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db9853f118
Summary: We teach alias analysis that invariant.start is readonly. This helps with GVN and memcopy optimizations that currently treat. invariant.start as a clobber. We need to treat this as readonly, so that DSE does not incorrectly remove stores prior to the invariant.start Reviewers: sanjoy, reames, majnemer, dberlin Subscribers: llvm-commits Differential Revision: https://reviews.llvm.org/D23214 llvm-svn: 278138
50 lines
2.2 KiB
LLVM
50 lines
2.2 KiB
LLVM
; MemCpy optimizations should take place even in presence of invariant.start
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; RUN: opt < %s -basicaa -memcpyopt -dse -S | FileCheck %s
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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"
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target triple = "i686-apple-darwin9"
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%0 = type { x86_fp80, x86_fp80 }
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declare void @llvm.memcpy.p0i8.p0i8.i32(i8* nocapture, i8* nocapture, i32, i32,
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i1) nounwind
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declare void @llvm.memcpy.p0i8.p0i8.i64(i8* nocapture, i8* nocapture readonly,
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i64, i32, i1)
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declare void @llvm.memset.p0i8.i64(i8* nocapture, i8, i64, i32, i1)
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declare {}* @llvm.invariant.start.p0i8(i64, i8* nocapture) nounwind readonly
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; FIXME: The invariant.start does not modify %P.
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; The intermediate alloca and one of the memcpy's should be eliminated, the
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; other should be transformed to a memmove.
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define void @test1(i8* %P, i8* %Q) nounwind {
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%memtmp = alloca %0, align 16
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%R = bitcast %0* %memtmp to i8*
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call void @llvm.memcpy.p0i8.p0i8.i32(i8* %R, i8* %P, i32 32, i32 16, i1 false)
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%i = call {}* @llvm.invariant.start.p0i8(i64 32, i8* %P)
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call void @llvm.memcpy.p0i8.p0i8.i32(i8* %Q, i8* %R, i32 32, i32 16, i1 false)
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ret void
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; CHECK-LABEL: @test1(
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; CHECK-NEXT: %memtmp = alloca %0, align 16
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; CHECK-NEXT: %R = bitcast %0* %memtmp to i8*
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; CHECK-NEXT: call void @llvm.memcpy.p0i8.p0i8.i32(i8* %R, i8* %P, i32 32, i32 16, i1 false)
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; CHECK-NEXT: %i = call {}* @llvm.invariant.start.p0i8(i64 32, i8* %P)
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; CHECK-NEXT: call void @llvm.memcpy.p0i8.p0i8.i32(i8* %Q, i8* %R, i32 32, i32 16, i1 false)
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; CHECK-NEXT: ret void
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}
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; The invariant.start intrinsic does not inhibit tranforming the memcpy to a
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; memset.
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define void @test2(i8* %dst1, i8* %dst2, i8 %c) {
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; CHECK-LABEL: define void @test2(
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; CHECK-NEXT: call void @llvm.memset.p0i8.i64(i8* %dst1, i8 %c, i64 128, i32 1, i1 false)
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; CHECK-NEXT: %i = call {}* @llvm.invariant.start.p0i8(i64 32, i8* %dst1)
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; CHECK-NEXT: call void @llvm.memset.p0i8.i64(i8* %dst2, i8 %c, i64 128, i32 8, i1 false)
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; CHECK-NEXT: ret void
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call void @llvm.memset.p0i8.i64(i8* %dst1, i8 %c, i64 128, i32 1, i1 false)
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%i = call {}* @llvm.invariant.start.p0i8(i64 32, i8* %dst1)
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call void @llvm.memcpy.p0i8.p0i8.i64(i8* %dst2, i8* %dst1, i64 128, i32 8, i1 false)
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ret void
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}
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