[X86] NOT FOR COMMIT. Emit lifetime markers for MXCSR temporaries.

[craig.topper]

Summary

My experimental patch for PR48033 so I can share it in the bug.

clang/lib/CodeGen/CGBuiltin.cpp

 //===---- CGBuiltin.cpp - Emit LLVM Code for builtins ---------------------===//
 //
 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
 // See https://llvm.org/LICENSE.txt for license information.
 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 //
 //===----------------------------------------------------------------------===//
 //
case X86::BI__builtin_ia32_vec_set_v4di: {
     Index &= NumElts - 1;
     // These builtins exist so we can ensure the index is an ICE and in range.
     // Otherwise we could just do this in the header file.
     return Builder.CreateInsertElement(Ops[0], Ops[1], Index);
   }
   case X86::BI_mm_setcsr:
   case X86::BI__builtin_ia32_ldmxcsr: {
     Address Tmp = CreateMemTemp(E->getArg(0)->getType());
+    llvm::Value *TmpPtr = Tmp.getPointer();
+    llvm::Value *TmpSize = EmitLifetimeStart(
+        CGM.getDataLayout().getTypeAllocSize(Tmp.getElementType()), TmpPtr);
     Builder.CreateStore(Ops[0], Tmp);
-    return Builder.CreateCall(CGM.getIntrinsic(Intrinsic::x86_sse_ldmxcsr),
+    Value *Call = Builder.CreateCall(CGM.getIntrinsic(Intrinsic::x86_sse_ldmxcsr),
                                      Builder.CreateBitCast(Tmp.getPointer(), Int8PtrTy));
+    if (TmpSize)
+      EmitLifetimeEnd(TmpSize, TmpPtr);
+    return Call;
   }
   case X86::BI_mm_getcsr:
   case X86::BI__builtin_ia32_stmxcsr: {
     Address Tmp = CreateMemTemp(E->getType());
+    llvm::Value *TmpPtr = Tmp.getPointer();
+    llvm::Value *TmpSize = EmitLifetimeStart(
+        CGM.getDataLayout().getTypeAllocSize(Tmp.getElementType()), TmpPtr);
     Builder.CreateCall(CGM.getIntrinsic(Intrinsic::x86_sse_stmxcsr),
                        Builder.CreateBitCast(Tmp.getPointer(), Int8PtrTy));
-    return Builder.CreateLoad(Tmp, "stmxcsr");
+    Value *Call = Builder.CreateLoad(Tmp, "stmxcsr");
+    if (TmpSize)
+      EmitLifetimeEnd(TmpSize, TmpPtr);
+    return Call;
   }
   case X86::BI__builtin_ia32_xsave:
   case X86::BI__builtin_ia32_xsave64:
   case X86::BI__builtin_ia32_xrstor:
   case X86::BI__builtin_ia32_xrstor64:
   case X86::BI__builtin_ia32_xsaveopt:
   case X86::BI__builtin_ia32_xsaveopt64:
   case X86::BI__builtin_ia32_xrstors: