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llvm-mirror/test/CodeGen/Hexagon/swp-reuse-phi-6.ll
James Molloy 25cc728d30 [ModuloSchedule] Peel out prologs and epilogs, generate actual code
Summary:
This extends the PeelingModuloScheduleExpander to generate prolog and epilog code,
and correctly stitch uses through the prolog, kernel, epilog DAG.

The key concept in this patch is to ensure that all transforms are *local*; only a
function of a block and its immediate predecessor and successor. By defining the problem in this way
we can inductively rewrite the entire DAG using only local knowledge that is easy to
reason about.

For example, we assume that all prologs and epilogs are near-perfect clones of the
steady-state kernel. This means that if a block has an instruction that is predicated out,
we can redirect all users of that instruction to that equivalent instruction in our
immediate predecessor. As all blocks are clones, every instruction must have an equivalent in
every other block.

Similarly we can make the assumption by construction that if a value defined in a block is used
outside that block, the only possible user is its immediate successors. We maintain this
even for values that are used outside the loop by creating a limited form of LCSSA.

This code isn't small, but it isn't complex.

Enabled a bunch of testing from Hexagon. There are a couple of tests not enabled yet;
I'm about 80% sure there isn't buggy codegen but the tests are checking for patterns
that we don't produce. Those still need a bit more investigation. In the meantime we
(Google) are happy with the code produced by this on our downstream SMS implementation,
and believe it generates correct code.

Subscribers: mgorny, hiraditya, jsji, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D68205

