[CGP] Fix Complex addressing mode for offset

If the offset is differ in two addressing mode we can continue only if
ScaleReg is not set due to we will use it as merge of different offsets.

It should fix PR35799 and PR35805.

Reviewers: john.brawn, reames
Reviewed By: reames
Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D41227

llvm-svn: 322056

1 files changed, 6 insertions, 1 deletions

diff --git a/llvm/lib/CodeGen/CodeGenPrepare.cpp b/llvm/lib/CodeGen/CodeGenPrepare.cpp
index 9dc1ab4e6bb..26ca8d4ee88 100644
--- a/llvm/lib/CodeGen/CodeGenPrepare.cpp
+++ b/llvm/lib/CodeGen/CodeGenPrepare.cpp
@@ -2700,8 +2700,13 @@ public:
     // we still need to collect it due to original value is different.
     // And later we will need all original values as anchors during
     // finding the common Phi node.
+    // We also must reject the case when base offset is different and
+    // scale reg is not null, we cannot handle this case due to merge of
+    // different offsets will be used as ScaleReg.
     if (DifferentField != ExtAddrMode::MultipleFields &&
-        DifferentField != ExtAddrMode::ScaleField) {
+        DifferentField != ExtAddrMode::ScaleField &&
+        (DifferentField != ExtAddrMode::BaseOffsField ||
+         !NewAddrMode.ScaledReg)) {
       AddrModes.emplace_back(NewAddrMode);
       return true;
     }