llvm-6502/test/Analysis/BasicAA/assume.ll
Hal Finkel 8ef7b17dfc Add @llvm.assume, lowering, and some basic properties
This is the first commit in a series that add an @llvm.assume intrinsic which
can be used to provide the optimizer with a condition it may assume to be true
(when the control flow would hit the intrinsic call). Some basic properties are added here:

 - llvm.invariant(true) is dead.
 - llvm.invariant(false) is unreachable (this directly corresponds to the
   documented behavior of MSVC's __assume(0)), so is llvm.invariant(undef).

The intrinsic is tagged as writing arbitrarily, in order to maintain control
dependencies. BasicAA has been updated, however, to return NoModRef for any
particular location-based query so that we don't unnecessarily block code
motion.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@213973 91177308-0d34-0410-b5e6-96231b3b80d8
2014-07-25 21:13:35 +00:00

24 lines
1.3 KiB
LLVM

; RUN: opt < %s -basicaa -aa-eval -print-all-alias-modref-info -disable-output 2>&1 | FileCheck %s
target datalayout = "e-p:32:32:32-i1:8:32-i8:8:32-i16:16:32-i32:32:32-i64:32:32-f32:32:32-f64:32:32-v64:32:64-v128:32:128-a0:0:32-n32"
declare void @llvm.memcpy.p0i8.p0i8.i64(i8* nocapture, i8* nocapture, i64, i32, i1) #0
declare void @llvm.assume(i1) #0
define void @test1(i8* %P, i8* %Q) nounwind ssp {
tail call void @llvm.assume(i1 true)
tail call void @llvm.memcpy.p0i8.p0i8.i64(i8* %P, i8* %Q, i64 12, i32 1, i1 false)
ret void
; CHECK-LABEL: Function: test1:
; CHECK: MayAlias: i8* %P, i8* %Q
; CHECK: NoModRef: Ptr: i8* %P <-> tail call void @llvm.assume(i1 true)
; CHECK: NoModRef: Ptr: i8* %Q <-> tail call void @llvm.assume(i1 true)
; CHECK: Both ModRef: Ptr: i8* %P <-> tail call void @llvm.memcpy.p0i8.p0i8.i64(i8* %P, i8* %Q, i64 12, i32 1, i1 false)
; CHECK: Both ModRef: Ptr: i8* %Q <-> tail call void @llvm.memcpy.p0i8.p0i8.i64(i8* %P, i8* %Q, i64 12, i32 1, i1 false)
; CHECK: NoModRef: tail call void @llvm.assume(i1 true) <-> tail call void @llvm.memcpy.p0i8.p0i8.i64(i8* %P, i8* %Q, i64 12, i32 1, i1 false)
; CHECK: NoModRef: tail call void @llvm.memcpy.p0i8.p0i8.i64(i8* %P, i8* %Q, i64 12, i32 1, i1 false) <-> tail call void @llvm.assume(i1 true)
}
attributes #0 = { nounwind }