, 17 insertions, 3 deletions

diff --git a/contrib/llvm-project/llvm/lib/Target/SystemZ/SystemZISelLowering.cpp b/contrib/llvm-project/llvm/lib/Target/SystemZ/SystemZISelLowering.cpp
index 5dca792dc89a..0b3059df124e 100644
--- a/contrib/llvm-project/llvm/lib/Target/SystemZ/SystemZISelLowering.cpp
+++ b/contrib/llvm-project/llvm/lib/Target/SystemZ/SystemZISelLowering.cpp
@@ -8488,11 +8488,13 @@ SystemZTargetLowering::emitMemMemWrapper(MachineInstr &MI,
           .addReg(RemSrcReg).addImm(SrcDisp);
       MBB->addSuccessor(AllDoneMBB);
       MBB = AllDoneMBB;
-      if (EndMBB) {
+      if (Opcode != SystemZ::MVC) {
         EXRL_MIB.addReg(SystemZ::CC, RegState::ImplicitDefine);
-        MBB->addLiveIn(SystemZ::CC);
+        if (EndMBB)
+          MBB->addLiveIn(SystemZ::CC);
       }
     }
+    MF.getProperties().reset(MachineFunctionProperties::Property::NoPHIs);
   }
 
   // Handle any remaining bytes with straight-line code.
diff --git a/contrib/llvm-project/llvm/lib/Target/X86/X86FrameLowering.cpp b/contrib/llvm-project/llvm/lib/Target/X86/X86FrameLowering.cpp
index 1606413c382b..df9aaddd5729 100644
--- a/contrib/llvm-project/llvm/lib/Target/X86/X86FrameLowering.cpp
+++ b/contrib/llvm-project/llvm/lib/Target/X86/X86FrameLowering.cpp
@@ -1557,7 +1557,19 @@ void X86FrameLowering::emitPrologue(MachineFunction &MF,
       Fn.arg_size() == 2) {
     StackSize += 8;
     MFI.setStackSize(StackSize);
-    emitSPUpdate(MBB, MBBI, DL, -8, /*InEpilogue=*/false);
+
+    // Update the stack pointer by pushing a register. This is the instruction
+    // emitted that would be end up being emitted by a call to `emitSPUpdate`.
+    // Hard-coding the update to a push avoids emitting a second
+    // `STACKALLOC_W_PROBING` instruction in the save block: We know that stack
+    // probing isn't needed anyways for an 8-byte update.
+    // Pushing a register leaves us in a similar situation to a regular
+    // function call where we know that the address at (rsp-8) is writeable.
+    // That way we avoid any off-by-ones with stack probing for additional
+    // stack pointer updates later on.
+    BuildMI(MBB, MBBI, DL, TII.get(X86::PUSH64r))
+        .addReg(X86::RAX, RegState::Undef)
+        .setMIFlag(MachineInstr::FrameSetup);
   }
 
   // If this is x86-64 and the Red Zone is not disabled, if we are a leaf