[llvm] r359545 - Fix for bug 41512: lower INSERT_VECTOR_ELT(ZeroVec, 0, Elt) to SCALAR_TO_VECTOR(Elt) for all SSE flavors
Simon Pilgrim via llvm-commits
llvm-commits at lists.llvm.org
Tue Apr 30 03:18:25 PDT 2019
Author: rksimon
Date: Tue Apr 30 03:18:25 2019
New Revision: 359545
URL: http://llvm.org/viewvc/llvm-project?rev=359545&view=rev
Log:
Fix for bug 41512: lower INSERT_VECTOR_ELT(ZeroVec, 0, Elt) to SCALAR_TO_VECTOR(Elt) for all SSE flavors
Current LLVM uses pxor+pinsrb on SSE4+ for INSERT_VECTOR_ELT(ZeroVec, 0, Elt) insead of much simpler movd.
INSERT_VECTOR_ELT(ZeroVec, 0, Elt) is idiomatic construct which is used e.g. for _mm_cvtsi32_si128(Elt) and for lowest element initialization in _mm_set_epi32.
So such inefficient lowering leads to significant performance digradations in ceratin cases switching from SSSE3 to SSE4.
https://bugs.llvm.org/show_bug.cgi?id=41512
Here INSERT_VECTOR_ELT(ZeroVec, 0, Elt) is simply converted to SCALAR_TO_VECTOR(Elt) when applicable since latter is closer match to desired behavior and always efficiently lowered to movd and alike.
Committed on behalf of @Serge_Preis (Serge Preis)
Differential Revision: https://reviews.llvm.org/D60852
Modified:
llvm/trunk/lib/Target/X86/X86ISelLowering.cpp
llvm/trunk/test/CodeGen/X86/insertelement-zero.ll
Modified: llvm/trunk/lib/Target/X86/X86ISelLowering.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/X86/X86ISelLowering.cpp?rev=359545&r1=359544&r2=359545&view=diff
==============================================================================
--- llvm/trunk/lib/Target/X86/X86ISelLowering.cpp (original)
+++ llvm/trunk/lib/Target/X86/X86ISelLowering.cpp Tue Apr 30 03:18:25 2019
@@ -17019,6 +17019,14 @@ SDValue X86TargetLowering::LowerINSERT_V
}
assert(VT.is128BitVector() && "Only 128-bit vector types should be left!");
+ // This will be just movd/movq/movss/movsd.
+ if (IdxVal == 0 && ISD::isBuildVectorAllZeros(N0.getNode()) &&
+ (EltVT == MVT::i32 || EltVT == MVT::f32 || EltVT == MVT::f64 ||
+ EltVT == MVT::i64)) {
+ N1 = DAG.getNode(ISD::SCALAR_TO_VECTOR, dl, VT, N1);
+ return getShuffleVectorZeroOrUndef(N1, 0, true, Subtarget, DAG);
+ }
+
// Transform it so it match pinsr{b,w} which expects a GR32 as its second
// argument. SSE41 required for pinsrb.
if (VT == MVT::v8i16 || (VT == MVT::v16i8 && Subtarget.hasSSE41())) {
Modified: llvm/trunk/test/CodeGen/X86/insertelement-zero.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/CodeGen/X86/insertelement-zero.ll?rev=359545&r1=359544&r2=359545&view=diff
==============================================================================
--- llvm/trunk/test/CodeGen/X86/insertelement-zero.ll (original)
+++ llvm/trunk/test/CodeGen/X86/insertelement-zero.ll Tue Apr 30 03:18:25 2019
@@ -500,45 +500,19 @@ define <32 x i8> @insert_v32i8_z12345678
ret <32 x i8> %4
}
-; FIXME: Prefer 'movd' over 'pinsr' to element 0.
