[llvm] r250885 - Let MachineVerifier be aware of mem-to-mem instructions.

[Jonas Paulsson via llvm-commits]

Author: jonpa
Date: Wed Oct 21 02:39:47 2015
New Revision: 250885

URL: http://llvm.org/viewvc/llvm-project?rev=250885&view=rev
Log:
Let MachineVerifier be aware of mem-to-mem instructions.

A mem-to-mem instruction (that both loads and stores), which store to an
FI, cannot pass the verifier since it thinks it is loading from the FI.

For the mem-to-mem instruction, do a looser check in visitMachineOperand()
and only check liveness at the reg-slot while analyzing a frame index operand.

Needed to make CodeGen/SystemZ/xor-01.ll pass with -verify-machineinstrs,
which now runs with this flag.

Reviewed by Evan Cheng and Quentin Colombet.

Modified:
    llvm/trunk/lib/CodeGen/MachineVerifier.cpp
    llvm/trunk/test/CodeGen/SystemZ/xor-01.ll

Modified: llvm/trunk/lib/CodeGen/MachineVerifier.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/MachineVerifier.cpp?rev=250885&r1=250884&r2=250885&view=diff
==============================================================================
--- llvm/trunk/lib/CodeGen/MachineVerifier.cpp (original)
+++ llvm/trunk/lib/CodeGen/MachineVerifier.cpp Wed Oct 21 02:39:47 2015
@@ -994,11 +994,17 @@ MachineVerifier::visitMachineOperand(con
         LiveInts && !LiveInts->isNotInMIMap(MI)) {
       LiveInterval &LI = LiveStks->getInterval(MO->getIndex());
       SlotIndex Idx = LiveInts->getInstructionIndex(MI);
-      if (MI->mayLoad() && !LI.liveAt(Idx.getRegSlot(true))) {
+
+      // For a memory-to-memory move, we don't know if MI is using
+      // this frame index for loading or storing, so check for
+      // liveness at reg-slot only in the simple load case.
+      bool stores = MI->mayStore();
+      bool simpleLoad = (MI->mayLoad() && !stores);
+      if (simpleLoad && !LI.liveAt(Idx.getRegSlot(true))) {
         report("Instruction loads from dead spill slot", MO, MONum);
         errs() << "Live stack: " << LI << '\n';
       }
-      if (MI->mayStore() && !LI.liveAt(Idx.getRegSlot())) {
+      if (stores && !LI.liveAt(Idx.getRegSlot())) {
         report("Instruction stores to dead spill slot", MO, MONum);
         errs() << "Live stack: " << LI << '\n';
       }

Modified: llvm/trunk/test/CodeGen/SystemZ/xor-01.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/CodeGen/SystemZ/xor-01.ll?rev=250885&r1=250884&r2=250885&view=diff
==============================================================================
--- llvm/trunk/test/CodeGen/SystemZ/xor-01.ll (original)
+++ llvm/trunk/test/CodeGen/SystemZ/xor-01.ll Wed Oct 21 02:39:47 2015
@@ -1,6 +1,6 @@
 ; Test 32-bit XORs in which the second operand is variable.
 ;
-; RUN: llc < %s -mtriple=s390x-linux-gnu -mcpu=z10 | FileCheck %s
+; RUN: llc < %s -verify-machineinstrs -mtriple=s390x-linux-gnu -mcpu=z10 | FileCheck %s
 ; RUN: llc < %s -mtriple=s390x-linux-gnu -mcpu=z196 | FileCheck %s
 
 declare i32 @foo()