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https://github.com/c64scene-ar/llvm-6502.git
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8ef7b17dfc
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
24 lines
1.3 KiB
LLVM
24 lines
1.3 KiB
LLVM
; RUN: opt < %s -basicaa -aa-eval -print-all-alias-modref-info -disable-output 2>&1 | FileCheck %s
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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"
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declare void @llvm.memcpy.p0i8.p0i8.i64(i8* nocapture, i8* nocapture, i64, i32, i1) #0
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declare void @llvm.assume(i1) #0
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define void @test1(i8* %P, i8* %Q) nounwind ssp {
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tail call void @llvm.assume(i1 true)
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tail call void @llvm.memcpy.p0i8.p0i8.i64(i8* %P, i8* %Q, i64 12, i32 1, i1 false)
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ret void
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; CHECK-LABEL: Function: test1:
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; CHECK: MayAlias: i8* %P, i8* %Q
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; CHECK: NoModRef: Ptr: i8* %P <-> tail call void @llvm.assume(i1 true)
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; CHECK: NoModRef: Ptr: i8* %Q <-> tail call void @llvm.assume(i1 true)
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; CHECK: Both ModRef: Ptr: i8* %P <-> tail call void @llvm.memcpy.p0i8.p0i8.i64(i8* %P, i8* %Q, i64 12, i32 1, i1 false)
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; CHECK: Both ModRef: Ptr: i8* %Q <-> tail call void @llvm.memcpy.p0i8.p0i8.i64(i8* %P, i8* %Q, i64 12, i32 1, i1 false)
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; 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)
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; 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)
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}
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attributes #0 = { nounwind }
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