[PowerPC] Emit VMX loads/stores for aligned ops to avoid adding swaps on LE

Fixes PR30730.
This is a re-commit of a pulled commit. The commit was pulled because some
software projects contained uses of Altivec vectors that violated alignment
requirements. Known issues have now been fixed.

Committing on behalf of Lei Huang.

Differential Revision: https://reviews.llvm.org/D26861

llvm-svn: 301892

2 files changed, 23 insertions, 6 deletions

diff --git a/llvm/lib/Target/PowerPC/PPCISelLowering.cpp b/llvm/lib/Target/PowerPC/PPCISelLowering.cpp
index b3a611d37c9..483e9b171d5 100644
--- a/llvm/lib/Target/PowerPC/PPCISelLowering.cpp
+++ b/llvm/lib/Target/PowerPC/PPCISelLowering.cpp
@@ -11213,6 +11213,14 @@ SDValue PPCTargetLowering::expandVSXLoadForLE(SDNode *N,
   }
 
   MVT VecTy = N->getValueType(0).getSimpleVT();
+
+  // Do not expand to PPCISD::LXVD2X + PPCISD::XXSWAPD when the load is
+  // aligned and the type is a vector with elements up to 4 bytes
+  if (Subtarget.needsSwapsForVSXMemOps() && !(MMO->getAlignment()%16)
+      && VecTy.getScalarSizeInBits() <= 32 ) {
+    return SDValue();
+  }
+
   SDValue LoadOps[] = { Chain, Base };
   SDValue Load = DAG.getMemIntrinsicNode(PPCISD::LXVD2X, dl,
                                          DAG.getVTList(MVT::v2f64, MVT::Other),
@@ -11277,6 +11285,13 @@ SDValue PPCTargetLowering::expandVSXStoreForLE(SDNode *N,
   SDValue Src = N->getOperand(SrcOpnd);
   MVT VecTy = Src.getValueType().getSimpleVT();
 
+  // Do not expand to PPCISD::XXSWAPD and PPCISD::STXVD2X when the load is
+  // aligned and the type is a vector with elements up to 4 bytes
+  if (Subtarget.needsSwapsForVSXMemOps() && !(MMO->getAlignment()%16)
+      && VecTy.getScalarSizeInBits() <= 32 ) {
+    return SDValue();
+  }
+
   // All stores are done as v2f64 and possible bit cast.
   if (VecTy != MVT::v2f64) {
     Src = DAG.getNode(ISD::BITCAST, dl, MVT::v2f64, Src);
diff --git a/llvm/lib/Target/PowerPC/PPCInstrVSX.td b/llvm/lib/Target/PowerPC/PPCInstrVSX.td
index 13603732397..967557452f2 100644
--- a/llvm/lib/Target/PowerPC/PPCInstrVSX.td
+++ b/llvm/lib/Target/PowerPC/PPCInstrVSX.td
@@ -138,7 +138,7 @@ let Uses = [RM] in {
     def LXVW4X : XX1Form<31, 780,
                          (outs vsrc:$XT), (ins memrr:$src),
                          "lxvw4x $XT, $src", IIC_LdStLFD,
-                         [(set v4i32:$XT, (int_ppc_vsx_lxvw4x xoaddr:$src))]>;
+                         []>;
   } // mayLoad
 
   // Store indexed instructions
@@ -160,7 +160,7 @@ let Uses = [RM] in {
     def STXVW4X : XX1Form<31, 908,
                          (outs), (ins vsrc:$XT, memrr:$dst),
                          "stxvw4x $XT, $dst", IIC_LdStSTFD,
-                         [(store v4i32:$XT, xoaddr:$dst)]>;
+                         []>;
     }
   } // mayStore
 
@@ -1041,8 +1041,6 @@ let Predicates = [HasVSX, HasOnlySwappingMemOps] in {
   // Stores.
   def : Pat<(int_ppc_vsx_stxvd2x v2f64:$rS, xoaddr:$dst),
             (STXVD2X $rS, xoaddr:$dst)>;
-  def : Pat<(int_ppc_vsx_stxvw4x v4i32:$rS, xoaddr:$dst),
-            (STXVW4X $rS, xoaddr:$dst)>;
   def : Pat<(int_ppc_vsx_stxvd2x_be v2f64:$rS, xoaddr:$dst),
             (STXVD2X $rS, xoaddr:$dst)>;
   def : Pat<(int_ppc_vsx_stxvw4x_be v4i32:$rS, xoaddr:$dst),
@@ -1053,8 +1051,12 @@ let Predicates = [IsBigEndian, HasVSX, HasOnlySwappingMemOps] in {
   def : Pat<(v2f64 (load xoaddr:$src)), (LXVD2X xoaddr:$src)>;
   def : Pat<(v2i64 (load xoaddr:$src)), (LXVD2X xoaddr:$src)>;
   def : Pat<(v4i32 (load xoaddr:$src)), (LXVW4X xoaddr:$src)>;
+  def : Pat<(v4i32 (int_ppc_vsx_lxvw4x xoaddr:$src)), (LXVW4X xoaddr:$src)>;
   def : Pat<(store v2f64:$rS, xoaddr:$dst), (STXVD2X $rS, xoaddr:$dst)>;
   def : Pat<(store v2i64:$rS, xoaddr:$dst), (STXVD2X $rS, xoaddr:$dst)>;
+  def : Pat<(store v4i32:$XT, xoaddr:$dst), (STXVW4X $XT, xoaddr:$dst)>;
+  def : Pat<(int_ppc_vsx_stxvw4x v4i32:$rS, xoaddr:$dst),
+            (STXVW4X $rS, xoaddr:$dst)>;
 }
 
 // Permutes.
@@ -1890,8 +1892,8 @@ let Predicates = [IsLittleEndian, HasVSX] in
   def : Pat<(f64 (vector_extract v2f64:$S, i64:$Idx)),
             (f64 VectorExtractions.LE_VARIABLE_DOUBLE)>;
 
-  def : Pat<(v4i32 (int_ppc_vsx_lxvw4x_be xoaddr:$src)), (LXVW4X xoaddr:$src)>;
-  def : Pat<(v2f64 (int_ppc_vsx_lxvd2x_be xoaddr:$src)), (LXVD2X xoaddr:$src)>;
+def : Pat<(v4i32 (int_ppc_vsx_lxvw4x_be xoaddr:$src)), (LXVW4X xoaddr:$src)>;
+def : Pat<(v2f64 (int_ppc_vsx_lxvd2x_be xoaddr:$src)), (LXVD2X xoaddr:$src)>;
 
 let Predicates = [IsLittleEndian, HasDirectMove] in {
   // v16i8 scalar <-> vector conversions (LE)