Commit Graph

4 Commits

Author SHA1 Message Date
Sebastian Pop b4bd0a404f [x86][aarch64] ask the backend whether it has a vector blend instruction
The code to match and produce more x86 vector blends was enabled for all
architectures even though the transform may pessimize the code for other
architectures that do not provide a vector blend instruction.

Added an aarch64 testcase to check that a VZIP instruction is generated instead
of byte movs.

Differential Revision: https://reviews.llvm.org/D44118

llvm-svn: 327132
2018-03-09 14:29:21 +00:00
Sebastian Pop 41073e8046 [AArch64] define isExtractSubvectorCheap
Following the ARM-neon backend, define isExtractSubvectorCheap to return true
when extracting low and high part of a neon register.

The patch disables a test in llvm/test/CodeGen/AArch64/arm64-ext.ll This
testcase is fragile in the sense that it requires a BUILD_VECTOR to "survive"
all DAG transforms until ISelLowering. The testcase is supposed to check that
AArch64TargetLowering::ReconstructShuffle() works, and for that we need a
BUILD_VECTOR in ISelLowering. As we now transform the BUILD_VECTOR earlier into
an VEXT + vector_shuffle, we don't have the BUILD_VECTOR pattern when we get to
ISelLowering. As there is no way to disable the combiner to only exercise the
code in ISelLowering, the patch disables the testcase.

Differential revision: https://reviews.llvm.org/D43973

llvm-svn: 326811
2018-03-06 16:54:55 +00:00
Sebastian Pop ac0bfb5938 fix PR36582
The error occurs when reading i16 elements (as in the testcase) from a v8i8
with a pattern of <0,2,4,6>. As all the data in the vector is accessed, the
operation is not a VUZP. The patch stops the pattern recognition of VUZP when
EXTRACT_VECTOR_ELT has a different element type than BUILD_VECTOR.

llvm-svn: 326722
2018-03-05 17:35:49 +00:00
Sebastian Pop c33af715d7 [AArch64] generate vuzp instead of mov
when a BUILD_VECTOR is created out of a sequence of EXTRACT_VECTOR_ELT with a
specific pattern sequence, either <0, 2, 4, ...> or <1, 3, 5, ...>, replace the
BUILD_VECTOR with either vuzp1 or vuzp2.

With this patch LLVM generates the following code for the first function fun1 in the testcase:
adrp x8, .LCPI0_0
ldr  q0, [x8, :lo12:.LCPI0_0]
tbl  v0.16b, { v0.16b }, v0.16b
ext  v1.16b, v0.16b, v0.16b, #8
uzp1 v0.8b, v0.8b, v1.8b
str  d0, [x8]
ret

Without this patch LLVM currently generates this code:
adrp    x8, .LCPI0_0
ldr     q0, [x8, :lo12:.LCPI0_0]
tbl     v0.16b, { v0.16b }, v0.16b
mov     v1.16b, v0.16b
mov     v1.b[1], v0.b[2]
mov     v1.b[2], v0.b[4]
mov     v1.b[3], v0.b[6]
mov     v1.b[4], v0.b[8]
mov     v1.b[5], v0.b[10]
mov     v1.b[6], v0.b[12]
mov     v1.b[7], v0.b[14]
str     d1, [x8]
ret

llvm-svn: 326443
2018-03-01 15:47:39 +00:00