The DAGCombiner was threading select over pairs of extending loads even
if the extension types were not the same. The result was that if you
fed a select with sext and zext loads, as in the testcase, then it
would get turned into a zext (or sext) of the select, which is wrong
in the cases when it should have been an sext (resp. zext). Reported
and diagnosed by Sebastien Deldon.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@119728 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/SelectionDAG/DAGCombiner.cpp b/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
index 1a0f503..53b4493 100644
--- a/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
+++ b/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
@@ -6658,6 +6658,11 @@
LLD->isVolatile() || RLD->isVolatile() ||
// If this is an EXTLOAD, the VT's must match.
LLD->getMemoryVT() != RLD->getMemoryVT() ||
+ // If this is an EXTLOAD, the kind of extension must match.
+ (LLD->getExtensionType() != RLD->getExtensionType() &&
+ // The only exception is if one of the extensions is anyext.
+ LLD->getExtensionType() != ISD::EXTLOAD &&
+ RLD->getExtensionType() != ISD::EXTLOAD) ||
// FIXME: this discards src value information. This is
// over-conservative. It would be beneficial to be able to remember
// both potential memory locations. Since we are discarding