[InstCombine] fix crash while trying to narrow a binop of shuffles (PR40734)

https://bugs.llvm.org/show_bug.cgi?id=40734

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@354144 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/lib/Transforms/InstCombine/InstructionCombining.cpp b/lib/Transforms/InstCombine/InstructionCombining.cpp
index 8cbf57a97ef7e8d86ac26280bf904ab718d8fbdc..723bb4c0d68988b83bf1f0224e490bcc9ae0050f 100644 (file)
--- a/lib/Transforms/InstCombine/InstructionCombining.cpp
+++ b/lib/Transforms/InstCombine/InstructionCombining.cpp
@@ -1375,7 +1375,8 @@ Instruction *InstCombiner::foldVectorBinop(BinaryOperator &Inst) {
   if (match(LHS, m_ShuffleVector(m_Value(L0), m_Value(L1), m_Constant(Mask))) &&
       match(RHS, m_ShuffleVector(m_Value(R0), m_Value(R1), m_Specific(Mask))) &&
       LHS->hasOneUse() && RHS->hasOneUse() &&
-      cast<ShuffleVectorInst>(LHS)->isConcat()) {
+      cast<ShuffleVectorInst>(LHS)->isConcat() &&
+      cast<ShuffleVectorInst>(RHS)->isConcat()) {
     // This transform does not have the speculative execution constraint as
     // below because the shuffle is a concatenation. The new binops are
     // operating on exactly the same elements as the existing binop.

diff --git a/test/Transforms/InstCombine/vec_shuffle.ll b/test/Transforms/InstCombine/vec_shuffle.ll
index aae337d0de3f8d12db38df2422a9ef8e361191b7..354256aab54fa0526bec570e3358656fdc47539c 100644 (file)
--- a/test/Transforms/InstCombine/vec_shuffle.ll
+++ b/test/Transforms/InstCombine/vec_shuffle.ll
@@ -1125,3 +1125,18 @@ define <2 x float> @frem_splat_constant1(<2 x float> %x) {
   ret <2 x float> %r
 }
 
+; Equivalent shuffle masks, but only one is a narrowing op.
+
+define <2 x i1> @PR40734(<1 x i1> %x, <4 x i1> %y) {
+; CHECK-LABEL: @PR40734(
+; CHECK-NEXT:    [[WIDEN:%.*]] = shufflevector <1 x i1> zeroinitializer, <1 x i1> [[X:%.*]], <2 x i32> <i32 0, i32 1>
+; CHECK-NEXT:    [[NARROW:%.*]] = shufflevector <4 x i1> [[Y:%.*]], <4 x i1> undef, <2 x i32> <i32 0, i32 1>
+; CHECK-NEXT:    [[R:%.*]] = and <2 x i1> [[WIDEN]], [[NARROW]]
+; CHECK-NEXT:    ret <2 x i1> [[R]]
+;
+  %widen = shufflevector <1 x i1> zeroinitializer, <1 x i1> %x, <2 x i32> <i32 0, i32 1>
+  %narrow = shufflevector <4 x i1> %y, <4 x i1> undef, <2 x i32> <i32 0, i32 1>
+  %r = and <2 x i1> %widen, %narrow
+  ret <2 x i1> %r
+}
+