implement the new addressing mode description hook.
llvm-svn: 35521
diff --git a/llvm/lib/Target/X86/X86ISelLowering.cpp b/llvm/lib/Target/X86/X86ISelLowering.cpp
index fddb4b2..4c54a28 100644
--- a/llvm/lib/Target/X86/X86ISelLowering.cpp
+++ b/llvm/lib/Target/X86/X86ISelLowering.cpp
@@ -4047,6 +4047,51 @@
}
}
+// isLegalAddressingMode - Return true if the addressing mode represented
+// by AM is legal for this target, for a load/store of the specified type.
+bool X86TargetLowering::isLegalAddressingMode(const AddrMode &AM,
+ const Type *Ty) const {
+ // X86 supports extremely general addressing modes.
+
+ // X86 allows a sign-extended 32-bit immediate field as a displacement.
+ if (AM.BaseOffs <= -(1LL << 32) || AM.BaseOffs >= (1LL << 32)-1)
+ return false;
+
+ if (AM.BaseGV) {
+ // X86-64 only supports addr of globals in small code model.
+ if (Subtarget->is64Bit() &&
+ getTargetMachine().getCodeModel() != CodeModel::Small)
+ return false;
+
+ // We can only fold this if we don't need a load either.
+ if (Subtarget->GVRequiresExtraLoad(AM.BaseGV, getTargetMachine(), false))
+ return false;
+ }
+
+ switch (AM.Scale) {
+ case 0:
+ case 1:
+ case 2:
+ case 4:
+ case 8:
+ // These scales always work.
+ break;
+ case 3:
+ case 5:
+ case 9:
+ // These scales are formed with basereg+scalereg. Only accept if there is
+ // no basereg yet.
+ if (AM.HasBaseReg)
+ return false;
+ break;
+ default: // Other stuff never works.
+ return false;
+ }
+
+ return true;
+}
+
+
/// isLegalAddressImmediate - Return true if the integer value can be used
/// as the offset of the target addressing mode for load / store of the
/// given type.