[CodeExtractor] Do not extract unsafe lifetime markers

Lifetime markers which reference inputs to the extraction region are not
safe to extract. Example ('rhs' will be extracted):

```
               entry:
              +------------+
              | x = alloca |
              | y = alloca |
              +------------+
             /              \
   lhs:                      rhs:
  +-------------------+     +-------------------+
  | lifetime_start(x) |     | lifetime_start(x) |
  | use(x)            |     | lifetime_start(y) |
  | lifetime_end(x)   |     | use(x, y)         |
  | lifetime_start(y) |     | lifetime_end(y)   |
  | use(y)            |     | lifetime_end(x)   |
  | lifetime_end(y)   |     +-------------------+
  +-------------------+
```

Prior to extraction, the stack coloring pass sees that the slots for 'x'
and 'y' are in-use at the same time. After extraction, the coloring pass
infers that 'x' and 'y' are *not* in-use concurrently, because markers
from 'rhs' are no longer available to help decide otherwise.

This leads to a miscompile, because the stack slots actually are in-use
concurrently in the extracted function.

Fix this by moving lifetime start/end markers for memory regions defined
in the calling function around the call to the extracted function.

Fixes llvm.org/PR39671 (rdar://45939472).

Differential Revision: https://reviews.llvm.org/D55967

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@350420 91177308-0d34-0410-b5e6-96231b3b80d8

test/Transforms/CodeExtractor/PartialInlineAlloca4.ll

@@ -6,10 +6,14 @@
 
 @g = external local_unnamed_addr global i32, align 4
 
+; CHECK-LABEL: define{{.*}}@caller(
+; CHECK: call void @llvm.lifetime.start.p0i8(i64 -1, i8* %tmp.i)
+; CHECK-NEXT: call void @callee_unknown_use1.{{.*}}(i8* %tmp.i
+; CHECK-NEXT: call void @llvm.lifetime.end.p0i8(i64 -1, i8* %tmp.i)
+
 define i32 @callee_unknown_use1(i32 %arg) local_unnamed_addr #0 {
 ; CHECK-LABEL:define{{.*}}@callee_unknown_use1.{{[0-9]}}
 ; CHECK-NOT: alloca
-; CHECK: call void @llvm.lifetime
 bb:
   %tmp = alloca  i8, align 4
   %tmp2 = load i32, i32* @g, align 4, !tbaa !2

test/Transforms/CodeExtractor/PartialInlineAlloca5.ll

@@ -9,7 +9,6 @@
 define i32 @callee_unknown_use2(i32 %arg) local_unnamed_addr #0 {
 ; CHECK-LABEL:define{{.*}}@callee_unknown_use2.{{[0-9]}}
 ; CHECK-NOT: alloca
-; CHECK: call void @llvm.lifetime
 bb:
   %tmp = alloca i32, align 4
   %tmp1 = bitcast i32* %tmp to i8*