[llvm] [DWARF] Emit a worst-case prologue_end flag for pathological inputs (PR #107849)

[Orlando Cazalet-Hyams via llvm-commits]

================
@@ -1,10 +1,10 @@
-; RUN: llc -filetype=asm -mtriple=x86_64-apple-macosx12.0.0 -O0 %s -o - | FileCheck %s
+; RUN: llc -filetype=asm -mtriple=x86_64-apple-macosx12.0.0 -O0 %s -o - | FileCheck %s --implicit-check-not=prologue_end
 ; CHECK: Lfunc_begin0:
 ; CHECK-NEXT: .file{{.+}}
 ; CHECK-NEXT: .loc 1 1 0 ## test-small.c:1:0{{$}}
 ; CHECK-NEXT: .cfi_startproc
 ; CHECK-NEXT: ## %bb.{{[0-9]+}}:
-; CHECK-NEXT: .loc 1 0 1 prologue_end{{.*}}
----------------
OCHyams wrote:

(thinking out loud)
I think this test change is fine. AFAICT the original purpose of this test is to check that prologue_end doesn't get added to the first instructions. More than checking that it gets added to the final instruction, or added at all. With that line of reasoning this test update doesn't invalidate the original purpose of the test.

cc @rastogishubham as the author of this test



https://github.com/llvm/llvm-project/pull/107849