[PATCH] D22085: Bug 28444: Fix assertion when extract_vector_elt has mismatched type

[Matt Arsenault via llvm-commits]

arsenm created this revision.
arsenm added a subscriber: llvm-commits.

For some reason extract_vector_elt is sometimes allowed to have
a different result type than the vector element type.

http://reviews.llvm.org/D22085

Files:
  lib/CodeGen/SelectionDAG/DAGCombiner.cpp
  test/CodeGen/X86/pr28444.ll

Index: test/CodeGen/X86/pr28444.ll
===================================================================
--- /dev/null
+++ test/CodeGen/X86/pr28444.ll
@@ -0,0 +1,27 @@
+; RUN: llc -mtriple=x86_64-unknown-linux-gnu -mcpu=corei7 < %s | FileCheck %s
+; https://llvm.org/bugs/show_bug.cgi?id=28444
+
+; extract_vector_elt is allowed to have a different result type than
+; the vector scalar type.
+; This uses both
+;  i8 = extract_vector_elt v1i1, Constant:i64<0>
+;  i1 = extract_vector_elt v1i1, Constant:i64<0>
+
+
+; CHECK-LABEL: {{^}}extractelt_mismatch_vector_element_type:
+; CHECK: movb $1, %al
+; CHECK: movb %al
+; CHECK: movb %al
+define void @extractelt_mismatch_vector_element_type(i32 %arg) {
+bb:
+  %tmp = icmp ult i32 %arg, 0
+  %tmp2 = insertelement <1 x i1> undef, i1 true, i32 0
+  %tmp3 = select i1 %tmp, <1 x i1> undef, <1 x i1> %tmp2
+  %tmp6 = extractelement <1 x i1> %tmp3, i32 0
+  br label %bb1
+
+bb1:
+  store volatile <1 x i1> %tmp3, <1 x i1>* undef
+  store volatile i1 %tmp6, i1* undef
+  ret void
+}
Index: lib/CodeGen/SelectionDAG/DAGCombiner.cpp
===================================================================
--- lib/CodeGen/SelectionDAG/DAGCombiner.cpp
+++ lib/CodeGen/SelectionDAG/DAGCombiner.cpp
@@ -12407,7 +12407,7 @@
   // This only really matters if the index is non-constant since other combines
   // on the constant elements already work.
   if (InVec.getOpcode() == ISD::INSERT_VECTOR_ELT &&
-      EltNo == InVec.getOperand(2))
+      EltNo == InVec.getOperand(2) && NVT == VT.getScalarType())
     return InVec.getOperand(1);
 
   // Transform: (EXTRACT_VECTOR_ELT( VECTOR_SHUFFLE )) -> EXTRACT_VECTOR_ELT.


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