[llvm] r297166 - revert r297155 because there's a clang test that depends on InstCombine:

[Sanjay Patel via llvm-commits]

Author: spatel
Date: Tue Mar  7 11:41:45 2017
New Revision: 297166

URL: http://llvm.org/viewvc/llvm-project?rev=297166&view=rev
Log:
revert r297155 because there's a clang test that depends on InstCombine:

tools/clang/test/CodeGen/zvector.c


Modified:
    llvm/trunk/lib/Transforms/InstCombine/InstCombineCasts.cpp
    llvm/trunk/test/Transforms/InstCombine/trunc.ll

Modified: llvm/trunk/lib/Transforms/InstCombine/InstCombineCasts.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/InstCombine/InstCombineCasts.cpp?rev=297166&r1=297165&r2=297166&view=diff
==============================================================================
--- llvm/trunk/lib/Transforms/InstCombine/InstCombineCasts.cpp (original)
+++ llvm/trunk/lib/Transforms/InstCombine/InstCombineCasts.cpp Tue Mar  7 11:41:45 2017
@@ -463,23 +463,6 @@ Instruction *InstCombiner::shrinkBitwise
   return BinaryOperator::Create(LogicOp->getOpcode(), NarrowOp0, NarrowC);
 }
 
-/// Try to narrow the width of a splat shuffle. This could be generalized to any
-/// shuffle with a constant operand, but we limit the transform to avoid
-/// creating a shuffle type that targets may not be able to lower effectively.
-static Instruction *shrinkSplatShuffle(TruncInst &Trunc,
-                                       InstCombiner::BuilderTy &Builder) {
-  auto *Shuf = dyn_cast<ShuffleVectorInst>(Trunc.getOperand(0));
-  if (Shuf && Shuf->hasOneUse() && isa<UndefValue>(Shuf->getOperand(1)) &&
-      Shuf->getMask()->getSplatValue()) {
-    // trunc (shuf X, Undef, SplatMask) --> shuf (trunc X), Undef, SplatMask
-    Constant *NarrowUndef = UndefValue::get(Trunc.getType());
-    Value *NarrowOp = Builder.CreateTrunc(Shuf->getOperand(0), Trunc.getType());
-    return new ShuffleVectorInst(NarrowOp, NarrowUndef, Shuf->getMask());
-  }
-
-  return nullptr;
-}
-
 Instruction *InstCombiner::visitTrunc(TruncInst &CI) {
   if (Instruction *Result = commonCastTransforms(CI))
     return Result;
@@ -571,9 +554,6 @@ Instruction *InstCombiner::visitTrunc(Tr
   if (Instruction *I = shrinkBitwiseLogic(CI))
     return I;
 
-  if (Instruction *I = shrinkSplatShuffle(CI, *Builder))
-    return I;
-
   if (Src->hasOneUse() && isa<IntegerType>(SrcTy) &&
       shouldChangeType(SrcTy, DestTy)) {
     // Transform "trunc (shl X, cst)" -> "shl (trunc X), cst" so long as the

Modified: llvm/trunk/test/Transforms/InstCombine/trunc.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/InstCombine/trunc.ll?rev=297166&r1=297165&r2=297166&view=diff
==============================================================================
--- llvm/trunk/test/Transforms/InstCombine/trunc.ll (original)
+++ llvm/trunk/test/Transforms/InstCombine/trunc.ll Tue Mar  7 11:41:45 2017
@@ -478,12 +478,13 @@ define <4 x i8> @wide_shuf(<4 x i32> %x)
   ret <4 x i8> %trunc
 }
 
+; FIXME:
 ; trunc (shuffle X, undef, SplatMask) --> shuffle (trunc X), undef, SplatMask
 
 define <4 x i8> @wide_splat1(<4 x i32> %x) {
 ; CHECK-LABEL: @wide_splat1(
-; CHECK-NEXT:    [[TMP1:%.*]] = trunc <4 x i32> %x to <4 x i8>
-; CHECK-NEXT:    [[TRUNC:%.*]] = shufflevector <4 x i8> [[TMP1]], <4 x i8> undef, <4 x i32> <i32 2, i32 2, i32 2, i32 2>
+; CHECK-NEXT:    [[SHUF:%.*]] = shufflevector <4 x i32> %x, <4 x i32> undef, <4 x i32> <i32 2, i32 2, i32 2, i32 2>
+; CHECK-NEXT:    [[TRUNC:%.*]] = trunc <4 x i32> [[SHUF]] to <4 x i8>
 ; CHECK-NEXT:    ret <4 x i8> [[TRUNC]]
 ;
   %shuf = shufflevector <4 x i32> %x, <4 x i32> undef, <4 x i32> <i32 2, i32 2, i32 2, i32 2>
@@ -491,13 +492,14 @@ define <4 x i8> @wide_splat1(<4 x i32> %
   ret <4 x i8> %trunc
 }
 
+; FIXME:
 ; Test weird types.
 ; trunc (shuffle X, undef, SplatMask) --> shuffle (trunc X), undef, SplatMask
 
 define <3 x i31> @wide_splat2(<3 x i33> %x) {
 ; CHECK-LABEL: @wide_splat2(
-; CHECK-NEXT:    [[TMP1:%.*]] = trunc <3 x i33> %x to <3 x i31>
-; CHECK-NEXT:    [[TRUNC:%.*]] = shufflevector <3 x i31> [[TMP1]], <3 x i31> undef, <3 x i32> <i32 1, i32 1, i32 1>
+; CHECK-NEXT:    [[SHUF:%.*]] = shufflevector <3 x i33> %x, <3 x i33> undef, <3 x i32> <i32 1, i32 1, i32 1>
+; CHECK-NEXT:    [[TRUNC:%.*]] = trunc <3 x i33> [[SHUF]] to <3 x i31>
 ; CHECK-NEXT:    ret <3 x i31> [[TRUNC]]
 ;
   %shuf = shufflevector <3 x i33> %x, <3 x i33> undef, <3 x i32> <i32 1, i32 1, i32 1>