[PowerPC] Don't always consider P8Altivec-only masks in LowerVECTOR_SHUFFLE

LowerVECTOR_SHUFFLE needs to decide whether to pass a vector shuffle off to the
TableGen-generated matching code, and it does this by testing the same
predicates used by the TableGen files. Unfortunately, when we added new
P8Altivec-only predicates, we started universally testing them in
LowerVECTOR_SHUFFLE, and if then matched when targeting a system prior to a P8,
we'd end up with a selection failure.

llvm-svn: 246675

2 files changed, 36 insertions, 6 deletions

diff --git a/llvm/lib/Target/PowerPC/PPCISelLowering.cpp b/llvm/lib/Target/PowerPC/PPCISelLowering.cpp
index 2480c65b9ed..40a80d62113 100644
--- a/llvm/lib/Target/PowerPC/PPCISelLowering.cpp
+++ b/llvm/lib/Target/PowerPC/PPCISelLowering.cpp
@@ -7200,7 +7200,6 @@ SDValue PPCTargetLowering::LowerVECTOR_SHUFFLE(SDValue Op,
         PPC::isSplatShuffleMask(SVOp, 4) ||
         PPC::isVPKUWUMShuffleMask(SVOp, 1, DAG) ||
         PPC::isVPKUHUMShuffleMask(SVOp, 1, DAG) ||
-        PPC::isVPKUDUMShuffleMask(SVOp, 1, DAG) ||
         PPC::isVSLDOIShuffleMask(SVOp, 1, DAG) != -1 ||
         PPC::isVMRGLShuffleMask(SVOp, 1, 1, DAG) ||
         PPC::isVMRGLShuffleMask(SVOp, 2, 1, DAG) ||
@@ -7208,8 +7207,10 @@ SDValue PPCTargetLowering::LowerVECTOR_SHUFFLE(SDValue Op,
         PPC::isVMRGHShuffleMask(SVOp, 1, 1, DAG) ||
         PPC::isVMRGHShuffleMask(SVOp, 2, 1, DAG) ||
         PPC::isVMRGHShuffleMask(SVOp, 4, 1, DAG) ||
-        PPC::isVMRGEOShuffleMask(SVOp, true, 1, DAG)   ||
-        PPC::isVMRGEOShuffleMask(SVOp, false, 1, DAG)) {
+        (Subtarget.hasP8Altivec() && (
+         PPC::isVPKUDUMShuffleMask(SVOp, 1, DAG) ||
+         PPC::isVMRGEOShuffleMask(SVOp, true, 1, DAG) ||
+         PPC::isVMRGEOShuffleMask(SVOp, false, 1, DAG)))) {
       return Op;
     }
   }
@@ -7220,7 +7221,6 @@ SDValue PPCTargetLowering::LowerVECTOR_SHUFFLE(SDValue Op,
   unsigned int ShuffleKind = isLittleEndian ? 2 : 0;
   if (PPC::isVPKUWUMShuffleMask(SVOp, ShuffleKind, DAG) ||
       PPC::isVPKUHUMShuffleMask(SVOp, ShuffleKind, DAG) ||
-      PPC::isVPKUDUMShuffleMask(SVOp, ShuffleKind, DAG) ||
       PPC::isVSLDOIShuffleMask(SVOp, ShuffleKind, DAG) != -1 ||
       PPC::isVMRGLShuffleMask(SVOp, 1, ShuffleKind, DAG) ||
       PPC::isVMRGLShuffleMask(SVOp, 2, ShuffleKind, DAG) ||
@@ -7228,8 +7228,10 @@ SDValue PPCTargetLowering::LowerVECTOR_SHUFFLE(SDValue Op,
       PPC::isVMRGHShuffleMask(SVOp, 1, ShuffleKind, DAG) ||
       PPC::isVMRGHShuffleMask(SVOp, 2, ShuffleKind, DAG) ||
       PPC::isVMRGHShuffleMask(SVOp, 4, ShuffleKind, DAG) ||
-      PPC::isVMRGEOShuffleMask(SVOp, true, ShuffleKind, DAG)             ||
-      PPC::isVMRGEOShuffleMask(SVOp, false, ShuffleKind, DAG))
+      (Subtarget.hasP8Altivec() && (
+       PPC::isVPKUDUMShuffleMask(SVOp, ShuffleKind, DAG) ||
+       PPC::isVMRGEOShuffleMask(SVOp, true, ShuffleKind, DAG) ||
+       PPC::isVMRGEOShuffleMask(SVOp, false, ShuffleKind, DAG))))
     return Op;
 
   // Check to see if this is a shuffle of 4-byte values.  If so, we can use our
diff --git a/llvm/test/CodeGen/PowerPC/p8altivec-shuffles-pred.ll b/llvm/test/CodeGen/PowerPC/p8altivec-shuffles-pred.ll
new file mode 100644
index 00000000000..052f55644fe
--- /dev/null
+++ b/llvm/test/CodeGen/PowerPC/p8altivec-shuffles-pred.ll
@@ -0,0 +1,28 @@
+; RUN: llc < %s | FileCheck %s
+target datalayout = "E-m:e-i64:64-n32:64"
+target triple = "powerpc64-unknown-linux-gnu"
+
+; Function Attrs: nounwind
+define <2 x i32> @test1(<4 x i32> %wide.vec) #0 {
+entry:
+  %strided.vec = shufflevector <4 x i32> %wide.vec, <4 x i32> undef, <2 x i32> <i32 0, i32 2>
+  ret <2 x i32> %strided.vec
+
+; CHECK-LABEL: @test1
+; CHECK: vsldoi 2, 2, 2, 12
+; CHECK: blr
+}
+
+; Function Attrs: nounwind
+define <16 x i8> @test2(<16 x i8> %wide.vec) #0 {
+entry:
+  %strided.vec = shufflevector <16 x i8> %wide.vec, <16 x i8> undef, <16 x i32> <i32 undef, i32 undef, i32 undef, i32 undef, i32 0, i32 1, i32 2, i32 3, i32 undef, i32 undef, i32 undef, i32 undef, i32 8, i32 9, i32 10, i32 11>
+  ret <16 x i8> %strided.vec
+
+; CHECK-LABEL: @test2
+; CHECK: vsldoi 2, 2, 2, 12
+; CHECK: blr
+}
+
+attributes #0 = { nounwind "target-cpu"="pwr7" }
+