mirror of
https://github.com/RPCS3/llvm-mirror.git
synced 2024-10-19 11:02:59 +02:00
d04766ba20
This intrinsic takes two arguments, ``%ptr`` and ``%offset``. It loads a 32-bit value from the address ``%ptr + %offset``, adds ``%ptr`` to that value and returns it. The constant folder specifically recognizes the form of this intrinsic and the constant initializers it may load from; if a loaded constant initializer is known to have the form ``i32 trunc(x - %ptr)``, the intrinsic call is folded to ``x``. LLVM provides that the calculation of such a constant initializer will not overflow at link time under the medium code model if ``x`` is an ``unnamed_addr`` function. However, it does not provide this guarantee for a constant initializer folded into a function body. This intrinsic can be used to avoid the possibility of overflows when loading from such a constant. Differential Revision: http://reviews.llvm.org/D18367 llvm-svn: 267223
20 lines
677 B
LLVM
20 lines
677 B
LLVM
; RUN: opt < %s -instsimplify -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-f80:32:32-n8:16:32"
|
|
target triple = "i386-unknown-linux-gnu"
|
|
|
|
@a = external global i8
|
|
|
|
@c1 = constant [3 x i32] [i32 0, i32 0,
|
|
i32 sub (i32 ptrtoint (i8* @a to i32), i32 ptrtoint (i32* getelementptr ([3 x i32], [3 x i32]* @c1, i32 0, i32 2) to i32))
|
|
]
|
|
|
|
; CHECK: @f1
|
|
define i8* @f1() {
|
|
; CHECK: ret i8* @a
|
|
%l = call i8* @llvm.load.relative.i32(i8* bitcast (i32* getelementptr ([3 x i32], [3 x i32]* @c1, i32 0, i32 2) to i8*), i32 0)
|
|
ret i8* %l
|
|
}
|
|
|
|
declare i8* @llvm.load.relative.i32(i8*, i32)
|