[llvm] r198730 - Fix a bug about generating undef operand when optimising shuffle vector and insert element in instruction combine.

[Hao Liu]

Author: haoliu
Date: Tue Jan  7 21:06:15 2014
New Revision: 198730

URL: http://llvm.org/viewvc/llvm-project?rev=198730&view=rev
Log:
Fix a bug about generating undef operand when optimising shuffle vector and insert element in instruction combine.

Modified:
    llvm/trunk/lib/Transforms/InstCombine/InstCombineVectorOps.cpp
    llvm/trunk/test/Transforms/InstCombine/vec_shuffle.ll

Modified: llvm/trunk/lib/Transforms/InstCombine/InstCombineVectorOps.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/InstCombine/InstCombineVectorOps.cpp?rev=198730&r1=198729&r2=198730&view=diff
==============================================================================
--- llvm/trunk/lib/Transforms/InstCombine/InstCombineVectorOps.cpp (original)
+++ llvm/trunk/lib/Transforms/InstCombine/InstCombineVectorOps.cpp Tue Jan  7 21:06:15 2014
@@ -763,9 +763,10 @@ InstCombiner::EvaluateInDifferentElement
         }
       }
 
+      // If element is not in Mask, no need to handle the operand 1 (element to
+      // be inserted). Just evaluate values in operand 0 according to Mask.
       if (!Found)
-        return UndefValue::get(
-            VectorType::get(V->getType()->getScalarType(), Mask.size()));
+        return EvaluateInDifferentElementOrder(I->getOperand(0), Mask);
 
       Value *V = EvaluateInDifferentElementOrder(I->getOperand(0), Mask);
       return InsertElementInst::Create(V, I->getOperand(1),

Modified: llvm/trunk/test/Transforms/InstCombine/vec_shuffle.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/InstCombine/vec_shuffle.ll?rev=198730&r1=198729&r2=198730&view=diff
==============================================================================
--- llvm/trunk/test/Transforms/InstCombine/vec_shuffle.ll (original)
+++ llvm/trunk/test/Transforms/InstCombine/vec_shuffle.ll Tue Jan  7 21:06:15 2014
@@ -228,3 +228,20 @@ define <4 x float> @test15b(<4 x float>
   ret <4 x float> %tmp5
 }
 
+define <1 x i32> @test16a(i32 %ele) {
+; CHECK-LABEL: @test16a(
+; CHECK-NEXT: ret <1 x i32> <i32 2>
+  %tmp0 = insertelement <2 x i32> <i32 1, i32 undef>, i32 %ele, i32 1
+  %tmp1 = shl <2 x i32> %tmp0, <i32 1, i32 1>
+  %tmp2 = shufflevector <2 x i32> %tmp1, <2 x i32> undef, <1 x i32> <i32 0>
+  ret <1 x i32> %tmp2
+}
+
+define <4 x i8> @test16b(i8 %ele) {
+; CHECK-LABEL: @test16b(
+; CHECK-NEXT: ret <4 x i8> <i8 2, i8 2, i8 2, i8 2>
+  %tmp0 = insertelement <8 x i8> <i8 1, i8 1, i8 1, i8 1, i8 1, i8 1, i8 undef, i8 1>, i8 %ele, i32 6
+  %tmp1 = shl <8 x i8> %tmp0, <i8 1, i8 1, i8 1, i8 1, i8 1, i8 1, i8 1, i8 1>
+  %tmp2 = shufflevector <8 x i8> %tmp1, <8 x i8> undef, <4 x i32> <i32 1, i32 2, i32 3, i32 4>
+  ret <4 x i8> %tmp2
+}
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