[release_36] Cherry-pick r232085.

Original commit message:
[X86] Fix a regression introduced by r223641.
The permps and permd instructions have their operands swapped compared to the
intrinsic definition. Therefore, they do not fall into the INTR_TYPE_2OP
category.

I did not create a new category for those two, as they are the only one AFAICT
in that case.

<rdar://problem/20108262>


git-svn-id: https://llvm.org/svn/llvm-project/llvm/branches/release_36@232118 91177308-0d34-0410-b5e6-96231b3b80d8

lib/Target/X86/X86ISelLowering.cpp

@@ -17172,6 +17172,13 @@ static SDValue LowerINTRINSIC_WO_CHAIN(SDValue Op, const X86Subtarget *Subtarget
   switch (IntNo) {
   default: return SDValue();    // Don't custom lower most intrinsics.
 
+  case Intrinsic::x86_avx2_permd:
+  case Intrinsic::x86_avx2_permps:
+    // Operands intentionally swapped. Mask is last operand to intrinsic,
+    // but second operand for node/instruction.
+    return DAG.getNode(X86ISD::VPERMV, dl, Op.getValueType(),
+                       Op.getOperand(2), Op.getOperand(1));
+
   case Intrinsic::x86_avx512_mask_valign_q_512:
   case Intrinsic::x86_avx512_mask_valign_d_512:
     // Vector source operands are swapped.

lib/Target/X86/X86IntrinsicsInfo.h

@@ -175,8 +175,6 @@ static const IntrinsicData  IntrinsicsWithoutChain[] = {
   X86_INTRINSIC_DATA(avx2_packsswb,     INTR_TYPE_2OP, X86ISD::PACKSS, 0),
   X86_INTRINSIC_DATA(avx2_packusdw,     INTR_TYPE_2OP, X86ISD::PACKUS, 0),
   X86_INTRINSIC_DATA(avx2_packuswb,     INTR_TYPE_2OP, X86ISD::PACKUS, 0),
-  X86_INTRINSIC_DATA(avx2_permd,        INTR_TYPE_2OP, X86ISD::VPERMV, 0),
-  X86_INTRINSIC_DATA(avx2_permps,       INTR_TYPE_2OP, X86ISD::VPERMV, 0),
   X86_INTRINSIC_DATA(avx2_phadd_d,      INTR_TYPE_2OP, X86ISD::HADD, 0),
   X86_INTRINSIC_DATA(avx2_phadd_w,      INTR_TYPE_2OP, X86ISD::HADD, 0),
   X86_INTRINSIC_DATA(avx2_phsub_d,      INTR_TYPE_2OP, X86ISD::HSUB, 0),

test/CodeGen/X86/avx2-intrinsics-x86.ll

@@ -785,7 +785,10 @@ declare <4 x i64> @llvm.x86.avx2.pbroadcastq.256(<2 x i64>) nounwind readonly
 
 
 define <8 x i32> @test_x86_avx2_permd(<8 x i32> %a0, <8 x i32> %a1) {
-  ; CHECK: vpermd
+  ; Check that the arguments are swapped between the intrinsic definition
+  ; and its lowering. Indeed, the offsets are the first source in
+  ; the instruction.
+  ; CHECK: vpermd %ymm0, %ymm1, %ymm0
   %res = call <8 x i32> @llvm.x86.avx2.permd(<8 x i32> %a0, <8 x i32> %a1) ; <<8 x i32>> [#uses=1]
   ret <8 x i32> %res
 }
@@ -793,7 +796,10 @@ declare <8 x i32> @llvm.x86.avx2.permd(<8 x i32>, <8 x i32>) nounwind readonly
 
 
 define <8 x float> @test_x86_avx2_permps(<8 x float> %a0, <8 x float> %a1) {
-  ; CHECK: vpermps
+  ; Check that the arguments are swapped between the intrinsic definition
+  ; and its lowering. Indeed, the offsets are the first source in
+  ; the instruction.
+  ; CHECK: vpermps %ymm0, %ymm1, %ymm0
   %res = call <8 x float> @llvm.x86.avx2.permps(<8 x float> %a0, <8 x float> %a1) ; <<8 x float>> [#uses=1]
   ret <8 x float> %res
 }