llvm-6502/test/Transforms/GlobalOpt/alias-used.ll
Rafael Espindola d1b6ca23b4 Change how globalopt handles aliases in llvm.used.
Instead of a custom implementation of replaceAllUsesWith, we just call
replaceAllUsesWith and recreate llvm.used and llvm.compiler-used.

This change is particularity interesting because it makes llvm see
through what clang is doing with static used functions in extern "C"
contexts. With this change, running clang -O2 in

extern "C" {
  __attribute__((used)) static void foo() {}
}

produces

@llvm.used = appending global [1 x i8*] [i8* bitcast (void ()* @foo to
i8*)], section "llvm.metadata"
define internal void @foo() #0 {
entry:
  ret void
}

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@183756 91177308-0d34-0410-b5e6-96231b3b80d8
2013-06-11 17:48:06 +00:00

48 lines
1.5 KiB
LLVM

; RUN: opt < %s -globalopt -S | FileCheck %s
@c = global i8 42
@i = internal global i8 42
; CHECK: @ia = internal global i8 42
@ia = alias internal i8* @i
@llvm.used = appending global [3 x i8*] [i8* bitcast (void ()* @fa to i8*), i8* bitcast (void ()* @f to i8*), i8* @ca], section "llvm.metadata"
; CHECK-DAG: @llvm.used = appending global [3 x i8*] [i8* bitcast (void ()* @fa to i8*), i8* bitcast (void ()* @f to i8*), i8* @ca], section "llvm.metadata"
@llvm.compiler_used = appending global [4 x i8*] [i8* bitcast (void ()* @fa3 to i8*), i8* bitcast (void ()* @fa to i8*), i8* @ia, i8* @i], section "llvm.metadata"
; CHECK-DAG: @llvm.compiler_used = appending global [2 x i8*] [i8* bitcast (void ()* @fa3 to i8*), i8* @ia], section "llvm.metadata"
@sameAsUsed = global [3 x i8*] [i8* bitcast (void ()* @fa to i8*), i8* bitcast (void ()* @f to i8*), i8* @ca]
; CHECK-DAG: @sameAsUsed = global [3 x i8*] [i8* bitcast (void ()* @f to i8*), i8* bitcast (void ()* @f to i8*), i8* @c]
@other = global i32* bitcast (void ()* @fa to i32*)
; CHECK-DAG: @other = global i32* bitcast (void ()* @f to i32*)
@fa = alias internal void ()* @f
; CHECK: @fa = alias internal void ()* @f
@fa2 = alias internal void ()* @f
; CHECK-NOT: @fa2
@fa3 = alias internal void ()* @f
; CHECK: @fa3
@ca = alias internal i8* @c
; CHECK: @ca = alias internal i8* @c
define void @f() {
ret void
}
define i8* @g() {
ret i8* bitcast (void ()* @fa to i8*);
}
define i8* @g2() {
ret i8* bitcast (void ()* @fa2 to i8*);
}
define i8* @h() {
ret i8* @ca
}