[X86] Combine inserting a vector of zeros into a vector of zeros just the larger...

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@312458 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/lib/Target/X86/X86ISelLowering.cpp b/lib/Target/X86/X86ISelLowering.cpp
index 0193f2bfd588925eb7067d97459d9a7847c25ee1..2cb6ec376c437719ba34ac797a5654dd55c63952 100644 (file)
--- a/lib/Target/X86/X86ISelLowering.cpp
+++ b/lib/Target/X86/X86ISelLowering.cpp
@@ -35656,6 +35656,11 @@ static SDValue combineInsertSubvector(SDNode *N, SelectionDAG &DAG,
   unsigned IdxVal = cast<ConstantSDNode>(Idx)->getZExtValue();
   MVT SubVecVT = SubVec.getSimpleValueType();
 
+  // Inserting zeros into zeros is a nop.
+  if (ISD::isBuildVectorAllZeros(Vec.getNode()) &&
+      ISD::isBuildVectorAllZeros(SubVec.getNode()))
+    return Vec;
+
   // If this is an insert of an extract, combine to a shuffle. Don't do this
   // if the insert or extract can be represented with a subregister operation.
   if (SubVec.getOpcode() == ISD::EXTRACT_SUBVECTOR &&

diff --git a/test/CodeGen/X86/avx512-intrinsics-fast-isel.ll b/test/CodeGen/X86/avx512-intrinsics-fast-isel.ll
index 18afae90ad9018dcd9ecc3beb5035e7a76d48a71..e5487ae2b101951c4a759fab4e8265fd663e45e4 100644 (file)
--- a/test/CodeGen/X86/avx512-intrinsics-fast-isel.ll
+++ b/test/CodeGen/X86/avx512-intrinsics-fast-isel.ll
@@ -1134,17 +1134,13 @@ define <8 x double> @test_mm512_zextpd128_pd512(<2 x double> %a0) nounwind {
 ; X32-LABEL: test_mm512_zextpd128_pd512:
 ; X32:       # BB#0:
 ; X32-NEXT:    vmovaps %xmm0, %xmm0
-; X32-NEXT:    vxorps %xmm1, %xmm1, %xmm1
-; X32-NEXT:    vmovaps %xmm1, %xmm1
-; X32-NEXT:    vinsertf64x4 $1, %ymm1, %zmm0, %zmm0
+; X32-NEXT:    vmovaps %ymm0, %ymm0
 ; X32-NEXT:    retl
 ;
 ; X64-LABEL: test_mm512_zextpd128_pd512:
 ; X64:       # BB#0:
 ; X64-NEXT:    vmovaps %xmm0, %xmm0
-; X64-NEXT:    vxorps %xmm1, %xmm1, %xmm1
-; X64-NEXT:    vmovaps %xmm1, %xmm1
-; X64-NEXT:    vinsertf64x4 $1, %ymm1, %zmm0, %zmm0
+; X64-NEXT:    vmovaps %ymm0, %ymm0
 ; X64-NEXT:    retq
   %res = shufflevector <2 x double> %a0, <2 x double> zeroinitializer, <8 x i32> <i32 0, i32 1, i32 2, i32 3, i32 2, i32 3, i32 2, i32 3>
   ret <8 x double> %res
@@ -1169,7 +1165,6 @@ define <16 x float> @test_mm512_zextps128_ps512(<4 x float> %a0) nounwind {
 ; X32:       # BB#0:
 ; X32-NEXT:    vmovaps %xmm0, %xmm0
 ; X32-NEXT:    vxorps %xmm1, %xmm1, %xmm1
-; X32-NEXT:    vmovaps %xmm1, %xmm1
 ; X32-NEXT:    vinsertf64x4 $1, %ymm1, %zmm0, %zmm0
 ; X32-NEXT:    retl
 ;
@@ -1177,7 +1172,6 @@ define <16 x float> @test_mm512_zextps128_ps512(<4 x float> %a0) nounwind {
 ; X64:       # BB#0:
 ; X64-NEXT:    vmovaps %xmm0, %xmm0
 ; X64-NEXT:    vxorps %xmm1, %xmm1, %xmm1
-; X64-NEXT:    vmovaps %xmm1, %xmm1
 ; X64-NEXT:    vinsertf64x4 $1, %ymm1, %zmm0, %zmm0
 ; X64-NEXT:    retq
   %res = shufflevector <4 x float> %a0, <4 x float> zeroinitializer, <16 x i32> <i32 0, i32 1, i32 2, i32 3, i32 4, i32 5, i32 6, i32 7, i32 4, i32 5, i32 6, i32 7, i32 4, i32 5, i32 6, i32 7>
@@ -1202,17 +1196,13 @@ define <8 x i64> @test_mm512_zextsi128_si512(<2 x i64> %a0) nounwind {
 ; X32-LABEL: test_mm512_zextsi128_si512:
 ; X32:       # BB#0:
 ; X32-NEXT:    vmovaps %xmm0, %xmm0
-; X32-NEXT:    vxorps %xmm1, %xmm1, %xmm1
-; X32-NEXT:    vmovaps %xmm1, %xmm1
-; X32-NEXT:    vinsertf64x4 $1, %ymm1, %zmm0, %zmm0
+; X32-NEXT:    vmovaps %ymm0, %ymm0
 ; X32-NEXT:    retl
 ;
 ; X64-LABEL: test_mm512_zextsi128_si512:
 ; X64:       # BB#0:
 ; X64-NEXT:    vmovaps %xmm0, %xmm0
-; X64-NEXT:    vxorps %xmm1, %xmm1, %xmm1
-; X64-NEXT:    vmovaps %xmm1, %xmm1
-; X64-NEXT:    vinsertf64x4 $1, %ymm1, %zmm0, %zmm0
+; X64-NEXT:    vmovaps %ymm0, %ymm0
 ; X64-NEXT:    retq
   %res = shufflevector <2 x i64> %a0, <2 x i64> zeroinitializer, <8 x i32> <i32 0, i32 1, i32 2, i32 3, i32 2, i32 3, i32 2, i32 3>
   ret <8 x i64> %res