Add -verify-arm-pseudo-expand.

This hidden llc option runs the machine code verifier after expanding
ARM pseudo-instructions, but before if-conversion.

The machine code verifier is much better at pointing out liveness errors
that can trip up the register scavenger.

llvm-svn: 136439

llvm/lib/Target/ARM/ARMExpandPseudoInsts.cpp

@@ -26,9 +26,14 @@
 #include "llvm/CodeGen/MachineInstrBuilder.h"
 #include "llvm/Target/TargetFrameLowering.h"
 #include "llvm/Target/TargetRegisterInfo.h"
+#include "llvm/Support/CommandLine.h"
 #include "llvm/Support/raw_ostream.h" // FIXME: for debug only. remove!
 using namespace llvm;
 
+cl::opt<bool>
+VerifyARMPseudo("verify-arm-pseudo-expand", cl::Hidden,
+                cl::desc("Verify machine code after expanding ARM pseudos"));
+
 namespace {
   class ARMExpandPseudo : public MachineFunctionPass {
   public:
@@ -1328,6 +1333,8 @@ bool ARMExpandPseudo::runOnMachineFunction(MachineFunction &MF) {
   for (MachineFunction::iterator MFI = MF.begin(), E = MF.end(); MFI != E;
        ++MFI)
     Modified |= ExpandMBB(*MFI);
+  if (VerifyARMPseudo)
+    MF.verify(this, "After expanding ARM pseudo instructions.");
   return Modified;
 }
 

llvm/test/CodeGen/ARM/crash.ll

@@ -1,4 +1,4 @@
-; RUN: llc < %s -mtriple=thumbv7-apple-darwin10
+; RUN: llc < %s -mtriple=thumbv7-apple-darwin10 -verify-arm-pseudo-expand
 
 ; <rdar://problem/8529919>
 %struct.foo = type { i32, i32 }