[X86] Check MI.isConvertibleTo3Addr() before calling convertToThreeAddress in X86Fixu...

X86FixupLEAs just assumes convertToThreeAddress will return nullptr for any instruction that isn't convertible.

But the code in convertToThreeAddress for X86 assumes that any instruction coming in has at least 2 operands and that the second one is a register. But those properties aren't guaranteed of all instructions. We should check the instruction property first.

llvm-svn: 357528

diff --git a/llvm/lib/Target/X86/X86FixupLEAs.cpp b/llvm/lib/Target/X86/X86FixupLEAs.cpp
index 0d8f4a4..9a22731 100644 (file)
--- a/llvm/lib/Target/X86/X86FixupLEAs.cpp
+++ b/llvm/lib/Target/X86/X86FixupLEAs.cpp
@@ -153,6 +153,12 @@ FixupLEAPass::postRAConvertToLEA(MachineFunction::iterator &MFI,
     MFI->insert(MBBI, NewMI); // Insert the new inst
     return NewMI;
   }
+  }
+
+  if (!MI.isConvertibleTo3Addr())
+    return nullptr;
+
+  switch (MI.getOpcode()) {
   case X86::ADD64ri32:
   case X86::ADD64ri8:
   case X86::ADD64ri32_DB: