Fix assertion failure in getMemOperandWithOffsetWidth

This fixes an assertion failure that triggers inside
getMemOperandWithOffset when Machine Sinking calls it on a MachineInstr
that is not a memory operation.

Different backends implement getMemOperandWithOffset differently: some
return false on non-memory MachineInstrs, others assert.

The Machine Sinking pass in at least SinkingPreventsImplicitNullCheck
relies on getMemOperandWithOffset to return false on non-memory
MachineInstrs, instead of asserting.

This patch updates the documentation on getMemOperandWithOffset that it
should return false on any MachineInstr it cannot handle, instead of
asserting. It also adapts the in-tree backends accordingly where
necessary.

Differential Revision: https://reviews.llvm.org/D71359

1 files changed, 4 insertions, 2 deletions

diff --git a/llvm/lib/Target/Lanai/LanaiInstrInfo.cpp b/llvm/lib/Target/Lanai/LanaiInstrInfo.cpp
index 306cdc77d0d..4ce72f9621a 100644
--- a/llvm/lib/Target/Lanai/LanaiInstrInfo.cpp
+++ b/llvm/lib/Target/Lanai/LanaiInstrInfo.cpp
@@ -788,8 +788,10 @@ bool LanaiInstrInfo::getMemOperandWithOffsetWidth(
 
   BaseOp = &LdSt.getOperand(1);
   Offset = LdSt.getOperand(2).getImm();
-  assert(BaseOp->isReg() && "getMemOperandWithOffset only supports base "
-                            "operands of type register.");
+
+  if (!BaseOp->isReg())
+    return false;
+
   return true;
 }