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llvm-mirror/test/CodeGen/AArch64/GlobalISel/legalize-inserts.mir
Aditya Nandakumar 8e51f27003 [GISel]: Rework legalization algorithm for better elimination of
artifacts along with DCE

Legalization Artifacts are all those insts that are there to make the
type system happy. Currently, the target needs to say all combinations
of extends and truncs are legal and there's no way of verifying that
post legalization, we only have *truly* legal instructions. This patch
changes roughly the legalization algorithm to process all illegal insts
at one go, and then process all truncs/extends that were added to
satisfy the type constraints separately trying to combine trivial cases
until they converge. This has the added benefit that, the target
legalizerinfo can only say which truncs and extends are okay and the
artifact combiner would combine away other exts and truncs.

Updated legalization algorithm to roughly the following pseudo code.

WorkList Insts, Artifacts;
collect_all_insts_and_artifacts(Insts, Artifacts);

do {
  for (Inst in Insts)
         legalizeInstrStep(Inst, Insts, Artifacts);
  for (Artifact in Artifacts)
         tryCombineArtifact(Artifact, Insts, Artifacts);
} while(!Insts.empty());

Also, wrote a simple wrapper equivalent to SetVector, except for
erasing, it avoids moving all elements over by one and instead just
nulls them out.

llvm-svn: 318210
2017-11-14 22:42:19 +00:00

170 lines
4.8 KiB
YAML

# RUN: llc -O0 -run-pass=legalizer -global-isel %s -o - | FileCheck %s
--- |
target datalayout = "e-m:o-i64:64-i128:128-n32:64-S128"
target triple = "aarch64--"
define void @test_inserts_1() { ret void }
define void @test_inserts_2() { ret void }
define void @test_inserts_3() { ret void }
define void @test_inserts_4() { ret void }
define void @test_inserts_5() { ret void }
define void @test_inserts_6() { ret void }
define void @test_inserts_nonpow2() { ret void }
...
---
name: test_inserts_1
body: |
bb.0:
liveins: %w0
; Low part of insertion wipes out the old register entirely, so %0 gets
; forwarded to the G_STORE. Hi part is unchanged so (split) G_LOAD gets
; forwarded.
; CHECK-LABEL: name: test_inserts_1
; CHECK: [[LO:%[0-9]+]]:_(s64) = G_LOAD
; CHECK: [[HI:%[0-9]+]]:_(s64) = G_LOAD
; CHECK: G_STORE %0(s64)
; CHECK: G_STORE [[HI]]
%0:_(s64) = COPY %x0
%1:_(s32) = COPY %w1
%2:_(p0) = COPY %x2
%3:_(s128) = G_LOAD %2(p0) :: (load 16)
%4:_(s128) = G_INSERT %3(s128), %0(s64), 0
G_STORE %4(s128), %2(p0) :: (store 16)
RET_ReallyLR
...
---
name: test_inserts_2
body: |
bb.0:
liveins: %w0
; Low insertion wipes out the old register entirely, so %0 gets forwarded
; to the G_STORE again. Second insertion is real.
; CHECK-LABEL: name: test_inserts_2
; CHECK: [[LO:%[0-9]+]]:_(s64) = G_LOAD
; CHECK: [[HI:%[0-9]+]]:_(s64) = G_LOAD
; CHECK: [[NEWHI:%[0-9]+]]:_(s64) = G_INSERT [[HI]], %1(s32), 0
