SelectionDAG: Handle out-of-bounds index in extract vector element

Summary: This patch correctly handles undef case of EXTRACT_VECTOR_ELT node where the element index is constant and not less than vector size.

Test Plan:
CodeGen for X86 test included.
Also one incorrect regression test fixed.

Reviewers: qcolombet, chandlerc, hfinkel

Reviewed By: hfinkel

Subscribers: hfinkel, llvm-commits

Differential Revision: http://reviews.llvm.org/D9250

llvm-svn: 236584
This commit is contained in:
Pawel Bylica 2015-05-06 10:19:14 +00:00
parent c1a1c6bbed
commit a6995220b3
3 changed files with 82 additions and 3 deletions

View File

@ -3408,6 +3408,10 @@ SDValue SelectionDAG::getNode(unsigned Opcode, SDLoc DL, EVT VT, SDValue N1,
if (N1.getOpcode() == ISD::UNDEF)
return getUNDEF(VT);
// EXTRACT_VECTOR_ELT of out-of-bounds element is an UNDEF
if (N2C && N2C->getZExtValue() >= N1.getValueType().getVectorNumElements())
return getUNDEF(VT);
// EXTRACT_VECTOR_ELT of CONCAT_VECTORS is often formed while lowering is
// expanding copies of large vectors from registers.
if (N2C &&

View File

@ -1,7 +1,8 @@
; RUN: llc < %s -o - -mcpu=generic -march=x86-64 -mattr=+sse4.1 | FileCheck %s -check-prefix=SSE41
; RUN: llc < %s -o - -mcpu=generic -march=x86-64 -mattr=+avx | FileCheck %s -check-prefix=AVX
define void @pextrb(i8* nocapture %dst, <16 x i8> %foo) {
; CHECK-LABEL: extract_i8
define void @extract_i8(i8* nocapture %dst, <16 x i8> %foo) {
; AVX: vpextrb
; SSE41: pextrb
; AVX-NOT: movb
@ -11,12 +12,35 @@ define void @pextrb(i8* nocapture %dst, <16 x i8> %foo) {
ret void
}
define void @pextrw(i16* nocapture %dst, <8 x i16> %foo) {
; CHECK-LABEL: extract_i16
define void @extract_i16(i16* nocapture %dst, <8 x i16> %foo) {
; AVX: vpextrw
; SSE41: pextrw
; AVX-NOT: movw
; SSE41-NOT: movw
%vecext = extractelement <8 x i16> %foo, i32 15
%vecext = extractelement <8 x i16> %foo, i32 7
store i16 %vecext, i16* %dst, align 1
ret void
}
; CHECK-LABEL: extract_i8_undef
define void @extract_i8_undef(i8* nocapture %dst, <16 x i8> %foo) {
; AVX-NOT: vpextrb
; SSE41-NOT: pextrb
; AVX-NOT: movb
; SSE41-NOT: movb
%vecext = extractelement <16 x i8> %foo, i32 16 ; undef
store i8 %vecext, i8* %dst, align 1
ret void
}
; CHECK-LABEL: extract_i16_undef
define void @extract_i16_undef(i16* nocapture %dst, <8 x i16> %foo) {
; AVX-NOT: vpextrw
; SSE41-NOT: pextrw
; AVX-NOT: movw
; SSE41-NOT: movw
%vecext = extractelement <8 x i16> %foo, i32 9 ; undef
store i16 %vecext, i16* %dst, align 1
ret void
}

View File

@ -0,0 +1,51 @@
; RUN: llc < %s -march=x86-64 | FileCheck %s -check-prefix=X64
; RUN: llc < %s -march=x86-64 -mattr=+avx | FileCheck %s -check-prefix=AVX
; CHECK-LABEL: extractelement_index_1:
define i8 @extractelement_index_1(<32 x i8> %a) nounwind {
; X64: movaps
; AVX: vpextrb $1
%b = extractelement <32 x i8> %a, i256 1
ret i8 %b
}
; CHECK-LABEL: extractelement_index_2:
define i32 @extractelement_index_2(<8 x i32> %a) nounwind {
; X64: pshufd
; AVX: vextractf128 $1
; AVX-NEXT: vpextrd $3
%b = extractelement <8 x i32> %a, i64 7
ret i32 %b
}
; CHECK-LABEL: extractelement_index_3:
define i32 @extractelement_index_3(<8 x i32> %a) nounwind {
; CHECK-NOT: pextr
%b = extractelement <8 x i32> %a, i64 15
ret i32 %b
}
; CHECK-LABEL: extractelement_index_4:
define i32 @extractelement_index_4(<8 x i32> %a) nounwind {
; X64: movd
; AVX: vextractf128 $1
; AVX-NEXT: vmovd
%b = extractelement <8 x i32> %a, i256 4
ret i32 %b
}
; CHECK-LABEL: extractelement_index_5:
define i8 @extractelement_index_5(<32 x i8> %a, i256 %i) nounwind {
; X64: movaps
; AVX: vmovaps
%b = extractelement <32 x i8> %a, i256 %i
ret i8 %b
}
; CHECK-LABEL: extractelement_index_6:
define i8 @extractelement_index_6(<32 x i8> %a) nounwind {
; CHECK-NOT: pextr
%b = extractelement <32 x i8> %a, i256 -1
ret i8 %b
}