llvm-svn: 373462
2019-10-02 12:46:44 +00:00

107 lines
5.9 KiB
LLVM

; RUN: llc -march=hexagon < %s -pipeliner-experimental-cg=true | FileCheck %s
; Test that the pipeliner generates correct code when attempting to reuse
; an existing phi. This test case contains a phi that references another
; phi (the value from the previous iteration), and when there is a use that
; is schedule in a later iteration. When this occurs, the pipeliner was
; using a value from the wrong iteration.
; CHECK: loop0(.LBB0_[[LOOP:.]],
; CHECK: .LBB0_[[LOOP]]:
; CHECK: vlalign([[VREG1:v([0-9]+)]],[[VREG2:v([0-9]+)]],#2)
; CHECK: [[VREG2]]:{{[0-9]+}} = vcombine([[VREG1]],v{{[0-9]+}})
; CHECK: }{{[ \t]*}}:endloop0
; Function Attrs: nounwind
define void @f0(i32 %a0, i32 %a1, i8* %a2, <16 x i32>* %a3) #0 {
b0:
%v0 = shl nsw i32 %a0, 1
%v1 = sub i32 0, %v0
%v2 = sub i32 0, %a0
%v3 = getelementptr inbounds i8, i8* %a2, i32 %v1
%v4 = getelementptr inbounds i8, i8* %a2, i32 %v2
%v5 = getelementptr inbounds i8, i8* %a2, i32 %a0
%v6 = getelementptr inbounds i8, i8* %a2, i32 %v0
%v7 = getelementptr inbounds i8, i8* %v6, i32 64
%v8 = bitcast i8* %v7 to <16 x i32>*
%v9 = getelementptr inbounds i8, i8* %v5, i32 64
%v10 = bitcast i8* %v9 to <16 x i32>*
%v11 = getelementptr inbounds i8, i8* %a2, i32 64
%v12 = bitcast i8* %v11 to <16 x i32>*
%v13 = getelementptr inbounds i8, i8* %v4, i32 64
%v14 = bitcast i8* %v13 to <16 x i32>*
%v15 = getelementptr inbounds i8, i8* %v3, i32 64
%v16 = bitcast i8* %v15 to <16 x i32>*
br label %b1
b1: ; preds = %b1, %b0
%v17 = phi <16 x i32>* [ %v59, %b1 ], [ %a3, %b0 ]
%v18 = phi <16 x i32>* [ %v34, %b1 ], [ %v8, %b0 ]
%v19 = phi <16 x i32>* [ %v32, %b1 ], [ %v10, %b0 ]
%v20 = phi <16 x i32>* [ %v30, %b1 ], [ %v12, %b0 ]
%v21 = phi <16 x i32>* [ %v28, %b1 ], [ %v14, %b0 ]
%v22 = phi <16 x i32>* [ %v26, %b1 ], [ %v16, %b0 ]
%v23 = phi <32 x i32> [ %v39, %b1 ], [ undef, %b0 ]
%v24 = phi <32 x i32> [ %v23, %b1 ], [ undef, %b0 ]
%v25 = phi i32 [ %v60, %b1 ], [ %a1, %b0 ]
%v26 = getelementptr inbounds <16 x i32>, <16 x i32>* %v22, i32 1
%v27 = load <16 x i32>, <16 x i32>* %v22, align 64
%v28 = getelementptr inbounds <16 x i32>, <16 x i32>* %v21, i32 1
%v29 = load <16 x i32>, <16 x i32>* %v21, align 64
%v30 = getelementptr inbounds <16 x i32>, <16 x i32>* %v20, i32 1
%v31 = load <16 x i32>, <16 x i32>* %v20, align 64
%v32 = getelementptr inbounds <16 x i32>, <16 x i32>* %v19, i32 1
%v33 = load <16 x i32>, <16 x i32>* %v19, align 64
%v34 = getelementptr inbounds <16 x i32>, <16 x i32>* %v18, i32 1
%v35 = load <16 x i32>, <16 x i32>* %v18, align 64
%v36 = tail call <32 x i32> @llvm.hexagon.V6.vaddubh(<16 x i32> %v27, <16 x i32> %v35) #2
%v37 = tail call <32 x i32> @llvm.hexagon.V6.vmpybus.acc(<32 x i32> %v36, <16 x i32> %v31, i32 101058054) #2
%v38 = tail call <32 x i32> @llvm.hexagon.V6.vcombine(<16 x i32> %v33, <16 x i32> %v29) #2
%v39 = tail call <32 x i32> @llvm.hexagon.V6.vmpabus.acc(<32 x i32> %v37, <32 x i32> %v38, i32 67372036) #2
%v40 = tail call <16 x i32> @llvm.hexagon.V6.lo(<32 x i32> %v23) #2
%v41 = tail call <16 x i32> @llvm.hexagon.V6.lo(<32 x i32> %v24) #2
%v42 = tail call <16 x i32> @llvm.hexagon.V6.vlalignbi(<16 x i32> %v40, <16 x i32> %v41, i32 2) #2
%v43 = tail call <16 x i32> @llvm.hexagon.V6.hi(<32 x i32> %v23) #2
%v44 = tail call <16 x i32> @llvm.hexagon.V6.hi(<32 x i32> %v24) #2
%v45 = tail call <16 x i32> @llvm.hexagon.V6.vlalignbi(<16 x i32> %v43, <16 x i32> %v44, i32 2) #2
%v46 = tail call <16 x i32> @llvm.hexagon.V6.lo(<32 x i32> %v39) #2
%v47 = tail call <16 x i32> @llvm.hexagon.V6.valignbi(<16 x i32> %v46, <16 x i32> %v40, i32 2) #2
%v48 = tail call <16 x i32> @llvm.hexagon.V6.hi(<32 x i32> %v39) #2
%v49 = tail call <16 x i32> @llvm.hexagon.V6.valignbi(<16 x i32> %v48, <16 x i32> %v43, i32 2) #2
%v50 = tail call <16 x i32> @llvm.hexagon.V6.vaddh(<16 x i32> %v45, <16 x i32> %v43) #2
%v51 = tail call <16 x i32> @llvm.hexagon.V6.vaddh(<16 x i32> %v40, <16 x i32> %v47) #2
%v52 = tail call <16 x i32> @llvm.hexagon.V6.vaddh(<16 x i32> %v42, <16 x i32> %v47) #2
%v53 = tail call <16 x i32> @llvm.hexagon.V6.vmpyiwb.acc(<16 x i32> %v52, <16 x i32> %v40, i32 101058054) #2
%v54 = tail call <16 x i32> @llvm.hexagon.V6.vmpyiwb.acc(<16 x i32> %v53, <16 x i32> %v50, i32 67372036) #2
%v55 = tail call <16 x i32> @llvm.hexagon.V6.vaddh(<16 x i32> %v45, <16 x i32> %v49) #2
%v56 = tail call <16 x i32> @llvm.hexagon.V6.vmpyiwb.acc(<16 x i32> %v55, <16 x i32> %v43, i32 101058054) #2
%v57 = tail call <16 x i32> @llvm.hexagon.V6.vmpyiwb.acc(<16 x i32> %v56, <16 x i32> %v51, i32 67372036) #2
%v58 = tail call <16 x i32> @llvm.hexagon.V6.vshuffob(<16 x i32> %v57, <16 x i32> %v54) #2
%v59 = getelementptr inbounds <16 x i32>, <16 x i32>* %v17, i32 1
store <16 x i32> %v58, <16 x i32>* %v17, align 64
%v60 = add nsw i32 %v25, -64
%v61 = icmp sgt i32 %v25, 128
br i1 %v61, label %b1, label %b2
b2: ; preds = %b1
ret void
}
; Function Attrs: nounwind readnone
declare <32 x i32> @llvm.hexagon.V6.vcombine(<16 x i32>, <16 x i32>) #1
declare <32 x i32> @llvm.hexagon.V6.vmpabus.acc(<32 x i32>, <32 x i32>, i32) #1
declare <16 x i32> @llvm.hexagon.V6.hi(<32 x i32>) #1
declare <16 x i32> @llvm.hexagon.V6.vlalignbi(<16 x i32>, <16 x i32>, i32) #1
declare <16 x i32> @llvm.hexagon.V6.lo(<32 x i32>) #1
declare <16 x i32> @llvm.hexagon.V6.valignbi(<16 x i32>, <16 x i32>, i32) #1
declare <16 x i32> @llvm.hexagon.V6.vaddh(<16 x i32>, <16 x i32>) #1
declare <32 x i32> @llvm.hexagon.V6.vaddubh(<16 x i32>, <16 x i32>) #1
declare <32 x i32> @llvm.hexagon.V6.vmpybus.acc(<32 x i32>, <16 x i32>, i32) #1
declare <16 x i32> @llvm.hexagon.V6.vmpyiwb.acc(<16 x i32>, <16 x i32>, i32) #1
declare <16 x i32> @llvm.hexagon.V6.vshuffob(<16 x i32>, <16 x i32>) #1
attributes #0 = { nounwind "target-cpu"="hexagonv65" "target-features"="+hvxv65,+hvx-length64b" }
attributes #1 = { nounwind readnone }
attributes #2 = { nounwind }