[GlobalISel] Don't legalize non-generic instructions.

They don't have types and should be legal.

llvm-svn: 277446

lib/CodeGen/GlobalISel/MachineLegalizePass.cpp

@@ -54,6 +54,12 @@ bool MachineLegalizePass::runOnMachineFunction(MachineFunction &MF) {
       // Get the next Instruction before we try to legalize, because there's a
       // good chance MI will be deleted.
       NextMI = std::next(MI);
+
+      // Only legalize pre-isel generic instructions: others don't have types
+      // and are assumed to be legal.
+      if (!isPreISelGenericOpcode(MI->getOpcode()))
+        continue;
+
       auto Res = Helper.legalizeInstr(*MI, Legalizer);
 
       // Error out if we couldn't legalize this instruction. We may want to fall

test/CodeGen/AArch64/GlobalISel/legalize-ignore-non-generic.mir

@@ -0,0 +1,36 @@
+# RUN: llc -O0 -run-pass=legalize-mir -global-isel %s -o - | FileCheck %s
+# REQUIRES: global-isel
+
+--- |
+  target datalayout = "e-m:o-i64:64-i128:128-n32:64-S128"
+  target triple = "aarch64--"
+  define void @test_copy() { ret void }
+  define void @test_targetspecific() { ret void }
+...
+
+---
+name:            test_copy
+isSSA:           true
+registers:
+  - { id: 0, class: _ }
+body: |
+  bb.0:
+    liveins: %x0
+    ; CHECK-LABEL: name: test_copy
+    ; CHECK: %0(64) = COPY %x0
+    ; CHECK-NEXT: %x0 = COPY %0
+
+    %0(64) = COPY %x0
+    %x0 = COPY %0
+...
+
+---
+name:            test_targetspecific
+isSSA:           true
+body: |
+  bb.0:
+    ; CHECK-LABEL: name: test_targetspecific
+    ; CHECK: RET_ReallyLR
+
+    RET_ReallyLR
+...