-
define <4 x i32> @PR41512(i32 %x, i32 %y) {
-; SSE2-LABEL: PR41512:
-; SSE2: # %bb.0:
-; SSE2-NEXT: movd %edi, %xmm0
-; SSE2-NEXT: movd %esi, %xmm1
-; SSE2-NEXT: punpcklqdq {{.*#+}} xmm0 = xmm0[0],xmm1[0]
-; SSE2-NEXT: retq
-;
-; SSE3-LABEL: PR41512:
-; SSE3: # %bb.0:
-; SSE3-NEXT: movd %edi, %xmm0
-; SSE3-NEXT: movd %esi, %xmm1
-; SSE3-NEXT: punpcklqdq {{.*#+}} xmm0 = xmm0[0],xmm1[0]
-; SSE3-NEXT: retq
-;
-; SSSE3-LABEL: PR41512:
-; SSSE3: # %bb.0:
-; SSSE3-NEXT: movd %edi, %xmm0
-; SSSE3-NEXT: movd %esi, %xmm1
-; SSSE3-NEXT: punpcklqdq {{.*#+}} xmm0 = xmm0[0],xmm1[0]
-; SSSE3-NEXT: retq
-;
-; SSE41-LABEL: PR41512:
-; SSE41: # %bb.0:
-; SSE41-NEXT: pxor %xmm1, %xmm1
-; SSE41-NEXT: pxor %xmm0, %xmm0
-; SSE41-NEXT: pinsrd $0, %edi, %xmm0
-; SSE41-NEXT: pinsrd $0, %esi, %xmm1
-; SSE41-NEXT: punpcklqdq {{.*#+}} xmm0 = xmm0[0],xmm1[0]
-; SSE41-NEXT: retq
+; SSE-LABEL: PR41512:
+; SSE: # %bb.0:
+; SSE-NEXT: movd %edi, %xmm0
+; SSE-NEXT: movd %esi, %xmm1
+; SSE-NEXT: punpcklqdq {{.*#+}} xmm0 = xmm0[0],xmm1[0]
+; SSE-NEXT: retq
;
; AVX-LABEL: PR41512:
; AVX: # %bb.0:
-; AVX-NEXT: vpxor %xmm0, %xmm0, %xmm0
-; AVX-NEXT: vpinsrd $0, %edi, %xmm0, %xmm1
-; AVX-NEXT: vpinsrd $0, %esi, %xmm0, %xmm0
-; AVX-NEXT: vpunpcklqdq {{.*#+}} xmm0 = xmm1[0],xmm0[0]
+; AVX-NEXT: vmovd %edi, %xmm0
+; AVX-NEXT: vmovd %esi, %xmm1
+; AVX-NEXT: vpunpcklqdq {{.*#+}} xmm0 = xmm0[0],xmm1[0]
; AVX-NEXT: retq
%ins1 = insertelement <4 x i32> <i32 undef, i32 0, i32 undef, i32 undef>, i32 %x, i32 0
%ins2 = insertelement <4 x i32> <i32 undef, i32 0, i32 undef, i32 undef>, i32 %y, i32 0
@@ -547,46 +521,24 @@ define <4 x i32> @PR41512(i32 %x, i32 %y
}
define <4 x i64> @PR41512_v4i64(i64 %x, i64 %y) {
-; SSE2-LABEL: PR41512_v4i64:
-; SSE2: # %bb.0:
-; SSE2-NEXT: movq %rdi, %xmm0
-; SSE2-NEXT: movq %rsi, %xmm1
-; SSE2-NEXT: retq
-;
-; SSE3-LABEL: PR41512_v4i64:
-; SSE3: # %bb.0:
-; SSE3-NEXT: movq %rdi, %xmm0
-; SSE3-NEXT: movq %rsi, %xmm1
-; SSE3-NEXT: retq
-;
-; SSSE3-LABEL: PR41512_v4i64:
-; SSSE3: # %bb.0:
-; SSSE3-NEXT: movq %rdi, %xmm0
-; SSSE3-NEXT: movq %rsi, %xmm1
-; SSSE3-NEXT: retq
-;
-; SSE41-LABEL: PR41512_v4i64:
-; SSE41: # %bb.0:
-; SSE41-NEXT: pxor %xmm1, %xmm1
-; SSE41-NEXT: pxor %xmm0, %xmm0
-; SSE41-NEXT: pinsrq $0, %rdi, %xmm0
-; SSE41-NEXT: pinsrq $0, %rsi, %xmm1
-; SSE41-NEXT: retq
+; SSE-LABEL: PR41512_v4i64:
+; SSE: # %bb.0:
+; SSE-NEXT: movq %rdi, %xmm0
+; SSE-NEXT: movq %rsi, %xmm1
+; SSE-NEXT: retq
;
; AVX1-LABEL: PR41512_v4i64:
; AVX1: # %bb.0:
-; AVX1-NEXT: vpxor %xmm0, %xmm0, %xmm0
-; AVX1-NEXT: vpinsrq $0, %rdi, %xmm0, %xmm1
-; AVX1-NEXT: vpinsrq $0, %rsi, %xmm0, %xmm0
