[AVX512] Don't create SHRUNKBLEND SDNodes for 512-bit vectors

There are no 512-bit blend instructions so we shouldn't create SHRUNKBLEND for them.

On a side note, it looks like there may be a missed opportunity for constant folding TESTM when LHS and RHS are equal.

This fixes PR34139.

Differential Revision: https://reviews.llvm.org/D36992

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@311572 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/lib/Target/X86/X86ISelLowering.cpp b/lib/Target/X86/X86ISelLowering.cpp
index bd56edd59967cd7943119edb9fb75d92331bca5d..d406fef3eaccd2742cc6fcaba7ce1e7d07433cfa 100644 (file)
--- a/lib/Target/X86/X86ISelLowering.cpp
+++ b/lib/Target/X86/X86ISelLowering.cpp
@@ -30628,6 +30628,9 @@ static SDValue combineSelect(SDNode *N, SelectionDAG &DAG,
     // Byte blends are only available in AVX2
     if (VT == MVT::v32i8 && !Subtarget.hasAVX2())
       return SDValue();
+    // There are no 512-bit blend instructions that use sign bits.
+    if (VT.is512BitVector())
+      return SDValue();
 
     assert(BitWidth >= 8 && BitWidth <= 64 && "Invalid mask size");
     APInt DemandedMask(APInt::getSignMask(BitWidth));

diff --git a/test/CodeGen/X86/pr34139.ll b/test/CodeGen/X86/pr34139.ll
new file mode 100644 (file)
index 0000000..c20c2cd
--- /dev/null
+++ b/test/CodeGen/X86/pr34139.ll
@@ -0,0 +1,24 @@
+; NOTE: Assertions have been autogenerated by utils/update_llc_test_checks.py
+; RUN: llc < %s -mtriple=x86_64-unknown-linux-gnu -mcpu=knl | FileCheck %s
+
+define void @f_f(<16 x double>* %ptr) {
+; CHECK-LABEL: f_f:
+; CHECK:       # BB#0:
+; CHECK-NEXT:    vpcmpeqd %xmm0, %xmm0, %xmm0
+; CHECK-NEXT:    vmovdqa %xmm0, (%rax)
+; CHECK-NEXT:    vpternlogd $255, %zmm0, %zmm0, %zmm0
+; CHECK-NEXT:    vmovapd (%rdi), %zmm1
+; CHECK-NEXT:    vmovapd 64(%rdi), %zmm2
+; CHECK-NEXT:    vptestmq %zmm0, %zmm0, %k1
+; CHECK-NEXT:    vmovapd %zmm0, %zmm1 {%k1}
+; CHECK-NEXT:    vmovapd %zmm0, %zmm2 {%k1}
+; CHECK-NEXT:    vmovapd %zmm2, 64(%rdi)
+; CHECK-NEXT:    vmovapd %zmm1, (%rdi)
+  store <16 x i8> <i8 -1, i8 -1, i8 -1, i8 -1, i8 -1, i8 -1, i8 -1, i8 -1, i8 -1, i8 -1, i8 -1, i8 -1, i8 -1, i8 -1, i8 -1, i8 -1>, <16 x i8>* undef
+  %load_mask8.i.i.i = load <16 x i8>, <16 x i8>* undef
+  %v.i.i.i.i = load <16 x double>, <16 x double>* %ptr
+  %mask_vec_i1.i.i.i51.i.i = icmp ne <16 x i8> %load_mask8.i.i.i, zeroinitializer
+  %v1.i.i.i.i = select <16 x i1> %mask_vec_i1.i.i.i51.i.i, <16 x double> undef, <16 x double> %v.i.i.i.i
+  store <16 x double> %v1.i.i.i.i, <16 x double>* %ptr
+  unreachable
+}