llvm-mirror/test/CodeGen/X86/lower-vec-shift.ll
Andrea Di Biagio 216ae0fd5e [X86] Improve the lowering of packed shifts by constant build_vector.
This patch teaches the backend how to efficiently lower logical and
arithmetic packed shifts on both SSE and AVX/AVX2 machines.

When possible, instead of scalarizing a vector shift, the backend should try
to expand the shift into a sequence of two packed shifts by immedate count
followed by a MOVSS/MOVSD.

Example
  (v4i32 (srl A, (build_vector < X, Y, Y, Y>)))

Can be rewritten as:
  (v4i32 (MOVSS (srl A, <Y,Y,Y,Y>), (srl A, <X,X,X,X>)))

[with X and Y ConstantInt]

The advantage is that the two new shifts from the example would be lowered into
X86ISD::VSRLI nodes. This is always cheaper than scalarizing the vector into
four scalar shifts plus four pairs of vector insert/extract.

llvm-svn: 206316
2014-04-15 19:30:48 +00:00

126 lines
2.9 KiB
LLVM

; RUN: llc < %s -mtriple=x86_64-unknown-linux-gnu -mcpu=corei7-avx | FileCheck %s --check-prefix=CHECK --check-prefix=AVX
; RUN: llc < %s -mtriple=x86_64-unknown-linux-gnu -mcpu=core2 | FileCheck %s --check-prefix=CHECK --check-prefix=SSE
; RUN: llc < %s -mtriple=x86_64-unknown-linux-gnu -mcpu=core-avx2 | FileCheck %s --check-prefix=CHECK --check-prefix=AVX2
; Verify that the following shifts are lowered into a sequence of two shifts plus
; a blend. On pre-avx2 targets, instead of scalarizing logical and arithmetic
; packed shift right by a constant build_vector the backend should always try to
; emit a simpler sequence of two shifts + blend when possible.
define <8 x i16> @test1(<8 x i16> %a) {
%lshr = lshr <8 x i16> %a, <i16 3, i16 3, i16 2, i16 2, i16 2, i16 2, i16 2, i16 2>
ret <8 x i16> %lshr
}
; CHECK-LABEL: test1
; SSE: psrlw
; SSE-NEXT: psrlw
; SSE-NEXT: movss
; AVX: vpsrlw
; AVX-NEXT: vpsrlw
; AVX-NEXT: vmovss
; AVX2: vpsrlw
; AVX2-NEXT: vpsrlw
; AVX2-NEXT: vmovss
; CHECK: ret
define <8 x i16> @test2(<8 x i16> %a) {
%lshr = lshr <8 x i16> %a, <i16 3, i16 3, i16 3, i16 3, i16 2, i16 2, i16 2, i16 2>
ret <8 x i16> %lshr
}
; CHECK-LABEL: test2
; SSE: psrlw
; SSE-NEXT: psrlw
; SSE-NEXT: movsd
; AVX: vpsrlw
; AVX-NEXT: vpsrlw
; AVX-NEXT: vmovsd
; AVX2: vpsrlw
; AVX2-NEXT: vpsrlw
; AVX2-NEXT: vmovsd
; CHECK: ret
define <4 x i32> @test3(<4 x i32> %a) {
%lshr = lshr <4 x i32> %a, <i32 3, i32 2, i32 2, i32 2>
ret <4 x i32> %lshr
}
; CHECK-LABEL: test3
; SSE: psrld
; SSE-NEXT: psrld
; SSE-NEXT: movss
; AVX: vpsrld
; AVX-NEXT: vpsrld
; AVX-NEXT: vmovss
; AVX2: vpsrlvd
; CHECK: ret
define <4 x i32> @test4(<4 x i32> %a) {
%lshr = lshr <4 x i32> %a, <i32 3, i32 3, i32 2, i32 2>
ret <4 x i32> %lshr
}
; CHECK-LABEL: test4
; SSE: psrld
; SSE-NEXT: psrld
; SSE-NEXT: movsd
; AVX: vpsrld
; AVX-NEXT: vpsrld
; AVX-NEXT: vmovsd
; AVX2: vpsrlvd
; CHECK: ret
define <8 x i16> @test5(<8 x i16> %a) {
%lshr = ashr <8 x i16> %a, <i16 3, i16 3, i16 2, i16 2, i16 2, i16 2, i16 2, i16 2>
ret <8 x i16> %lshr
}
define <8 x i16> @test6(<8 x i16> %a) {
%lshr = ashr <8 x i16> %a, <i16 3, i16 3, i16 3, i16 3, i16 2, i16 2, i16 2, i16 2>
ret <8 x i16> %lshr
}
; CHECK-LABEL: test6
; SSE: psraw
; SSE-NEXT: psraw
; SSE-NEXT: movsd
; AVX: vpsraw
; AVX-NEXT: vpsraw
; AVX-NEXT: vmovsd
; AVX2: vpsraw
; AVX2-NEXT: vpsraw
; AVX2-NEXT: vmovsd
; CHECK: ret
define <4 x i32> @test7(<4 x i32> %a) {
%lshr = ashr <4 x i32> %a, <i32 3, i32 2, i32 2, i32 2>
ret <4 x i32> %lshr
}
; CHECK-LABEL: test7
; SSE: psrad
; SSE-NEXT: psrad
; SSE-NEXT: movss
; AVX: vpsrad
; AVX-NEXT: vpsrad
; AVX-NEXT: vmovss
; AVX2: vpsravd
; CHECK: ret
define <4 x i32> @test8(<4 x i32> %a) {
%lshr = ashr <4 x i32> %a, <i32 3, i32 3, i32 2, i32 2>
ret <4 x i32> %lshr
}
; CHECK-LABEL: test8
; SSE: psrad
; SSE-NEXT: psrad
; SSE-NEXT: movsd
; AVX: vpsrad
; AVX-NEXT: vpsrad
; AVX-NEXT: vmovsd
; AVX2: vpsravd
; CHECK: ret