-; AVX1-NEXT: vinsertf128 $1, %xmm0, %ymm1, %ymm0
+; AVX1-NEXT: vmovq %rdi, %xmm0
+; AVX1-NEXT: vmovq %rsi, %xmm1
+; AVX1-NEXT: vinsertf128 $1, %xmm1, %ymm0, %ymm0
; AVX1-NEXT: retq
;
; AVX2-LABEL: PR41512_v4i64:
; AVX2: # %bb.0:
-; AVX2-NEXT: vpxor %xmm0, %xmm0, %xmm0
-; AVX2-NEXT: vpinsrq $0, %rdi, %xmm0, %xmm1
-; AVX2-NEXT: vpinsrq $0, %rsi, %xmm0, %xmm0
-; AVX2-NEXT: vinserti128 $1, %xmm0, %ymm1, %ymm0
+; AVX2-NEXT: vmovq %rdi, %xmm0
+; AVX2-NEXT: vmovq %rsi, %xmm1
+; AVX2-NEXT: vinserti128 $1, %xmm1, %ymm0, %ymm0
; AVX2-NEXT: retq
%ins1 = insertelement <4 x i64> <i64 undef, i64 0, i64 undef, i64 undef>, i64 %x, i32 0
%ins2 = insertelement <4 x i64> <i64 undef, i64 0, i64 undef, i64 undef>, i64 %y, i32 0
@@ -648,42 +600,18 @@ define <8 x float> @PR41512_v8f32(float
}
define <4 x i32> @PR41512_loads(i32* %p1, i32* %p2) {
-; SSE2-LABEL: PR41512_loads:
-; SSE2: # %bb.0:
-; SSE2-NEXT: movss {{.*#+}} xmm0 = mem[0],zero,zero,zero
-; SSE2-NEXT: movss {{.*#+}} xmm1 = mem[0],zero,zero,zero
-; SSE2-NEXT: movlhps {{.*#+}} xmm0 = xmm0[0],xmm1[0]
-; SSE2-NEXT: retq
-;
-; SSE3-LABEL: PR41512_loads:
-; SSE3: # %bb.0:
-; SSE3-NEXT: movss {{.*#+}} xmm0 = mem[0],zero,zero,zero
-; SSE3-NEXT: movss {{.*#+}} xmm1 = mem[0],zero,zero,zero
-; SSE3-NEXT: movlhps {{.*#+}} xmm0 = xmm0[0],xmm1[0]
-; SSE3-NEXT: retq
-;
-; SSSE3-LABEL: PR41512_loads:
-; SSSE3: # %bb.0:
-; SSSE3-NEXT: movss {{.*#+}} xmm0 = mem[0],zero,zero,zero
-; SSSE3-NEXT: movss {{.*#+}} xmm1 = mem[0],zero,zero,zero
-; SSSE3-NEXT: movlhps {{.*#+}} xmm0 = xmm0[0],xmm1[0]
-; SSSE3-NEXT: retq
-;
-; SSE41-LABEL: PR41512_loads:
-; SSE41: # %bb.0:
-; SSE41-NEXT: pxor %xmm1, %xmm1
-; SSE41-NEXT: pxor %xmm0, %xmm0
-; SSE41-NEXT: pinsrd $0, (%rdi), %xmm0
-; SSE41-NEXT: pinsrd $0, (%rsi), %xmm1
-; SSE41-NEXT: punpcklqdq {{.*#+}} xmm0 = xmm0[0],xmm1[0]
-; SSE41-NEXT: retq
+; SSE-LABEL: PR41512_loads:
+; SSE: # %bb.0:
+; SSE-NEXT: movss {{.*#+}} xmm0 = mem[0],zero,zero,zero
+; SSE-NEXT: movss {{.*#+}} xmm1 = mem[0],zero,zero,zero
+; SSE-NEXT: movlhps {{.*#+}} xmm0 = xmm0[0],xmm1[0]
+; SSE-NEXT: retq
;
; AVX-LABEL: PR41512_loads:
; AVX: # %bb.0:
-; AVX-NEXT: vpxor %xmm0, %xmm0, %xmm0
-; AVX-NEXT: vpinsrd $0, (%rdi), %xmm0, %xmm1
-; AVX-NEXT: vpinsrd $0, (%rsi), %xmm0, %xmm0
-; AVX-NEXT: vpunpcklqdq {{.*#+}} xmm0 = xmm1[0],xmm0[0]
+; AVX-NEXT: vmovss {{.*#+}} xmm0 = mem[0],zero,zero,zero
+; AVX-NEXT: vmovss {{.*#+}} xmm1 = mem[0],zero,zero,zero
+; AVX-NEXT: vmovlhps {{.*#+}} xmm0 = xmm0[0],xmm1[0]
; AVX-NEXT: retq
%x = load i32, i32* %p1
%y = load i32, i32* %p2
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