llvm-mirror/test/CodeGen/AMDGPU/invariant-load-no-alias-store.ll
Matt Arsenault e1819eb4e3 DAGCombiner: Assume invariant load cannot alias a store
The motivation is to allow GatherAllAliases / FindBetterChain
to not give up on dependent loads of a pointer from constant memory.

This is important for AMDGPU, because most loads are pointers
derived from a load of a kernel argument from constant memory.

llvm-svn: 241948
2015-07-10 22:17:40 +00:00

35 lines
1.7 KiB
LLVM

; RUN: llc -march=amdgcn -verify-machineinstrs < %s | FileCheck -check-prefix=GCN %s
; GatherAllAliases gives up on trying to analyze cases where the
; pointer may have been loaded from an aliased store, so make sure
; that this works and allows moving the stores to a better chain to
; allow them to be merged merged when it's clear the pointer is loaded
; from constant/invariant memory.
; GCN-LABEL: {{^}}test_merge_store_constant_i16_invariant_global_pointer_load:
; GCN: buffer_load_dwordx2 [[PTR:v\[[0-9]+:[0-9]+\]]],
; GCN: v_mov_b32_e32 [[K:v[0-9]+]], 0x1c8007b
; GCN: buffer_store_dword [[K]], [[PTR]]
define void @test_merge_store_constant_i16_invariant_global_pointer_load(i16 addrspace(1)* addrspace(1)* dereferenceable(4096) nonnull %in) #0 {
%ptr = load i16 addrspace(1)*, i16 addrspace(1)* addrspace(1)* %in, !invariant.load !0
%ptr.1 = getelementptr i16, i16 addrspace(1)* %ptr, i64 1
store i16 123, i16 addrspace(1)* %ptr, align 4
store i16 456, i16 addrspace(1)* %ptr.1
ret void
}
; GCN-LABEL: {{^}}test_merge_store_constant_i16_invariant_constant_pointer_load:
; GCN: s_load_dwordx2 s{{\[}}[[SPTR_LO:[0-9]+]]:[[SPTR_HI:[0-9]+]]{{\]}}
; GCN: v_mov_b32_e32 [[K:v[0-9]+]], 0x1c8007b
; GCN: buffer_store_dword [[K]], s{{\[}}[[SPTR_LO]]:
define void @test_merge_store_constant_i16_invariant_constant_pointer_load(i16 addrspace(1)* addrspace(2)* dereferenceable(4096) nonnull %in) #0 {
%ptr = load i16 addrspace(1)*, i16 addrspace(1)* addrspace(2)* %in, !invariant.load !0
%ptr.1 = getelementptr i16, i16 addrspace(1)* %ptr, i64 1
store i16 123, i16 addrspace(1)* %ptr, align 4
store i16 456, i16 addrspace(1)* %ptr.1
ret void
}
!0 = !{}
attributes #0 = { nounwind }