From: Elad Cohen <elad2.cohen@intel.com>
Date: Mon, 14 Aug 2017 10:49:45 +0000 (+0000)
Subject: [SelectionDAG] combine vextract (v1iX extract_subvector(vNiX, Idx))
X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=dbcaf5914243123ccf4f9dddd061466f4982ccf6;p=llvm

[SelectionDAG] combine vextract (v1iX extract_subvector(vNiX, Idx))
into vextract(vNiX,Idx) when creating vextract with getNode().
This case appeared in AVX512 after fixing pr33349 in r310552.

Differential revision: https://reviews.llvm.org/D36571

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@310828 91177308-0d34-0410-b5e6-96231b3b80d8
---

diff --git a/lib/CodeGen/SelectionDAG/SelectionDAG.cpp b/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
index b37704946a0..0ef8adaabbb 100644
--- a/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
+++ b/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
@@ -4373,6 +4373,15 @@ SDValue SelectionDAG::getNode(unsigned Opcode, const SDLoc &DL, EVT VT,
         return getNode(ISD::EXTRACT_VECTOR_ELT, DL, VT, N1.getOperand(0), N2);
       }
     }
+
+    // EXTRACT_VECTOR_ELT of v1iX EXTRACT_SUBVECTOR could be formed
+    // when vector types are scalarized and v1iX is legal.
+    // vextract (v1iX extract_subvector(vNiX, Idx)) -> vextract(vNiX,Idx)
+    if (N1.getOpcode() == ISD::EXTRACT_SUBVECTOR &&
+        N1.getValueType().getVectorNumElements() == 1) {
+      return getNode(ISD::EXTRACT_VECTOR_ELT, DL, VT, N1.getOperand(0),
+                     N1.getOperand(1));
+    }
     break;
   case ISD::EXTRACT_ELEMENT:
     assert(N2C && (unsigned)N2C->getZExtValue() < 2 && "Bad EXTRACT_ELEMENT!");
diff --git a/test/CodeGen/X86/pr33349.ll b/test/CodeGen/X86/pr33349.ll
index db866db2248..e73d1f590c1 100644
--- a/test/CodeGen/X86/pr33349.ll
+++ b/test/CodeGen/X86/pr33349.ll
@@ -43,8 +43,6 @@ target triple = "x86_64-unknown-linux-gnu"
 ; SKX-NEXT:    kshiftrw $2, %k0, %k1
 ; SKX-NEXT:    kshiftlw $15, %k1, %k2
 ; SKX-NEXT:    kshiftrw $15, %k2, %k2
-; SKX-NEXT:    kshiftlw $15, %k2, %k2
-; SKX-NEXT:    kshiftrw $15, %k2, %k2
 ; SKX-NEXT:    kmovd %k2, %eax
 ; SKX-NEXT:    testb $1, %al
 ; SKX-NEXT:    fld1
@@ -53,24 +51,18 @@ target triple = "x86_64-unknown-linux-gnu"
 ; SKX-NEXT:    fcmovne %st(2), %st(0)
 ; SKX-NEXT:    kshiftlw $14, %k1, %k1
 ; SKX-NEXT:    kshiftrw $15, %k1, %k1
-; SKX-NEXT:    kshiftlw $15, %k1, %k1
-; SKX-NEXT:    kshiftrw $15, %k1, %k1
 ; SKX-NEXT:    kmovd %k1, %eax
 ; SKX-NEXT:    testb $1, %al
 ; SKX-NEXT:    fld %st(1)
 ; SKX-NEXT:    fcmovne %st(3), %st(0)
 ; SKX-NEXT:    kshiftlw $15, %k0, %k1
 ; SKX-NEXT:    kshiftrw $15, %k1, %k1
-; SKX-NEXT:    kshiftlw $15, %k1, %k1
-; SKX-NEXT:    kshiftrw $15, %k1, %k1
 ; SKX-NEXT:    kmovd %k1, %eax
 ; SKX-NEXT:    testb $1, %al
 ; SKX-NEXT:    fld %st(2)
 ; SKX-NEXT:    fcmovne %st(4), %st(0)
 ; SKX-NEXT:    kshiftlw $14, %k0, %k0
 ; SKX-NEXT:    kshiftrw $15, %k0, %k0
-; SKX-NEXT:    kshiftlw $15, %k0, %k0
-; SKX-NEXT:    kshiftrw $15, %k0, %k0
 ; SKX-NEXT:    kmovd %k0, %eax
 ; SKX-NEXT:    testb $1, %al
 ; SKX-NEXT:    fxch %st(3)