; CHECK: G_STORE %0(s64)
; CHECK: G_STORE [[NEWHI]]
%0:_(s64) = COPY %x0
%1:_(s32) = COPY %w1
%2:_(p0) = COPY %x2
%3:_(s128) = G_LOAD %2(p0) :: (load 16)
%4:_(s128) = G_INSERT %3(s128), %0(s64), 0
%5:_(s128) = G_INSERT %4(s128), %1(s32), 64
G_STORE %5(s128), %2(p0) :: (store 16)
RET_ReallyLR
...
---
name: test_inserts_3
body: |
bb.0:
liveins: %w0
; I'm not entirely convinced inserting a p0 into an s64 is valid, but it's
; certainly better than the alternative of directly forwarding the value
; which would cause a nasty type mismatch.
; CHECK-LABEL: name: test_inserts_3
; CHECK: [[LO:%[0-9]+]]:_(s64) = G_LOAD
; CHECK: [[HI:%[0-9]+]]:_(s64) = G_LOAD
; CHECK: [[NEWLO:%[0-9]+]]:_(s64) = G_PTRTOINT %0(p0)
; CHECK: G_STORE [[NEWLO]](s64)
; CHECK: G_STORE [[HI]]
%0:_(p0) = COPY %x0
%1:_(s32) = COPY %w1
%2:_(p0) = COPY %x2
%3:_(s128) = G_LOAD %2(p0) :: (load 16)
%4:_(s128) = G_INSERT %3(s128), %0(p0), 0
G_STORE %4(s128), %2(p0) :: (store 16)
RET_ReallyLR
...
---
name: test_inserts_4
body: |
bb.0:
liveins: %w0
; A narrow insert gets surrounded by a G_ANYEXT/G_TRUNC pair.
; CHECK-LABEL: name: test_inserts_4
; CHECK: [[VALEXT:%[0-9]+]]:_(s32) = COPY %2(s32)
; CHECK: [[VAL:%[0-9]+]]:_(s32) = G_INSERT [[VALEXT]], %1(s1), 0
; CHECK: %5:_(s8) = G_TRUNC [[VAL]](s32)
%4:_(s32) = COPY %w0
%0:_(s1) = G_TRUNC %4
%5:_(s32) = COPY %w1
%1:_(s8) = G_TRUNC %5
%2:_(p0) = COPY %x2
%3:_(s8) = G_INSERT %1(s8), %0(s1), 0
G_STORE %3(s8), %2(p0) :: (store 1)
RET_ReallyLR
...
---
name: test_inserts_5
body: |
bb.0:
liveins: %x0, %x1, %x2
; CHECK-LABEL: name: test_inserts_5
; CHECK: [[INS_LO:%[0-9]+]]:_(s32) = G_EXTRACT %2(s64), 0
; CHECK: [[VAL_LO:%[0-9]+]]:_(s64) = G_INSERT %0, [[INS_LO]](s32), 32
; CHECK: [[INS_HI:%[0-9]+]]:_(s32) = G_EXTRACT %2(s64), 32
; CHECK: [[VAL_HI:%[0-9]+]]:_(s64) = G_INSERT %1, [[INS_HI]](s32), 0
; CHECK: %4:_(s128) = G_MERGE_VALUES [[VAL_LO]](s64), [[VAL_HI]](s64)
%0:_(s64) = COPY %x0
%1:_(s64) = COPY %x1
%2:_(s64) = COPY %x2
%3:_(s128) = G_MERGE_VALUES %0, %1
%4:_(s128) = G_INSERT %3, %2, 32
%5:_(s64) = G_TRUNC %4
%x0 = COPY %5
RET_ReallyLR
...
---
name: test_inserts_6
body: |
bb.0:
liveins: %x0, %x1, %x2
; CHECK-LABEL: name: test_inserts_6
; CHECK: [[VAL_LO:%[0-9]+]]:_(s64) = G_INSERT %0, %2(s32), 32
; CHECK: %4:_(s128) = G_MERGE_VALUES [[VAL_LO]](s64), %1(s64)
%0:_(s64) = COPY %x0
%1:_(s64) = COPY %x1
%2:_(s32) = COPY %w2
%3:_(s128) = G_MERGE_VALUES %0, %1
%4:_(s128) = G_INSERT %3, %2, 32
%5:_(s64) = G_TRUNC %4
%x0 = COPY %5
RET_ReallyLR
...
---
name: test_inserts_nonpow2
body: |
bb.0:
liveins: %x0, %x1, %x2
; CHECK-LABEL: name: test_inserts_nonpow2
; CHECK: [[C:%[0-9]+]]:_(s64) = COPY %x3
; CHECK: %x0 = COPY [[C]]
%0:_(s64) = COPY %x0
%1:_(s64) = COPY %x1
%2:_(s64) = COPY %x2
%3:_(s64) = COPY %x3
%4:_(s192) = G_MERGE_VALUES %0, %1, %2
%5:_(s192) = G_INSERT %4, %3, 0
%6:_(s64), %7:_(s64), %8:_(s64) = G_UNMERGE_VALUES %5
%x0 = COPY %6
RET_ReallyLR
...