[InstCombine][NFC] Use --check-globals flag in tests.

[yurai007]

Summary

This patch adds strings content checking to printf-2.ll via --check-globals flag.

Split off from D100724.

llvm/test/Transforms/InstCombine/printf-2.ll

-; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
+; NOTE: Assertions have been autogenerated by utils/update_test_checks.py UTC_ARGS: --check-globals
 ; Test that the printf library call simplifier works correctly.
 ;
 ; RUN: opt < %s -instcombine -S | FileCheck %s
 
 target datalayout = "e-p:32:32:32-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:32:64-f32:32:32-f64:32:64-v64:64:64-v128:128:128-a0:0:64-f80:128:128"
 
 @hello_world = constant [13 x i8] c"hello world\0A\00"
 @h = constant [2 x i8] c"h\00"
 @percent_s = constant [4 x i8] c"%s\0A\00"
 @format_str = constant [3 x i8] c"%s\00"
 @charstr = constant [2 x i8] c"a\00"
 
 declare void @printf(i8*, ...)
 
 ; Check simplification of printf with void return type.
 
+;.
+; CHECK: @[[HELLO_WORLD:[a-zA-Z0-9_$"\\.-]+]] = constant [13 x i8] c"hello world\0A\00"
+; CHECK: @[[H:[a-zA-Z0-9_$"\\.-]+]] = constant [2 x i8] c"h\00"
+; CHECK: @[[PERCENT_S:[a-zA-Z0-9_$"\\.-]+]] = constant [4 x i8] c"%s\0A\00"
+; CHECK: @[[FORMAT_STR:[a-zA-Z0-9_$"\\.-]+]] = constant [3 x i8] c"%s\00"
+; CHECK: @[[CHARSTR:[a-zA-Z0-9_$"\\.-]+]] = constant [2 x i8] c"a\00"
+; CHECK: @[[STR:[a-zA-Z0-9_$"\\.-]+]] = private unnamed_addr constant [12 x i8] c"hello world\00", align 1
+;.
 define void @test_simplify1() {
 ; CHECK-LABEL: @test_simplify1(
 ; CHECK-NEXT:    [[PUTCHAR:%.*]] = call i32 @putchar(i32 104)
 ; CHECK-NEXT:    ret void
 ;
   %fmt = getelementptr [2 x i8], [2 x i8]* @h, i32 0, i32 0
   call void (i8*, ...) @printf(i8* %fmt)
   ret void

 ; CHECK-NEXT:    [[PUTCHAR:%.*]] = call i32 @putchar(i32 97)
 ; CHECK-NEXT:    ret void
 ;
   %fmt = getelementptr [3 x i8], [3 x i8]* @format_str, i32 0, i32 0
   %str = getelementptr [2 x i8], [2 x i8]* @charstr, i32 0, i32 0
   call void (i8*, ...) @printf(i8* %fmt, i8* %str)
   ret void
 }
+;.
+; CHECK: attributes #[[ATTR0:[0-9]+]] = { nofree nounwind }
+;.